Advancements in Cosmetic Science: A Review of Ingredients and Technologies for Holistic Health and Longevity

Abstract

Recent advancements in cosmetic science and personal care represent a fundamental shift from conventional esthetics toward integrative solutions that support both physical health and emotional well-being. This review highlights the latest innovations in ingredients and technologies across skincare, hair care, and dental care, emphasizing their role in enhancing physiological resilience, modulating immune responses, and promoting emotional balance. A key focus is the development of multifunctional personal care products that bridge the gap between external esthetics and internal physiological benefits, reflecting the growing intersection of cosmetic and health sciences. Additionally, this review examines the therapeutic potential of aromatherapy and phytoncides in enhancing mood, reinforcing the critical role of mental well-being in overall health. As the personal care industry continues to evolve, the convergence of chemistry and medical disciplines relevant to cosmetic science—including those focused on skin, hair, oral health, sensory perception, mental well-being, and longevity—is driving a new era of holistic, evidence-based self-care that enhances both esthetic appearance and overall health.

1. Introduction

The interplay between physical health, emotional well-being, and longevity has become an area of increasing scientific interest, shifting the understanding of aging from a purely chronological process to a multifaceted interaction of biological, psychological, and environmental factors [1,2,3]. This evolving perspective has not only advanced research but has also attracted public and media interest, driving demand for holistic approaches that integrate mind–body interventions into skincare, hair care, and oral care, considering both esthetic and functional benefits [4,5]. Growing recognition of mental health’s influence on aging has further reinforced the demand for interventions that support both physiological resilience and emotional well-being [6,7,8]. This shift has encouraged significant innovations in cosmetic science, leading to the development of bioactive ingredients and advanced technologies that move beyond superficial effects to promote systemic well-being and longevity [9,10].

Among these advancements, the emerging field of neurocosmetics, particularly aromatherapy-based formulations, illustrates how cosmetic science is increasingly leveraging olfactory and neuroendocrine pathways to potentially affecting mood, stress, and emotional well-being while mitigating physical signs of biological aging [6,7,8,10]. Furthermore, advances in biomimetic materials, adaptogens, antioxidants, and microbiome-supportive ingredients reflect a growing understanding of the roles of cellular resilience, immune function, and neural signaling in the aging process.

The intersection of dermatology, dentistry, neuroscience, and longevity research is contributing to recent developments in personal care research. Cosmetic innovations not only enhance skin, hair, and oral health but also serve as integrative tools for potentially influencing health span and lifespan, highlighting the relevance of a truly interdisciplinary approach in cosmetic science.

This review provides a comprehensive evaluation of scientifically validated strategies that integrate physical and mental health considerations into modern personal care. By examining bioactive ingredients and emerging methodologies across skincare, hair care, and dental care, it describes their effects on physiological function and esthetic outcomes (

Table 1. Summary table of reported ingredients and their scientific properties.

		Properties	Description	References	Strength of Evidence
SKIN CARE	Peptides-Based Ingredients
	Acetyl tetrapeptide-5	Reduced “puffy eyebags” and “dark circles.”	Acetyl tetrapeptide-5 exhibits a draining and decongestant effect that results in improved hydration and elasticity in the periocular area, contributing to a reduction in eye edema and dark circles.	[11,12]	Low
	Copper tripeptide	Enhances skin regeneration. Improves skin density. Reduces slack skin. Diminishes fine lines and wrinkles.	GHK-Cu benefits both skin fibroblasts and epidermal basal cells by enhancing cell viability, growth factor production, and stemness markers, thereby aiding in skin repair.	[13,14,15,16,17,18]	Low
	Dipeptide diaminobutyroyl benzylamide diacetate	Diminishes wrinkles.	Tripeptide-3 acts as an intensive anti-wrinkle agent by mimicking Waglerin-1’s mechanism of action on nAChRs, effectively reducing muscle contractions and promoting facial muscle relaxation.	[19,20,21]	Low
	Naturally Derived Ingredients
	Ectoin	Enhances skin hydration, elasticity, and surface structure. Has antinflammatory properties.	Ectoin protects cell membranes by forming a water shell (ectoin hydrocomplex) around proteins, finally enhancing skin hydration and reducing transepidermal water loss (TEWL).	[22,23,24,25,26]	Strong
	Aloe vera leaf extract and Trimethylglycine	Promotes immediate and long-term skin hydration. Normalizes sebaceous gland activity. Maintains skin pH balance.	The combination of Aloe vera (Aloe barbadensis) leaf extract and trimethylglycine in equal mass ratio has shown significant efficacy in increasing AQP3 levels within epidermal cells.	[27,28,29]	Strong
	Prunus mume fruit extract	It has skin-whitening, anti-aging and antioxidant effects.	Research indicates that P. mume extracts can inhibit melanin production and tyrosinase activity without causing cytotoxicity.	[30,31]	Strong
	Andrographolide	It has anti-aging and antioxidant effects. Reduces bilirubin levels, a major cause of dark circles around the eyes.	Clinical results revealed that formulations containing APE significantly improve skin hydration, dermal density, wrinkles, and sagging after four and eight weeks of treatment.	[32,33,34]	Low
HAIR CARE	Peptides-Based Ingredients
	Copper tripeptide	Enhances hair growth and thickness. Enlarges hair follicle size. Improves hair transplant success rates.	The tripeptide–copper complex exerts its effects through several mechanisms, including the stimulation of dermal fibroblasts and increased expression of VEGF. Additionally, GHK-Cu has been shown to decrease the secretion of transforming growth factor-β1 by dermal fibroblasts and reduce the number of apoptotic dermal papilla cells.	[35,36]	Low
	Naturally Derived Ingredients
	Biotin	Plays a significant role in keratin production.	Aside from conditions like alopecia and uncombable hair syndrome, there is no scientific validation of biotin’s efficacy in enhancing hair quality or quantity in individuals without a deficiency.	[37,38]	Low
	Wasabi	Promotes hair growth.	Recent research by Yamada-Kato Et Al. (2018) has highlighted the potential of 6-MSITC (derived from Wasabi) in promoting hair growth through its effects on dermal papilla cells (DPCs), which play a key role in hair growth and cycling by releasing growth factors.	[39]	Low
	Vanyline	Helps prevent hair loss.	Vanillyl butyl ether can help to prevent hair loss by increasing insulin-like growth factor (IGF-2) production, crucial for hair stem cell proliferation.	[40,41,42]	Low
	Shikimic acid	Promotes hair growth.	SA exhibits reprogramming activities in human dermal fibroblasts, is effective for tissue regeneration, and has shown promising results in promoting hair growth in both in vivo mouse models and in vitro human hair follicles (HFs).	[43,44,45]	Low
	Tetrahydroxystilbene Glucoside	Enhances melanin synthesis. Reduces hair loss. Increases hair thickness.	Extracted from the root of Polygonum multiflorum, tetrahydroxystilbene glucoside enhances melanin synthesis in human SKMEL-28 melanoma cells through the activation of the MC1R/MITF/tyrosinase signaling pathway.	[46,47]	Strong
ORAL CARE	Naturally Derived Ingredients
	Hydroxyapatite	Promotes tooth remineralization. Prevents caries. Reduces dentin hypersensitivity. Reduces biofilm formation.	HAP toothpastes can penetrate deeper into lesions, leading to results that are equivalent or non-inferior to fluoride toothpastes in terms of remineralizing initial caries lesions and preventing carious lesion development.		Strong
	Aspartic Acid	Plays a critical role in the biomimetic remineralization of demineralized dentin.	This approach results in remineralized dentin that exhibits mechanical and biological properties potentially similar to natural teeth, achieved through both internal and external mineralization of collagen fibers. When combined with 1% hydroxyapatite, remineralization was markedly enhanced.	[48,49,50,51,52,53,54]	Low
	DL–Malic Acid	Tooth-whitening agent. Reduce the surface hardness of the tooth over time.	Malic acid acts as a tooth-whitening agent by oxidizing the surface of tooth enamel. This oxidation process involves the release of free oxygen radicals that target the double bonds of both organic and inorganic compounds in teeth, thereby facilitating the dissolution of stains.	[55,56]	Low
MENTAL WELL-BEING	Aromatherapy	Accumulating evidence from neuroimaging studies reveals that olfactory stimulation can modulate neural activity in regions associated with mood and emotion, suggesting a tightly interwoven relationship between olfactory pathways and emotional regulation. This interaction results in immediate physiological responses, such as alterations in blood pressure, muscle tension, pupil dilation, skin temperature, heart rate, and brain activity.		[57,58,59]	Low
	Phytoncides
	Japanese cedar	Favors stress release.	Japanese cedar wood essential oil increased salivary dehydroepiandrosterone sulfate (DHEA-s) levels in males after cognitive tasks, suggesting stress-relief effects during rest periods	[60]	Low
	D-limonene	Promotes relaxation.	olfactory stimulation with D-limonene significantly increased parasympathetic nervous activity, decreased heart rate, and enhanced feelings of comfort, highlighting the compound’s role in promoting relaxation.	[61]	Low
	Abies sibirica	Reduces arousal levels.	Breathing air mixed with volatiles from the essential oil of Abies sibirica induced reduced arousal levels after visual display terminal (VDT) tasks, as measured by changes in heart rates and brain waves, underling a potential benefit in preventing VDT-related mental health disturbances such as sleep disorders, restlessness, and anxiety.	[62]	Low

