Cosmetics

Human skin lipids form interconnected pools that support barrier integrity, immune balance, and interactions with the environment. The stratum corneum barrier is built from an ordered mix of ceramides, cholesterol, and long-chain free fatty acids, while sebaceous lipids and their breakdown products shape surface properties and the skin microbiome. Hexadecenoic fatty acids are key at this interface. Palmitoleic acid (cis-9 16:1; 16:1 n−7, POA) is enriched in viable epidermis and remains detectable in stratum corneum lipids, whereas its isomer sapienic acid (cis-6 16:1; 16:1 n−10) predominates in human sebum. Together, they influence membrane organization, lipid fluidity, and antimicrobial defense. This mini-review outlines skin lipid composition and function with a focus on POA and then summarizes experimental and preclinical topical evidence suggesting antimicrobial effects, enhanced lubrication properties, protection from oxidative and ultraviolet B (UVB) injury, and enhanced wound repair. It also reviews early clinical findings from oral POA supplementation trials reporting improved hydration, barrier function, and markers of photo-oxidative aging, with exploratory signals for acne in a multi-nutrient regimen. Major POA sources include sea buckthorn pulp oil, macadamia and avocado oils, selected marine oils, ruminant fats, and emerging fermentation-derived products. Robust mechanistic human studies are still needed to define optimal dosing, formulations, and indications.

The cosmetic and personal care industry is increasingly shifting toward plant-derived ingredients that combine multifunctional biological activity with favorable safety and sustainability profiles. Trigonella foenum-graecum L. (fenugreek), a leguminous plant traditionally used in food and medicine, has recently attracted growing attention as a potential cosmetic and cosmeceutical ingredient. This review provides a comprehensive and critical synthesis of current knowledge on fenugreek in the context of skin and hair care applications. First, the phytochemical profile of fenugreek relevant to cosmetics is examined, with emphasis on polyphenols and flavonoids, steroidal saponins, alkaloids (notably trigonelline), and mucilage-rich galactomannans. The biological activities of these constituents are then discussed in relation to key cutaneous and scalp mechanisms, including antioxidant defense, anti-inflammatory and antimicrobial effects, anti-glycation and dermal matrix protection, skin hydration and barrier support, as well as hair growth promotion and scalp health. Particular attention is given to recent in vitro, ex vivo, and emerging clinical evidence supporting anti-aging, moisturizing, and hair-care claims. Current formulation strategies and green extraction technologies enabling the incorporation of fenugreek-derived ingredients into topical products are reviewed, alongside considerations of safety, toxicity, and regulatory status under EU cosmetic legislation. Finally, existing research gaps are identified, highlighting the need for standardized extracts, robust clinical validation, and advanced omics-based approaches. This review highlights fenugreek’s strong potential as a versatile plant-based ingredient in cosmetics, despite remaining understudied in topical applications.

Glycerin is a widely used ingredient in cosmetics due to its cost-effectiveness and safety. While often used to enhance the texture of cosmetics, current research has demonstrated that it improves cutaneous properties such as enhanced skin hydration and moisturization. Due to its widespread use in cosmetics, enhancing the functional capacities of glycerin provides a promising method to improve the effectiveness of numerous cosmetics. Ozonized glycerin has emerged as a novel technology able to enhance glycerin’s effectiveness with reported anti-inflammatory, antibacterial, and antiviral effects. This approach leverages ozone stabilization in glycerin for improved stability and prolonged release to the skin. Clinical application of ozonized glycerin has exhibited lightening of aging spots through promoting skin turnover. The objective of this study was to evaluate the enhanced properties of glycerin when ozonized in terms of skin repair and inflammation. Through topical pretreatment of epidermal 3D wound healing models (13 days) and ex vivo human skin biopsies (4 days), ozonized glycerin was able to improve wound closure, enhance skin barrier and extracellular matrix protein expression, and reduce inflammation. Notably, ozonized glycerin enhanced wound closure by 6.8% compared to glycerin, as well as significantly protecting against LPS-induced elastin degradation (67.7% difference from LPS). These data provide evidence for the use of ozonized glycerin as a new technology to prevent and diminish skin inflammation and improve wound repair.