Characterization and Efficacy of Essential Oil-Based Cosmetic Formulations for Acne-Prone Skin

This randomized, placebo-controlled, double-blind clinical in vivo study aimed to evaluate the clinical efficacy of a cosmetic formulation for non-inflammatory acne using essential oils. Fifty-three male participants were divided into four groups: a formulation containing a mixture of four essential oils (4EO), Melaleuca alternifolia (M.a.), nanoemulsion of M. alternifolia (Nanoem.), and a placebo group. The participants applied the formulation daily for 90 days and non-invasive skin imaging techniques were employed to assess the outcomes. Skin microrelief images and reflectance confocal microscopy images were captured in the malar region, and Raman spectroscopy was used to analyze the terpene composition of the essential oils, oil mixture, and nanoemulsion. The results indicated that the nanoemulsion, M.a. essential oil, and 4EO formulation effectively reduced the overall number of comedone and improved follicular hyperkeratinization. The nanoemulsion of M.a. demonstrated the most promising outcomes in reducing comedone areas, especially in the infundibular region. This effect could be attributed to the presence of terpinene-4-ol in the essential oil and the enhanced penetration provided by the nanoemulsion formulation. These findings suggest that cosmetic formulations containing essential oils, particularly in nanoemulsion form, have potential against mild acne. This study contributes to our understanding of the relationship between terpene composition and clinical activity, highlighting the importance of innovative delivery systems.