). Additionally, it explores holistic interventions that promote mental well-being, reinforcing the importance of an evidence-based, longevity-driven approach to personal care and healthy aging.

2. Skin Care

Human skin, located at the interface between the organism and its environment, is continually exposed to a range of environmental factors such as ultraviolet (UV) radiation, environmental pollutants, wind, humidity, and temperature extremes [22]. Along with the natural process of chronological aging, these factors contribute to accelerated skin aging [11,12]. This complex biological process is typically characterized by the appearance of wrinkles, slack skin, dryness, rough skin texture, and thinning of the epidermis due to intrinsic aging [12]. In contrast, photoaging—a major extrinsic factor—manifests with a thickened epidermis, deep furrows, redness from burns, uneven pigmentation, severe skin atrophy, and diminished collagen fibers [22]. The impact of skin aging may extends beyond physical health, potentially affecting social interactions and self-esteem [30]. A youthful appearance has been often associated with increased self-confidence and a favorable social impression, underscoring the societal relevance of managing skin aging. The global increase in the aging population has therefore driven a demand for effective anti-aging strategies, leading to extensive research in this field [63]. The production of various skincare products is continually evolving and faces numerous challenges. Among these, transdermal delivery of compounds represents a significant limitation due to the skin’s barrier properties, especially for molecules with high molecular weight, hydrophilicity, polarity, or vulnerability to enzymatic degradation [64,65]. To enhance permeation, various delivery systems such as nanoemulsions, solid lipid nanoparticles, and nanocapsules are employed [13]. Liposomes, in particular, are extensively used in cosmetic applications and transdermal delivery, aiming to increase the concentration of active agents within the skin. Despite the biodegradable and non-toxic nature of phospholipids, liposomes suffer from low physical and chemical stability and limited skin permeation when used topically [65]. A promising strategy to improve their efficacy involves surface modification with cell-penetrating peptides (CPPs), which has been demonstrated to significantly enhance compound permeation [64,66].

Amidst challenges and innovations, scientific research advances every day, identifying various candidate molecules for developing new anti-aging products, further driving innovation in this area.

2.1. Peptides-Based Ingredients

2.1.1. Acetyl Tetrapeptide-5

The infraorbital skin is exceptionally thin, measuring just 0.5 mm thick, about four times thinner than the skin in most other regions of the body [67]. This reduced thickness accentuates age-related changes, making periorbital concerns such as edema (‘puffy eye bags’) and hyperpigmentation (‘dark circles’) more apparent in this delicate area.

Acetyl tetrapeptide-5 is a synthetic tetrapeptide that targets periocular skin changes through several complementary mechanisms [67]. It enhances the vascular system by reducing vascular permeability and strengthens the skin under the eyes by protecting the collagen structural network against glycan-induced degradation, thereby preventing fluid accumulation in the skin’s interstitial compartment [67]. In vitro studies demonstrated that acetyl tetrapeptide at a concentration of 1 mg/mL reduced vascular permeability by 50%. Subsequent in vivo evaluation involving 20 volunteers aged 18 to 65, using a 0.01% acetyl tetrapeptide formulation, showed noticeable improvement in 35% of participants after 15 days of application [68]. Additionally, acetyl tetrapeptide-5 showed a draining and decongestant effect that results in improved hydration and elasticity in the periocular area, contributing to a reduction in eye edema and dark circles, through its inhibition of the angiotensin-converting enzyme (ACE) [11,12]. Although the results are promising, they are based on a single study involving 20 patients aged between 18 and 65 years. Further clinical studies with larger and more stratified cohorts are needed to strengthen the evidence and to better characterize the effects of the cream across different patient subgroups.

2.1.2. Copper Tripeptide (GHK-Cu)

One of the most widely used peptides in skin and hair products is copper-binding tripeptide (GHK-Cu). It has been recognized for its profound wound-healing and skin regenerative properties through various cell, tissue, and animal studies [13,14,15,16].

GHK-Cu has been shown to enhance skin regeneration by stimulating collagen and glycosaminoglycan synthesis, modulating metalloproteinases, promoting balanced skin protein breakdown, and supporting dermal fibroblast function [13,14,17]. GHK-Cu benefits both skin fibroblasts and epidermal basal cells by enhancing cell viability, growth factor production, and stemness markers, thereby supporting skin repair [17]. In vitro studies have shown that GHK’s treatment significantly increases normal human keratinocyte proliferation in monolayer cultures. It improves the microenvironment of epidermal basal cells by increasing the number of p63-positive cells, a marker for skin stem cells, and by modulating the levels of integrin α6 and integrin β1, enhancing cellular stemness and proliferative potential [17].

Topical applications of GHK-Cu in various formulations have been clinically proven to significantly improve skin appearance. GHK-Cu facial cream treatments have shown improvements in skin density, reduced slack skin, enhanced clarity, and diminished fine lines and wrinkles in a clinical controlled but non-randomized trial involving 71 women with signs of photoaging [15]. Additionally, a study involving 20 healthy subjects has demonstrated that applying GHK-Cu to thigh skin for one month increased dermal procollagen synthesis in 70% of treated women, surpassing the results achieved by vitamin C (50%) and retinoic acid (40%) treatments [18].

Finally, both GHK and GHK-Cu exhibit potent antioxidant and anti-inflammatory properties. GHK-Cu, in particular, demonstrates enhanced antioxidant effects and suppresses inflammatory responses by modulating NF-κB, p65, and p38 MAPK signaling pathways [14,16]. Recent gene profiling studies confirmed that GHK, both with and without copper, influences expression level of numerous genes related to an organism’s response to stress and injury, encompassing tissue remodeling, antioxidant, anti-inflammatory, analgesic, anxiolytic, angiogenic, neurogenic, and anticancer actions [15].

GHK and its Cu-chelate possess the ability to stimulate skin remodeling, enhance wound healing and tissue regeneration, and exert strong antioxidant and anti-inflammatory effects, which collectively support their potential utility in promoting healthy aging. While further research is necessary, the available experimental and clinical data provide an initial rationale for further preclinical and clinical investigation of this endogenous peptide. Given its potential long-term effects on attenuating age-related changes, GHK may substantially improve quality of life in aging populations. Moreover, its use in combination with other anti-aging agents may represent a valuable multi-targeted strategy to more effectively support healthy aging [16].

