Cosmetics

Skin is constantly exposed to UV radiation. While topical sunscreens are the main preventative measure, oral photoprotective agents are emerging as promising systemic adjuncts, offering uniform, continuous protection. This study presents the results of two clinical trials designed to evaluate the efficacy of supplementation with a standardized coriander (Coriandrum sativum L.) seed oil (CSO) in mitigating UV-induced skin damage, in comparison with a placebo. The first trial investigated the effects of CSO supplementation on women with reactive skin, assessing UVA+B-induced skin erythema and tumor necrosis factor-alpha (TNF-α) release. The second trial included women of all skin types and, in addition to the outcomes mentioned above, examined UVA-induced lipoperoxidation. Measurements were taken before and after 56 days of supplementation. CSO supplementation led to a significant reduction in UV-induced skin erythema and associated TNF-α levels in both cohorts, with decreases of 11.8% and 24.1% in the reactive skin group and 18.1% and 18.7% in the cohort with all skin types, respectively. In women of all skin types, UV-induced skin lipoperoxidation was reduced by 31.9% at 4 h and by 69.9% at 24 h post-exposure. To the best of our knowledge, this is the first study reporting the photoprotective efficacy of CSO. This finding is attributed to CSO’s high petroselinic acid content and its known anti-inflammatory properties.

Pequi (Caryocar brasiliense) oil is a lipid-rich natural ingredient with potential cosmetic applications, but its time-dependent clinical effects on skin remain underexplored. This study aimed to characterize pequi oil using GC-MS, develop a minimalist serum formulation containing the oil, and evaluate its immediate, short-term, and long-term clinical efficacy, as well as perceived efficacy. A serum with 3% pequi oil (SPO) and a vehicle control (SV) were developed and tested in twenty healthy female participants (22–30 years). Stratum corneum water content, transepidermal water loss (TEWL), and sebum content were measured on the malar region at baseline (t0) and after 2 h (t2h), 7 days (t7d), and 28 days (t28d) of application. Porphyrin count and sebaceous gland activity were assessed at t7d and t28d and skin microrelief at t28d. GC-MS revealed oleic acid (55.89%) and palmitic acid (34.90%) as the oil’s main constituents. SPO reduced TEWL and increased skin hydration at t2h and t28d compared to baseline values (p < 0.05). At t28d, SPO significantly reduced oily spots and porphyrin scores and improved skin microrelief. Long-term perceived efficacy indicated better hydration, oil control, and skin feel compared with SV. These findings suggest that pequi oil reduced sebum content and sebaceous gland activity, thereby enhancing skin barrier function, hydration, microrelief, and hydrolipidic balance, supporting its potential as an effective cosmetic ingredient.

Natural ingredients with soothing and skin-protecting effects are becoming increasingly popular in cosmetic science. Great interest has been directed to birch sap, a nutrient-rich fluid from Betula species. This study aimed to investigate whether birch sap can modulate inflammatory responses and maintain skin barrier functions in both cell and animal models. The polysaccharide composition of birch sap was characterized. TNF-α/IFN-γ-stimulated HaCaT keratinocytes were used to assess the effects of birch sap on inflammatory cytokine expression and activation of MAPK and NF-κB signaling pathways. An in vivo model of chemically induced skin irritation was further used to examine the effects of oral birch sap administration on skin hydration, transepidermal water loss, histological features, and cutaneous blood flow. Birch sap significantly reduced IL-1β, IL-6, and IL-8 expression and attenuated MAPK and NF-κB phosphorylation. In vivo, birch sap improved hydration, reduced transepidermal water loss, epidermal thickening and erythema, and decreased elevated skin blood flow associated with inflammation. These results demonstrate that birch sap provides modulatory effects on inflammation and barrier-supportive effects in both cellular and animal models, suggesting its potential as a naturally derived cosmetic ingredient for promoting skin comfort and maintaining epidermal barrier integrity.