Do peptides in skincare actually do anything?

As we age, the skin breaks down collagen and elastin, leading to wrinkles and loss of firmness. That mechanism is well understood. Peptides in skincare try to slow or reverse this process, but whether they actually achieve that when applied to the skin is a different question.

Topically applied peptides fall roughly into four types. Signal peptides try to stimulate skin cells to produce more collagen; this has been demonstrated in laboratory research, but the step to real improvement in humans has not yet been well proven. So-called matrikines, peptides that arise from the breakdown of skin proteins, can either promote or worsen tissue remodelling. Reviews point out that the mechanisms of action are poorly understood. A systematic review also concludes that for many over-the-counter anti-ageing products, including peptides, solid clinical data are simply lacking.

A practical problem is that a peptide only works if it remains stable in the cream, is absorbed through the skin, and becomes active in the right location. Meeting all three conditions simultaneously is difficult, and most products have not been tested for this.

The evidence is somewhat stronger for oral collagen peptides. A randomised placebo-controlled study found greater collagen density in the skin after four weeks and improved hydration after eight weeks. Those effects were maintained up to twelve weeks. However, one of the authors was affiliated with a collagen manufacturer, which may have biased the outcome. This applies to that specific study, not to the broader picture.

In short: there is a biologically plausible reason why peptides could do something, and for oral use some initial positive results are visible. But for peptides in creams and serums, strong clinical evidence is lacking. Until better-designed research is available, the claims on the packaging cannot simply be taken at face value.