2.1.3. Dipeptide Diaminobutyroyl Benzylamide Diacetate

Snake venoms are intricate mixtures known for their potent biochemical diversity, encompassing peptides as significant components [19]. Among these, Waglerins, originating from the venom of the Temple Viper, Tropidolaemus wagleri, have garnered attention due to their neurotoxic properties mediated by interaction with muscle nicotinic acetylcholine receptors (nAChRs) [19,20]. Interestingly, Waglerin-1 has inspired the development of the therapeutic dipeptide diaminobutyroyl benzylamide diacetate (tripeptide-3), renowned for its anti-aging effects. Tripeptide-3 acts as an intensive anti-wrinkle agent by mimicking Waglerin-1’s mechanism of action on nAChRs, effectively reducing muscle contractions and promoting facial muscle relaxation [20]. This action is central in diminishing expression wrinkles, thereby counteracting visible signs of aging on facial skin.

Tripeptide-3, at a concentration of 0.5 mmol L⁻¹, significantly reduced the frequency of innervated muscle cell contractions by 82% (p < 0.05) after just 2 h of treatment [20]. Research involving 45 healthy subjects showed significant before-and-after tripeptide-3 treatment improvements, with the most notable results observed on forehead skin, where innervation frequency was reduced by up to 52% [20]. Additionally, a randomized study including 57 volunteers (50–65 years) investigated the effects of a 4% diaminobutyroyl benzylamide diacetate formulation applied for four weeks. Facial images were analyzed using image processing, expert grading and Primos^lite measurements. Compared with placebo, the active formulation resulted in a significant reduction in glabellar and crow’s feet wrinkle parameters; reductions in hyperpigmentation and perceived age were also observed, whereas no improvement was detected in marionette lines. The authors suggested that this regional difference might be related to local skin thickness [21].

2.2. Naturally Derived Ingredients

2.2.1. Ectoin

Ectoin (1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid) is a neutral, non-ionic organic molecule with a strong water-binding capacity and low molecular weight, derived from halophilic bacteria that grow in extreme environments such as salt lakes, seawater, and saline deserts [23]. In nature, these bacteria synthesize ectoin to protect themselves from intense sunlight, high temperatures, and extreme dryness, due to its ability to shield biopolymers from external stressors like UV radiation [23]. While ectoin does not directly absorb UV rays, it effectively prevents damage to Langerhans cells and reduces the formation of sunburn cells through other still non-clarified mechanisms [23]. Ectoin protects cell membranes by forming a water shell (ectoin hydrocomplex) around proteins, finally enhancing skin hydration and reducing transepidermal water loss (TEWL) [24,25]. Topical application of ectoine (7%) for 6 months led to improved hydration of the outer layer of the epidermis, the stratum corneum, and TEWL [69].

Ectoin further protects cells from stress conditions and prevents cell damage by upregulating heat shock proteins, notably hsp70, crucial for shielding skin tissue from heat, cytotoxic drugs, toxins, UV radiation, and other environmental stressors such as pollutants [26].

Ectoin’s protective and chemical characteristics make it versatile for use in various cosmetic formulations. A monocentric, randomized, double-blind, vehicle-controlled clinical study assessed the effects of a skincare formulation containing 2% ectoin in a total of 104 healthy subjects (30–60 years) with normal, dry, and sensitive skin. The test product was applied twice daily for 4 weeks, and no adverse effects were reported by any of the participants. After one month of treatment, the 2% ectoin formulation significantly improved skin hydration, elasticity, and surface structure and was preferred by study participants over the vehicle for its anti-aging effects. These findings are noteworthy, as the reference product was not a placebo but a high-quality skincare formulation used as the vehicle in this study [22]. Additionally, ectoin’s hydrating and inflammation-reducing properties have been used to address compromised epidermal barrier functions, crucial for managing skin conditions like atopic dermatitis and psoriasis. A systematic literature review including six studies (five studies on atopic dermatitis and one study on prevention and management of retinoid dermatitis) showed that the application of topical formulations containing 5.5–7.0% ectoine positively influenced skin dryness and, consequently, pruritus and dermatitis-specific scores in patients with atopic dermatitis. Especially in infants and children, who belong to the most frequently affected group, the formulations were well-tolerated when applied for up to 4 weeks. No differences were found between 5.5% and 7% ectoine-containing formulations and creams or emollients; however, no directly comparative data were identified between ectoine concentration and formulation [24]. Overall, current data are promising and suggest that topical ectoine can improve both clinical symptoms and subjective discomfort in various inflammatory skin conditions. Nevertheless, these results should be interpreted with caution due to the limited number of available studies and the small sample sizes, particularly in retinoid-induced dermatitis. The heterogeneity of study populations, treatment regimens, and application periods further limits the comparability of the findings [24].

2.2.2. Aloe Vera Leaf Extract and Trimethylglycine

Reduced aquaporin type 3 (AQP3) expression is associated with skin aging and various dermatological conditions such as atopic dermatitis, psoriasis, chronic skin irritation, and vitiligo [27]. AQP3 plays a crucial role in transporting water, glycerol, and natural moisturizing factors, thereby enhancing skin hydration, keratinocyte proliferation, and wound healing [28]. The combination of Aloe vera (Aloe barbadensis) leaf extract and trimethylglycine in a 1:1 mass ratio showed a clear synergistic effect, increasing AQP3 levels up to twofold in an in vitro model of skin keratinocytes. This result confirms that the combination of Aloe barbadensis extract, standardized for aloin, and trimethylglycine has promising potential for drug development and the treatment of dry skin [27].

Aloe vera is known for its antimicrobial, soothing, and anti-inflammatory properties, attributed to its bioactive compounds like bradykinase, aloin, phytosterols, and vitamins C and E. These components not only protect the skin from UV radiation and environmental pollutants but also promote collagen synthesis and improve skin elasticity [29]. Trimethylglycine, derived from sugar beet roots (Beta vulgaris), enhances the softness and elasticity of the epidermal corneal layer by effectively binding water. It also protects proteins and DNA from damage, supporting prolonged cellular function and healthier skin appearance [29]. As an osmolyte, trimethylglycine supports optimal metabolic activity in keratinocytes, particularly beneficial in dry skin conditions, thereby restoring hydration and maintaining skin health. Though the combination of Aloe barbadensis leaf extract and trimethylglycine is not novel, its newly discovered effect has now been thoroughly investigated by means of in silico, in vitro, and clinical research [29]. In silico modeling of the interaction of the biologically active compounds with AQP3 was performed using Phyto4Healthmodeling. The analysis revealed that the two molecules exhibit moisturizing effects, anti-inflammatory properties, and efficacy against eczema. In vitro experiments demonstrated enhanced keratinocyte viability and a significant elevation in AQP3 levels in epidermal cells when exposed to novel combination of Aloe barbadensis leaf extract and trimethylglycine, in a 1:1 mass ratio corresponding to raw active ingredient concentrations of 0.01 and 1.00 wt.%, respectively. This AQP3 stimulation effect was significantly greater, by 1.77 fold, than the effect of the commercially named Hydagen^® Aquaporin (BASFSE, Pulnoy, France), known for its ability to influence the amount of AQP3 in skin epidermal cells [29]. Finally, a prospective, open-label, non-randomized, controlled clinical study was conducted to assess the efficacy of the formulations under real-use conditions. A total of 60 subjects, aged 18 to 62 years, were instructed to apply a shower gel and a 2-in-1 shower gel containing the novel moisturizing combination of Aloe barbadensis leaf extract and trimethylglycine twice daily (morning and evening) for 28 days. Dermatological evaluation revealed an immediate increase in skin hydration 5 min after use. A strong moisturizing effect was observed in 93% of the healthy volunteers and, compared to baseline, epidermal hydration increased by 236% 5 min after a single application of the shower gel. Furthermore, subjects’ self-assessments indicated a high level of satisfaction with the formulation characteristics and the resulting skin appearance, without any relevant adverse events being reported [29].

