Two kinds of peptide are marketed for skin: collagen peptides you swallow, and peptides such as GHK-Cu you apply to the skin. The evidence is very different for each.
Consistent in human trials (with caveats)
Two large meta-analyses of randomised trials (19 trials with 1,125 people; 26 trials with 1,721 people) report better skin hydration and elasticity than placebo. The 2023 analysis found biases in the included trials, so the direction is consistent but the size of the effect is uncertain.
Not yet assessed here
The hub holds one review of GHK and no controlled human trial of a GHK-Cu product yet. A review's summary of cosmetic benefits is not the same as a trial result.
Verdicts reflect only the studies summarised on this site, last reviewed November 9, 2026. See how verdicts are set.
| Study | Design | Peptide |
|---|---|---|
| Pu et al., 2023 | Meta-analysis | Collagen peptides |
| de Miranda et al., 2021 | Meta-analysis | Collagen peptides |
| Asserin et al., 2015 | Human trial (controlled) | Collagen peptides |
| Pickart et al., 2015 | Review | GHK-Cu (copper peptide) |
Pu et al., 2023 · Nutrients · 26 randomised controlled trials; 1,721 participants
Hydrolysed collagen improved skin hydration and elasticity compared with placebo (both p < 0.00001). The size of the hydration effect varied with the source of the collagen and how long it was taken; elasticity did not differ by source.
de Miranda et al., 2021 · Int J Dermatol · 19 randomised, double-blind, controlled trials; 1,125 participants aged 20–70 (95% women)
Pooled results favoured hydrolysed collagen over placebo for skin hydration, elasticity and wrinkles. The authors conclude that taking it for about 90 days is effective at reducing signs of skin aging.
Asserin et al., 2015 · J Cosmet Dermatol · Two placebo-controlled trials plus a lab experiment on human skin samples
Daily oral collagen peptides raised skin hydration after 8 weeks. Collagen density in the dermis rose and fragmentation of the collagen network fell from week 4, and both effects were still present at 12 weeks. In skin samples in the lab, collagen peptides…
Pickart et al., 2015 · Biomed Res Int · Review of research on GHK, a peptide found in human plasma that declines with age
Describes GHK, bound to copper, as supporting wound healing and skin repair, mainly from animal and cell work, and reports that cosmetic products containing it were found to improve skin firmness, elasticity and fine lines. It also reports that GHK can raise…
Educational information only. It is not medical or legal advice, and nothing here is a recommendation to use any peptide. Talk to a clinician before starting a supplement or treatment.