The Sustained Effects of Bioactive Collagen Peptides on Skin Health: A Randomized, Double-Blind, Placebo-Controlled Clinical Study

Wang Y, Zhu W, Luo W, Ma Y, Zhou Y · Journal of Cosmetic Dermatology

Dermal density, hydration and transepidermal water loss separated from placebo and were still separated four weeks after the last dose, so the effect did not wash out on the timescale a plasma-peptide explanation would predict. On nearly every measure the gap came from the placebo group deteriorating over the sixteen weeks while the supplemented group held or improved — facial dermal density fell 7.1% on placebo and rose 19.2% on collagen, hydration fell 8.2% and rose 9.2%, and facial dermal thickness fell in both groups, by 11.9% on placebo against 1.3% on collagen, which the authors describe as reduced loss rather than gain. Facial elasticity, epidermal thickness at both sites and upper-arm dermal thickness did not separate.

Population

Healthy women aged 35-55

Intervention

5 g bioactive collagen peptides daily for 12 weeks, followed by a 4-week washout

Comparator

Placebo

Limitations

Skin rather than joint. Three of five authors are employees of Shanghai Meifute Biotechnology; the paper names no funder. 83 were randomised and 77 analysed. The supplemented group had a significantly higher BMI at baseline (p=0.02), which the authors set aside as unlikely to matter without testing whether it did. Around ten measures at four timepoints are compared with no correction for multiplicity.