This combination appears highly promising for further research and for the development of cosmetic and pharmaceutical products aimed at the prevention and treatment of skin xerosis, dermatitis, atopic dermatitis, psoriasis, eczema, and other dryness-related conditions. In addition, this innovation is also the subject of an international patent application (WO 2024/141322), which details the use of a plant-mineral composition based on Aloe barbadensis leaf extract and trimethylglycine (betaine) for regulation of type 3 aquaporins and transepidermal water flow in deep epidermal layers [27].

2.2.3. Prunus Mume Fruit Extract

Prunus mume, commonly known as Maesil, has been traditionally used in East Asian countries as both a medicinal and culinary ingredient, renowned for its antioxidant and anti-obesity properties [31]. Recently, P. mume has gained attention in skin care for its potential skin-whitening and anti-aging effects [31]. Skin color is primarily determined by melanin content, which is synthesized by melanocytes under the control of the enzyme tyrosinase. While melanin protects the skin against UV light, its abnormal accumulation can lead to hyperpigmentation disorders such as freckles and age spots [31]. Research indicates that P. mume extracts can inhibit melanin production and tyrosinase activity without causing cytotoxicity. Studies using α-MSH-stimulated B16/F10 murine melanoma cells suggest that P. mume extract achieves this by decreasing tyrosinase expression at the transcriptional level through the inhibition of MITF expression, obtained via ERK activation and reduced CREB phosphorylation [31].

Son et al. demonstrated that P. mume fruit extracts, particularly the ripe seed extract (PmRS), also exhibit strong antioxidant effects [30]. PmRS was shown to reduce UVB-induced ROS levels, suppress MMP-1 and MMP-13 elevations, and increase TIMP-1 and SIRT1 expressions. In vivo experiments on mice further validated PmRS’s skin-protective effects, enhancing collagen levels by 38% and reducing skin thickness by 27% compared to the UV-irradiated group [30]. The seed extract of P. mume was prepared from unripe fruit, ripe fruit, and seed fractions using 50% ethanol. The extract of mature PmRS exhibited the most potent antioxidant effects compared with extracts from unripe or ripe fruit, with no cytotoxicity up to 100 μg/mL [30]. It was estimated in 2010 that 500 tons of P. mume seeds are wasted annually as a by-product in Japan [30]. Since the seed, including the stone, accounts for up to 40% of the whole fruit, it represents a plentiful and underexploited resource. These findings highlight the potential of P. mume seeds for incorporation into food and nutraceutical products, offering a way to valorize this biomass while providing functional benefits.

2.2.4. Andrographolide

Andrographolide, a major labdane diterpenoid isolated from the leaves of Andrographis paniculata (commonly known as “Green Chiretta” or “King of bitters”), is renowned in Ayurvedic medicine for its detoxifying properties [70,71]. This compound exhibits a range of beneficial effects, including antiviral, anti-inflammatory, and antioxidative properties, and is known to modulate cannabinoid receptors [72,73,74,75].

Recent investigations into the effects of Andrographis paniculata extract (APE) on human epidermal stem cells (EpSCs) have demonstrated significant anti-aging properties through a series of in vitro, ex vivo, and in vivo studies [32]. APE has been shown to markedly promote the proliferation of EpSCs, notably increasing the G2/M and S stages of the cell cycle in a dose-dependent manner. This proliferation is associated with the upregulation of integrin β1 expression, a key marker of epidermal progenitor cell expansion, both in vitro and in skin explants [32]. Furthermore, APE treatment significantly enhances VEGF production in EpSCs, which, in turn, stimulates type 1 collagen synthesis in normal human fibroblasts (NHFs), suggesting a paracrine mechanism [32]. Clinical results from a group of 32 female subjects (40–50 years), revealed that formulations containing APE significantly improve skin hydration (6.49% vs. 7.77%, control and APE group, respectively) after eight weeks of treatment. Dermal density, wrinkles, and sagging resulted also significantly improved after four and eight weeks of treatment [32]. Bayazid et al. have highlighted APE’s ability to mitigate UVB-induced damage in HaCaT cells by enhancing protective elements such as HAS-1, AQP3, loricrin, and PPAR-α, while inhibiting MAPK hyperphosphorylation and pro-inflammatory cytokine expression. In addition, the study results revealed that ALE exhibited a high concentration of polyphenols and flavonoids, which were associated with potent abiotic antioxidant properties [33]. Finally, recent studies have demonstrated that andrographolide also exhibits a hepatoprotective effect by stimulating detoxification and reducing bilirubin levels, a major cause of dark circles around the eyes, thus potentially diminishing this common sign of skin fatigue [34]. The available evidence strongly suggests that ALE has potential for supporting and strengthening the skin barrier, a key defense against various skin disorders and a fundamental factor in overall skin health. While these findings indicate a possible application of ALE in skin-care formulations, additional clinical data are required to confirm these effects.

3. Hair Care

Alongside skincare, the field of haircare is gaining increasing importance in contemporary society. Various hair disorders significantly impact individuals’ daily lives. Among them, alopecia, commonly referred to as hair loss, is frequently encountered in dermatology clinics and can be classified into cicatricial (scarring) and non-cicatricial (non-scarring) types, with the former leading to irreversible hair loss and the latter being potentially reversible [76]. Various factors such as genetics, hormones, autoimmune conditions, and nutrition contribute to hair loss [76]. The visible impact of alopecia on appearance significantly affects individuals’ psychological and social well-being, causing distress, reduced self-esteem, and social withdrawal [39]. In addressing these challenges, research has focused on hair care solutions involving functional food extracts, peptides, plant extracts, and dietary supplements rich in essential vitamins and minerals. Because micronutrients are major elements of the hair follicle cycle, they are indeed among the preferred methods for preventing alopecia [76]. These approaches aim to stimulate hair growth and prevent further loss, offering a holistic strategy to enhance both the physical and emotional well-being of affected individuals.

In addition, hair color, a prominent aspect of human appearance, often signifies aging, ill health, and bodily decline. It is influenced by a complex interplay of elements, including aging, achromotrichia, stress, medical conditions, and artificial factors, with its regulation involving a network of cytokines and proteins [46]. Driven by the desire to preserve youth and vitality, significant research into premature graying has led the pharmaceutical and functional food industries to seek effective prevention and treatment strategies [46,77].

3.1. Peptides-Based Ingredients

Copper Tripeptide, GHK-Cu

As previously discussed, GHK-Cu has been widely recognized for its multifaceted role in tissue remodeling and repair processes. In the realm of hair care, GHK-Cu has demonstrated the ability to enhance hair growth and thickness, enlarge hair follicle size, and improve hair transplant success rates [35,36]. The tripeptide–copper complex exerts its effects through several mechanisms, including the stimulation of dermal fibroblasts and increased expression of VEGF [36]. Additionally, GHK-Cu has been shown in a model of dermal papillary cells in vitro to decrease the secretion of transforming growth factor-β1 by dermal fibroblasts and reduce the number of apoptotic dermal papilla cells, evidenced by an elevated Bcl-2/Bax ratio and reduced levels of cleaved forms of caspase-35 [78]. Beyond hair growth, GHK-Cu has demonstrated significant repair actions across various tissues, including hair follicles. In vivo studies have observed that mice treated with intradermal injections of GHK-Cu-treated showed exceptionally large hair follicles at the periphery of the wound, indicating stimulation of follicular cell proliferation, resulting in the enlargement of anagen follicles from vellus to terminal types and underscoring its potential role in hair growth therapeutic approaches [35].

