Oral supplementation of specific collagen peptides has beneficial effects on human skin physiology: a double-blind, placebo-controlled study

Proksch E, Segger D, Degwert J, Schunck M, Zague V, Oesser S · Skin Pharmacology and Physiology

The one place the collagen-peptide literature tested two doses head to head against placebo, and the paper reports that comparison rather than leaving it to be inferred. Skin elasticity, the stated primary interest, improved against placebo by a mean 7% in both the 2.5 g and the 5.0 g arm at 4 and 8 weeks, and the two doses did not differ significantly from each other. Four weeks after the last dose the elasticity advantage remained only in women over 50, a subgroup of nine or more per cell. The three secondary measures were null: skin roughness did not separate at 4 or 8 weeks (p=0.61, p=0.63), nor did transepidermal water loss (p=0.88, p=0.90), and skin moisture moved in the right direction in subgroup analysis without reaching significance.

Population

Women aged 35-55

Intervention

2.5 g or 5.0 g collagen hydrolysate (VERISOL) once daily for 8 weeks

Comparator

Placebo

Limitations

Twenty-three women per arm, so it is underpowered to detect a modest difference between the two doses; a flat result here is weak evidence of a plateau rather than proof of one. Skin rather than joint. The statistics were run by the contract laboratory two of the authors work for. Same Collagen Research Institute co-authorship and GELITA-supplied product as the wrinkle trial, and the same absence of any funding or competing-interests statement.