Deposition of plant lipids after single application of a lip care product determined by confocal raman spectroscopy, corneometry and transepidermal water‐loss

OBJECTIVE: Lip treatment products often incorporate oils and waxes in their formulations, and a desired outcome of their use is to prevent lip dryness and roughness as well as help to repair this condition. The objective of this study was to combine confocal Raman spectroscopy with skin capacitance (corneometry) and transepidermal water loss (closed chamber Aquaflux system) measurements, in the evaluation of the degree of moisturization and lip skin penetration of a fruit wax (Rhus vernicula peel cera) and natural oil‐based (Cocos nucifera fruit oil and Olea europea oil) lip care product, following a single application. METHODS: The study was conducted on a total of 15 healthy female volunteers. Instrumental measurements were performed before and 30 min, 2 h and 6 h after a single application of the product. RESULTS: Lip skin barrier function as well as lip hydration were significantly improved and penetration of olive oil was maintained for at least 6 h post product application. The deposition of the three component lipids (berry fruit wax, coconut oil and olive oil) into the stratum corneum after a single application of the lip care product was maintained and data significant for 2–6 h post product application. Lipid deposition was regarded as a positive long‐lasting skin care (depot‐) effect combined with a profound hydrating effect for about 6 h. CONCLUSION: The tri‐method approach taken in this study is deemed relevant and valid for measuring lip hydration offering a complimentary assessment of the barrier function of lip skin and interactive effects of cosmetic ingredients.