Building on these properties, analogs of GHK-Cu containing additional hydrophobic amino acid residues are commercially employed in hair transplantation procedures (e.g., Graftcyte^®). In two clinical trials, these modified peptides were shown to significantly decrease post-transplant skin crusting, shortening the duration from approximately 10–14 days to only 5 days. Furthermore, the rate of hair graft shedding was reduced from about 30% (in the saline-treated control group) to roughly 10%. The onset of new hair growth was accelerated by approximately 50%, and overall patient satisfaction increased from 80% to 95% following treatment [35].

3.2. Naturally Derived Ingredients

3.2.1. Biotin

Biotin, a water-soluble B vitamin, is a crucial cofactor for several carboxylases involved in the metabolism of fatty acids, amino acids, and gluconeogenesis, including mitochondrial carboxylases in hair roots [37]. It also plays significant roles in cell signaling, histone modifications, gene regulation, and protein synthesis, particularly keratin production, which is essential for maintaining healthy nails and hair [37]. Biotin is found in various foods and produced by normal gut flora.

Despite biotin’s popularity due to extensive marketing and social media claims about its benefits for hair quality, solid evidence supports its therapeutic use only for treating biotin deficiency. Aside from conditions like alopecia and uncombable hair syndrome, there is no scientific validation of biotin’s efficacy in enhancing hair quality or quantity in individuals without a deficiency [37,38]. Biotin deficiency, which can be inherited or acquired, presents symptoms such as alopecia, eczematous skin rashes, seborrheic dermatitis, conjunctivitis, and neurological issues like depression, lethargy, hypotonia, and seizures [37]. However, in industrialized countries, these deficiencies are rare thanks to sufficient biotin production by intestinal bacteria.

While biotin deficiency can lead to hair loss, there is no conclusive proof that biotin supplements promote hair growth in non-deficient individuals [38]. Randomized controlled trials are still needed to provide sufficient evidence that biotin supplementation prevents or treats hair loss.

3.2.2. Wasabi

Wasabi, a plant native to Japan, is notable for its high content of 6-Methylsulfinylhexyl isothiocyanate (6-MSITC), a compound with multiple physiological benefits, including neuroprotective, anticancer, antidiabetic, and antiallergenic properties [79]. Recent research by Yamada-Kato et al. (2018) reported for the first time the 6-MSITC ability of promoting hair growth in cultured human follicle dermal papilla cells (DPCs) [39]. Specifically, the study demonstrated that 6-MSITC significantly enhances DPC proliferation and upregulates VEGF mRNA levels without inducing cytotoxicity at concentrations up to 2 μM in vitro. VEGF is a crucial factor for DPC proliferation and the formation of perifollicular capillaries, suggesting that the upregulation of VEGF by 6-MSITC may facilitate hair growth [39]. These findings indicate that 6-MSITC has promising potential as a hair growth stimulant, warranting further investigation to elucidate the underlying mechanisms.

3.2.3. Vanyline

Vanillyl butyl ether (VBE) is a warming agent that induces a mild, long-lasting heat sensation when applied and in perspective can promotes hair growth by enhancing microcirculation and stimulating key neurotransmitters [40]. By binding to the vanilloid receptor-1 (VR-1) it activates sensory neurons, generating an electrical signal that triggers the release of neurotransmitters like glutamate, ATP, and calcitonin gene-related peptide (CGRP) [41]. CGRP acts on vascular endothelial cells to induce vasodilation and increase blood circulation. Enhanced dermal microcirculation is essential for hair maintenance, as it delivers growth factors, nutrients, cytokines, and other bioactive molecules while removing waste products [42]. This circulatory support during the anagen phase is linked to the high metabolic activity of hair follicle (HF) matrix cells; insufficient blood supply can lead to HF diseases [42]. Through this mechanism and the stimulation of CGRP release, vanillyl butyl ether can help to prevent hair loss by increasing insulin-like growth factor (IGF-2) production, crucial for hair stem cell proliferation. Further investigation of the modulating mechanisms of these VBE may be useful for the development of hair growth treatments.

3.2.4. Shikimic Acid

Shikimic acid (SA), a compound originally extracted from Japanese and Chinese star anise (Illicium anisatum and Illicium verum), is now sourced from various plants [43]. Known for its antimicrobial, antioxidant, anti-inflammatory, and analgesic properties, SA has recently gained attention for its role in tissue regeneration, particularly due to its presence in plant stem cells (callus), which are essential for plant injury repair [43]. Recently, Choi et al. demonstrated for the first time that SA can promote tissue regeneration, showing promising hair growth effects in both ex vivo human hair follicles (HFs) organoids and in vivo without any evident adverse side effects [43]. Given these findings and the need for long-term treatments in hair loss, SA presents a promising alternative to conventional stem cell therapies of animal origin, which are often associated with side effects and application challenges. Therefore, as a plant stem cell extract, SA stands out as a potential alternative to animal-derived stem cell treatments for hair loss, offering advantages in safety, accessibility, and efficacy. Notably, SA has been shown to induce mRNA expression of critical growth factors like insulin-like growth factor (IGF)-1, keratinocyte growth factor (KGF), and vascular endothelial growth factor (VEGF) in mouse hair follicles [44]. As a mannose bioisostere, SA can interact with the mannose receptor (CD206) expressed on fibroblasts and keratinocytes, potentially enhancing tissue repair, modulating inflammation, and stimulating fibroblast activity—processes critical for hair regeneration and growth. While direct evidence that CD206 receptors on keratinocytes and fibroblasts specifically drive hair regeneration is limited, their role in immune regulation, tissue repair and creating an anti-inflammatory environment likely contribute to hair follicle health and regeneration [45].

3.2.5. Tetrahydroxystilbene Glucoside

Polygonum multiflorum (PM), a traditional Chinese medicinal herb, has long been valued in Eastern Asia for its tonic and anti-aging properties [80]. Among the key bioactive compounds derived from PM root is 2,3,5,4′-tetrahydroxystilbene-2-O-β-D-glucoside (TSG), a stilbene monomer recognized for its diverse biological activities. Among them, radical scavenging and several beneficial effects for the treatment of various conditions, such as neuronal disease, cardiovascular disease, inflammatory disease, and osteoporosis [80]. Traditionally, PM has been used to treat conditions related to hair aging, and recent research has further highlighted its potential in this area [46,47]. Notably, Han et al. and Li et al. demonstrated that PM root extract could restore black pigmentation in hair-fading 57BL/6 mice by reactivating MC1R and tyrosinase [46,81].

Clinical trials have provided further support for the benefits of PM. In double-blind, placebo-controlled studies, significant improvements in hair quality were observed among 26 pre- and postmenopausal women after 3 to 6 months of treatment with PM root extract. Specifically, 97% of participants (25/26) reported reduced hair loss, and 77% noted a significant increase in hair thickness [46]. Another study involving 48 participants (24 = women; 24 = men) aged 30–60 with various causes of hair loss found that 91% of men and 87% of women experienced improvement after just one month of treatment with PM root extract, with no reported side effects [46].

These findings suggest that PM root extract holds promise as an active ingredient in treatments targeting early hair graying and hair loss. However, further clinical research on a larger scale is necessary to confirm these effects and fully establish its efficacy. In this context, it is noteworthy that novel and potentially effective combinations involving tetrahydroxystilbene derivatives are currently under active investigation. For example, European Patent Application EP 24216436.6, describes a formulation comprising 2,3,5,4′-Tetrahydroxystilbene 2-O-β-D-Glucoside in combination with copper compounds, aimed at enhancing bioactivity and target-specific efficacy.

