Abstract
Background Sphingomyelin (Sph) is a bioactive phospholipid, and its ingestion is suggested to improve skin conditions. Dairy products are accessible dietary sources of Sph. We investigated the effects of dairy-derived Sph on skin conditions. Methods A randomized, double-blind, placebo-controlled trial was conducted. The participants were healthy adult women aged 30-59 years recruited in Japan, who ingested a tablet containing dairy-derived Sph (23.6 mg/day) or a placebo tablet for 12 weeks. The primary endpoints were skin hydration and transepidermal water loss (TEWL). The secondary endpoint was the subjective perception of skin hydration. Results Overall, 94 participants were enrolled and randomly assigned to two groups (placebo, n = 48; Sph, n = 46). At the end of the intervention, 84 participants remained, and 83 (placebo, n = 44; Sph, n = 39) were analyzed. The increase in skin hydration levels on the upper arm in the Sph group was higher than that in the placebo group. TEWL and subjective perception of skin hydration showed no significant differences between the two groups. The incidence of adverse events was comparable between groups, and no adverse drug reactions were found. Conclusion Intake of dairy-derived Sph is safe and improves skin hydration. Sph-rich dairy products can be used to maintain skin health.