Effects of a Greek Yoghurt-based Complex on the Human Facial Skin Microbiome

Natural ingredient-containing complexes are used in dermo-cosmetics to ameliorate facial characteristics, yet human experimental approaches and trials demonstrating their efficacy remain limited. This study assessed the effects of a Greek yoghurt-based complex on the human facial skin microbiome.

Thirty-one volunteers (27 females, 4 males; 20-65 years) with stressed facial skin and 15 volunteers (10 females, 5 males) with balanced skin were enrolled in a 28-day clinical study. At baseline, skin swabs were collected from both groups. Participants with stressed skin were treated in a split-face design with a yoghurt-based complex applied to the right cheek and placebo to the left cheek for 28 days, with follow-up sampling on days 7, 14, and 28. Bacterial DNA was analyzed by 16S rRNA gene amplicon sequencing. Bioinformatic analyses assessed microbial composition, diversity, and relative abundance. Baseline differences between skin types and treatment effects versus placebo were evaluated over time.

A lowered microbiota diversity was observed in "stressed" facial skin, compared to the "balanced" group, on day 0. The four most abundant microbiota genera were Corynebacterium, Propionibacterium, Staphylococcus and Actinomyces spp. A significant difference in the relative abundance of these species was noted in the two groups (stressed vs. balanced) at baseline, as well as a consistent increase in mean bacterial diversity after intervention with the yogurt-based complex.

A gradual restoration of the skin's microbial balance essential for a healthy skin function and appearance, was noted following the yoghurt-based complex application.