4. Oral Care

Maintaining optimal oral health is not merely a matter of hygiene but a fundamental prerequisite for and a pivotal determinant of systemic well-being and longevity [82]. As research continues to elucidate the intricate bidirectional relationship between oral and systemic health, it becomes increasingly evident that prioritizing oral care is essential for disease prevention and overall physiological resilience [83,84]. Emerging scientific evidence underscores that oral infections, particularly periodontitis, serve as a persistent source of low-grade inflammation exacerbating systemic conditions such as cardiovascular disease, diabetes mellitus, artheroslerosis, and respiratory disorders [85,86,87,88,89]. These effects are mediated through mechanisms involving pro-inflammatory cytokines and microbial translocation, which propagate systemic inflammation and exacerbate disease progression [90].

In a period characterized by environmental pollution and immune challenges, the biochemical composition of oral care formulations is more critical than ever. Bioactive compounds and microbiome-supportive ingredients help counter oral dysbiosis, support teeth remineralization, strengthen mucosal immunity, and prevent systemic inflammation [48,90,91,92]. Given the growing prevalence of inflammatory and immune-mediated diseases, integrating evidence-based oral care strategies is essential for preserving systemic health and promoting longevity [93].

Beyond its implications for systemic health, oral care also significantly influences psychosocial well-being. Advances in dental technologies have revolutionized both cosmetic and restorative treatments, improving not only dental function but also psychosocial well-being [94,95]. An esthetically pleasing smile is associated with increased self-esteem and social confidence, significantly contributing to an individual’s quality of life [96]. Teeth-whitening technologies, such as bleaching agents containing hydrogen peroxide or carbamide peroxide, are extensively used to enhance the visual whiteness of teeth. These agents act by breaking down the chromogenic compounds that cause discoloration, often resulting from lifestyle factors like smoking and the consumption of pigmented foods and beverages [94]. Concurrently, remineralization technologies aim to restore the mineral content of the enamel. Products containing hydroxyapatite, fluorides, and calcium phosphates are formulated to replace lost minerals, enhancing the structural integrity of teeth and preventing dental caries and erosion by reversing the demineralization process induced by acidic environments in the oral cavity [94]. The integration of whitening and remineralization technologies, as well as healthy microbiome-restoring ingredients plays a synergistic role in promoting comprehensive dental health. While whitening treatments address esthetic aspects, remineralization therapies fortify the teeth, making them more resistant to future staining and decay. Additionally, the reestablishment of a balanced oral microbiome supports enamel integrity and overall oral health, reducing the risk of dysbiosis-related conditions. In this context, several natural ingredients have gained attention for their potential to promote teeth whitening, remineralization, and microbiome balance.

4.1. Naturally Derived Ingredients

4.1.1. Hydroxyapatite

Hydroxyapatite (HAP; Ca₅(PO₄)₃(OH)) is a bioactive and biocompatible material that closely resembles the chemical composition of apatite crystals in human enamel [48]. Numerous in vitro and in situ studies have shown HAP’s effectiveness in remineralizing and preventing caries by strongly adhering to tooth surfaces, plaque components, and bacteria [48]. Additionally, HAP helps relieve dentin hypersensitivity and reduces biofilm formation, making it a versatile agent in oral care [48]. Fluoride toothpastes have limited acceptance due to the risk of fluorosis in children. HAP toothpastes represents a fluoride-free alternative that can penetrate deeper into lesions, leading to results that are equivalent or non-inferior to fluoride toothpastes in terms of remineralizing initial caries lesions and preventing carious lesion development [50,51]. In a randomized double-blind crossover study involving 30 adults, enamel blocks with and without caries lesions were exposed intra-orally to toothpaste containing either 10% hydroxyapatite or 500 ppm amine fluoride. Both formulations significantly enhanced remineralization and reduced lesion depth, with no significant difference between them, confirming comparable efficacy [50]. HAP-containing toothpaste has also proved efficacy in few clinical studies [51]. A double-blind randomized controlled trial in 207 children over 336 days compared fluoride-free hydroxyapatite toothpaste with a fluoride toothpaste for caries development in the primary dentition using International Caries Detection and Assessment System (ICDAS) ≥ code 1. Caries progression was similar between groups (72.7% vs. 74.2% of teeth affected), providing the first evidence in children that hydroxyapatite toothpaste is not inferior to fluoride in preventing enamel caries progression [97]. Another recent randomized double-blind clinical trial in 130 children compared the remineralizing efficacy of fluoride plus hydroxyapatite (Remin Pro^®) and fluoride plus casein phosphopeptide-amorphous calcium phosphate (Mi Paste Plus^®) for white spot lesions in primary enamel. Remineralization was assessed after 10 and 21 days, showing that both treatments produced significant improvements compared with fluoride control (NaF toothpaste), with no significant difference between them. No adverse effects were reported [98]. While the results were promising, the short follow-up suggests that longer observation periods are needed to determine the time frame in which the agents achieve their greatest effect. Further studies comparing these remineralizing agents with other novel biomaterials in primary teeth are warranted.

Enamel loss has also become a prevalent clinical concern in routine dental practice. It arises primarily from erosion, attrition, and abrasion, and is frequently associated with dentine hypersensitivity (DH) across different teeth. The formulation of novel toothpaste technologies offers the potential to enhance preventive efficacy against dental caries [52,53]. Advanced biomimetic zinc–carbonate hydroxyapatite technology has been developed to enhance HAP’s affinity and efficacy by closely mimicking natural enamel and dentin, by creating microcrystals of biomimetic hydroxyapatite that include the main substituents present in our teeth (zinc ion and carbonate ion) [48]. Several studies have confirmed that toothpaste containing biomimetic zinc–carbonate hydroxyapatite effectively remineralizes dental enamel by depositing a hydroxyapatite-rich coating and reduces dentin erosion through mineral deposition onto sound and eroded dentin [48]. In an initial observational clinical trial, a total of 46 patients with subjective dentine hypersensitivity were enrolled and asked to complete a questionnaire using visual analog and Likert scales at baseline and after four weeks of home use of a toothpaste containing biomimetic zinc-HAP. After the intervention, subjective dentine hypersensitivity was significantly reduced. Patients also reported smoother tooth surfaces, whiter tooth color, and a greater sensation of freshness compared with their previously used toothpaste. These results further confirmed the efficacy of zinc-HAP toothpaste to reduce the subjective symptoms of dentine hypersensitivity (e.g., induced by cold, sweet, and/or acid stimuli) [99]. Based on current evidence, products containing zinc–carbonate hydroxyapatite represent a promising alternative to fluoride for caries prevention and enamel remineralisation, while also contributing to the reduction in dentine hypersensitivity. However, further clinical studies are warranted to confirm these findings and strengthen the evidence base.

4.1.2. Aspartic Acid

Tooth enamel is highly susceptible to demineralization, making effective remineralization strategies essential. Traditional methods often use non-native calcium sources that may not fully restore optimal enamel structure. Biomimetic mineralization, an innovative process that mimics natural biomineralization, has recently advanced with the novel particle-mediated mineralization model [49]. This model focuses on the formation of metastable amorphous calcium phosphate (ACP) nanoprecursors, which are stabilized by non-collagenous proteins (NCPs) found in hard tissues [49].

Aspartic acid (Asp), a key component of NCPs, plays a critical role in the biomimetic remineralization of demineralized dentin, promoting the crystallization kinetics of metastable ACP to nano apatite through synergistic effect [49]. This approach results in the remineralization of dentin with mechanical and biological properties potentially resembling natural teeth, accomplished through both internal and external mineralization of collagen fibers.

In contrast, Ivanova et al. (2024) recently observed that Asp alone significantly reduced enamel surface microhardness, indicating demineralization when compared to experimental treatments such as deionized water and fluoride [54]. However, when combined with 1% hydroxyapatite, the remineralization effect was notably enhanced, surpassing the efficacy of both fluoride and deionized water [54]. These findings highlight the potential synergistic benefits of combining Asp with hydroxyapatite in dental applications, which could offer more effective strategies for enamel restoration and tooth health maintenance. To date, both models have only been evaluated through in vitro simulations, and supporting clinical data is still required.

4.1.3. DL–Malic Acid

Malic acid, an organic dicarboxylic acid commonly found in fruits such as pears and apples, impact dental health in several ways [55]. Firstly, malic acid acts as a tooth-whitening agent by oxidizing the surface of tooth enamel. This oxidation process involves the release of free oxygen radicals that target the double bonds of both organic and inorganic compounds in teeth, thereby facilitating the dissolution of stains [55].

Moreover, malic acid interacts with calcium ions within the tooth enamel matrix influencing tooth erosion dynamics and ultimately reducing the surface hardness of the tooth over time [56].

Given its natural origin and multifaceted effects on dental surfaces, malic acid represents a promising candidate for inclusion in oral care products aimed at improving both the esthetic and hygienic aspects of dental health. Further studies are warranted to explore its full potential and optimize its application in dental therapies.

5. Beyond Beauty: The Power of Neurocosmetics

In the previous sections, advances in skin, oral, and hair care have been described mainly in terms of their ability to improve local physical conditions through the use of innovative bioactive ingredients. More recently, however, a growing body of evidence has highlighted that the efficacy of dermatological and cosmetic approaches should also be evaluated in the context of their interactions with the nervous and neuroimmune systems, in order to achieve a more integrated and holistic effect [100,101]. This had led to the emergence of neurocosmetics, a new class of topical formulations designed not only to improve cutaneous structure and function, but also to interact with the skin’s neurosensory system and modulate neuroimmune signaling [101]. By integrating principles of neurobiology and somatosensory modulation, neurocosmetic products aim to influence psychophysiological responses, including stress and emotional balance [100,101]. These advances underscore a conceptual shift from a purely peripheral approach to personal care towards a systemic perspective in which skin and emotional well-being are considered components of the same unit.

Plant adaptogens and extracts such as lavender and chamomile essential oils represent commonly used active ingredients in neurocosmetic formulations [101]. In this light, the therapeutic potential of sensorial interventions such as aromatherapy has received renewed attention. Recent studies indicate that inhalation of essential oils from aromatic herbs can effectively reduce stress, lower blood pressure, and decrease heart rate, thereby promoting both physical and emotional health [60]. Within this broader context, modern medical and psychological practices recognize the intricate interplay between physical, emotional, and mental well-being, with each dimension deeply interconnected in maintaining overall health. Stress and fatigue significantly disrupt both physiological and psychological processes, triggering inflammation, impairing immune function, and disrupting sleep. All these effects increase our susceptibility to anxiety and depression, highlighting the critical balance mind–body between in sustaining health [102]. Maintaining a positive emotional balance has been shown to play a key role in psychological well-being and is increasingly regarded as a determinant of healthy aging [103,104]. For example, a meta-analysis published in the American Journal of Medicine in 2022 reported that individuals with higher levels of positive emotions have a 35% lower risk of developing cardiovascular disease and a 14% reduction in overall mortality [105].

Taken together, these findings emphasize the critical contribution of emotional health to longevity and further support the concept that neurocosmetics may contribute not only to skin homeostasis, but also to improved emotional balance and psychological resilience. Consequently, integrating neurocosmetic strategies into routine personal care may potentially offer a dual benefit, simultaneously targeting dermal function and emotional well-being, and representing a promising frontier in preventive and holistic approaches to health.

5.1. Aromatherapy

Aromatherapy employs volatile compounds from natural sources for treating a spectrum of psychological and physiological disorders [57]. The olfactory system plays a pivotal role in modulating mood, stress, and cognitive function through the physiological effects of aromatic substances. Inhalation of these compounds enables their passage across the blood–brain barrier, allowing interaction with central nervous system receptors, thereby modulating brain function [57,58]. This interaction results in immediate physiological responses, such as alterations in blood pressure, muscle tension, pupil dilation, skin temperature, heart rate, and brain activity, which can define a more relaxed or anxious state [57]. A study on eleven healthy adults investigated the effects of lavender fragrance on mood, physiology, and brain activity. EEG was recorded during three consecutive periods: a 2 min baseline, a 2 min fragrance exposure, and a 2 min post-exposure period. During fragrance exposure, participants held a 100 mL plastic vial containing a lavender-fragranced shower gel approximately 3 inches from the nose, through an opening in the face rest, while breathing normally with eyes closed. Self-report questionnaires administered before and after the session indicated reductions in anxiety and depressed mood, together with an increase in perceived relaxation. Physiological measures showed a decrease in heart rate from baseline to the exposure period, followed by an increase in the post-exposure period. EEG analysis further revealed a shift toward greater relative left frontal activation, a pattern associated with approach-related affect and reduced depressive mood [106].

Accumulating evidence from neuroimaging studies reveals that olfactory stimulation can modulate neural activity in regions associated with mood and emotion, suggesting a tightly interwoven relationship between olfactory pathways and emotional regulation [57,58]. A functional MRI study have demonstrated that exposure to fragrances designed for specific effects (invigorating versus relaxing) leads to differential patterns of brain activation [59]. Seven healthy right-handed young subjects (25.0 ± 2.2 yo, 4 males, 3 females) underwent olfactory fMRI. Images were acquired during execution of the olfactory fMRI paradigm, which consisted of five cycles of alternating rest (45 s) and olfactory stimulation (11 s). The subjects were instructed and trained to breathe normally without sniffing during the study cycle and each subject received olfactory fMRI twice with each fragrance, separated by a 12 min interval. The order of presenting the two fragrances was randomized. fMRI data revealed a widely distributed similar activation in the olfactory and other brain regions. However, invigorating fragrances typically elicit widespread activation in areas linked to emotion, memory, imagery, attention, and motor processing, whereas relaxing fragrances produce significantly weaker activation. The results indicated that a single olfactory stimulus elicited brain activation in multiple systems, suggesting a potential investigation for characterizing emotional neuro-substrate with olfaction-evoked activation [59].

One of the major limitations of EEG studies is the variability in fragrance concentration, as higher concentrations result in greater fragrance density, potentially leading to inconsistent findings across studies. In addition, EEG recording time plays a critical role in ensuring stable and comparable measurements between laboratories. Consequently, it remains unclear whether fragrances exert consistent effects during longer EEG recordings, across different concentrations, and with larger participant samples. In light of these limitations, the standardization and development of common operating procedures for assessing the effects of fragrances on EEG activity are essential. Finally, while several findings emphasize the intricate relationship between olfactory stimuli, brain function, and mood regulation, further research is needed to elucidate the neurobiological mechanisms underlying the effects of aromatherapy and to support the development of innovative therapeutic approaches in this field.

5.1.1. Phytoncides

Immune Function and Stress Management

Forest environments have long been valued for their peaceful atmosphere, scenic beauty, mild climate, and fresh air. In Japan, the practice of forest bathing (“Shinrinyoku”) involves immersive exposure to forest settings, serving as a natural therapeutic intervention for relaxation and stress alleviation [107]. During this practice, comparable to natural aromatherapy, individuals breathe in phytoncides, volatile organic substances released by trees, known for their strong neuroprotective and immunomodulating properties. A systematic review including 13 studies (randomized controlled trials (RCTs), non-equivalent control group designs (non-RCTs), and one-group pretest–posttest designs), was conducted to assess the effects of forest therapy programs on adults’ immune function. Evidence suggests that inhalation of forest-derived aromatic compounds can have an effect stress-induced immunosuppression, potentially restoring immune function and contributing to the rebalancing of neuroendocrine hormone levels [108].

In vitro studies further supported the immunological benefits of phytoncides, demonstrating their capacity to enhance immune surveillance by augmenting natural killer (NK) cell cytotoxicity [107]. This effect is mediated through the increased secretion of perforin, granzymes, and granulysin—key cytolytic proteins crucial for targeting tumor cells and virus-infected cells [107,109]. Notably, the immunoenhancing effects of forest bathing extend beyond immediate exposure, with elevated NK cell activity and numbers persisting for seven to thirty days, a phenomenon not observed in urban environments [109,110]. The results were derived from a clinical study involving thirteen healthy nurses aged 25–43 years, who participated in a three-day/two-night trip to forest environments. On day 1, participants engaged in a two-hour afternoon walk in a forest; on day 2, they walked for two hours each in the morning and afternoon in two different forest areas; and on day 3, the trip concluded with their return to Tokyo. Blood and urine samples were collected on days 2 and 3 during the trip, and again on days 7 and 30 after the trip. After the forest bathing experience participants reported increased NK cell activity as well as the numbers of NK cells expressing perforin, granulysin, and granzymes A/B, and a reduced proportion of T cells and concentrations of adrenaline and noradrenaline in urine, indicating a measurable decrease in physiological stress. Notably, the enhanced NK activity persisted for more than seven days after the trip. The authors highlight that phytoncides, including α-pinene and β-pinene, were detected in the forest air and may have contributed to the observed increase in NK activity [109]. Using the same study design, another group of twelve healthy male subjects aged 35–56 years was recruited. This time, some participants undertook the program in a forest environment, while others completed it in a city setting, where almost no phytoncides were detected. Participants exposed to the forest environment showed the same physiological outcomes as observed in the first study. In contrast, those in the city did not exhibit increases in NK cell activity, NK cell numbers, or expression of intracellular anticancer proteins, nor did they show a decrease in urinary adrenaline concentrations. These findings support the initial assumption that phytoncides may contribute to the physiological effects observed [110]. The exposure to phytoncides was also shown to correlates with lower cortisol levels and enhanced activation of the parasympathetic nervous system, both of which contribute to improved immune function and overall well-being [111,112]. Field experiments were conducted in 24 forests across Japan. In each experiment, 12 participants (280 in total; mean age 21.7 ± 1.5 years) walked in and viewed either a forest or a city area. Salivary cortisol, blood pressure, pulse rate, and heart rate variability were measured in the morning at the accommodation facility before breakfast, as well as immediately before and after the walking and viewing sessions. The results showed a potential correlation between that exposure to forest environments and a reduction in salivary cortisol concentrations, pulse rate, and blood pressure, together with increased parasympathetic and reduced sympathetic nerve activity, compared with city environments [111].

Anxiety Relief and Mood Enhancement

Beyond its immunological benefits, forest bathing has demonstrated profound effects on mental well-being. A study performed in 155 participants (37% with depressive tendencies) indicate that this practice significantly improves mood, reduces blood pressure, and alleviates symptoms of depression, with particularly pronounced benefits in individuals with depressive tendencies [113]. A study conducted in Taiwan involving 16 middle-aged women reported that participation in a two-day forest therapy program was associated with a marked reduction in negative mood states (i.e., fatigue, anger-hostility, and tension) and anxiety, alongside a significant increase in positive mood states such as vigor. Participants also experienced lower stress levels and improved systolic blood pressure [114].

The neurophysiological benefits of forest bathing extend to relaxation, cognitive enhancement, and mood stabilization [115]. Specifically, Matsubara et al. demonstrated that inhalation of Japanese cedar wood essential oil led to increased salivary dehydroepiandrosterone sulfate (DHEA-s) levels in males following cognitive tasks, suggesting its role in mitigating stress during post-task recovery periods. The study involved nine male clerical officers with stable daily workloads, who were either exposed to or not exposed to the essential oil [60]. Additionally, Joung et al. reported that exposure to 60 μL of D-Limonene for 90 s led to significantly increased parasympathetic nervous activity, decreased heart rate, and subjective reports of relaxation in 13 Japanese female university students [61].

Furthermore, exposure to volatile compounds from the essential oil of Abies sibirica lowered arousal levels following visual display terminal (VDT) tasks, as evidenced by changes in heart rates and alterations in brainwave activity in a group of nine healthy men included in the study [62]. This finding underscores the potential of phytoncides in preventing VDT-related mental health disturbances, including sleep disorders, restlessness, and anxiety [62].

Despite their promising potential, current research on phytoncides has some limitations: studies often involve small sample sizes and lack robust evidence demonstrating a clear causal relationship between phytoncide exposure and observed biological effects. Furthermore, a deeper understanding of the underlying biological and molecular mechanisms through which phytoncides exert their effects is still needed.

Still, incorporating phytoncides into cosmetic formulations—whether through essential oil infusions or bioidentical scent delivery—offers a novel strategy for enhancing relaxation, supporting immune function, and fostering emotional balance. These advancements underscore the potential of neurocosmetic applications in bridging the gap between emotional well-being and physiological resilience, reinforcing the growing recognition of holistic approaches in personal care science.

6. Conclusions and Future Perspectives

In this review, we have examined recent advances in cosmetic science across skincare, haircare, oral care, and the emerging field of neurocosmetics, emphasizing their potential to influence not only external appearance but also physiological resilience and emotional well-being.

In summary, recent advancements in cosmetic science signal a pivotal shift from a narrow emphasis on external esthetics to a more holistic approach that embraces both internal and external well-being. This integrative perspective aligns with the World Health Organization’s definition of health, as a state of complete mental, physical, and social well-being [116]. By incorporating cutting-edge technologies and bioactive natural ingredients into modern skincare, haircare, and oral care formulations, the field recognizes the profound interdependence of mental and physical health in the aging process. Innovations like aromatherapy and neurocosmetic actives further illuminate the profound link between sensory perception, emotional balance, and physiological health. The continued exploration of advanced delivery systems and multifunctional ingredients ensures that cosmetic products go beyond enhancing appearance, actively contributing to systemic health, stress resilience, and longevity.

At the same time, the current body of evidence is marked by important limitations. Some ingredients, such as ectoine, the combination of Aloe vera extract with trimethylglycine, and hydroxyapatite in oral care, are supported by relatively robust clinical data, including randomized controlled trials, showing improvements in skin hydration, elasticity, barrier repair, and enamel remineralization. In contrast, other promising actives—including acetyl tetrapeptide-5, biotin, andrographolide, as well as wasabi (6-MSITC), vanillyl butyl ether, and DL–malic acid—are primarily supported by in vitro findings, animal studies, or small-scale human trials, limiting their translational value. This discrepancy underscores the need for larger, longitudinal, and well-controlled clinical investigations. In parallel, also the field of neurocosmetics exemplifies both promise and current limitations. To date, most neurocosmetic formulations are in preclinical or early clinical stages. Most studies rely heavily on subjective measures such as self-reported mood, relaxation, or quality of life, endpoints that are vulnerable to placebo effects and influenced by individual variability in neurocutaneous signaling, skin type, microbiome composition, and psychological baseline. Within this area, EEG-based studies require particular caution. Although they provide insight into neural responses to olfactory and sensory stimuli, they remain constrained by small sample sizes, heterogeneous methodologies, and lack of standardization in fragrance concentration and recording protocols. This heterogeneity compromises reproducibility and interpretability. Larger, well-designed, longitudinal studies incorporating multimodal assessments are needed to confirm efficacy and safety and to define the role of neurocosmetics within evidence-based dermatologic and esthetic practice.

Despite these challenges, ongoing research indicates that cosmetic science is gradually evolving beyond esthetics, potentially supporting psychological well-being, and healthy aging. Advances in clinical research, standardization of methodologies, and integration of objective measures are likely to accelerate the transition from preliminary findings to consolidated evidence. In this perspective, cosmetics and neurocosmetics represent not only an area of technological innovation but also a promising field of preventive health, capable of redefining personal care and driving a transformative shift that integrates beauty, well-being, and longevity. As research continues to bridge these realms, the industry is moving toward a more seamless integration of external and internal well-being, where each element reinforces and sustains the other.