Do collagen supplements work against skin ageing?

Collagen supplements work -- a little. Two large meta-analyses, one of 19 studies (n=1125) and one of 26 studies (n=1721), show that daily intake of hydrolysed collagen measurably improves skin elasticity, hydration and wrinkle depth compared with a placebo^1,2. The effects are statistically significant, but modest. The researchers themselves caution that some of the studies have methodological weaknesses and that larger independent studies are needed.

The strongest evidence applies to 2.5 to 10 grams per day for 8 to 24 weeks. In a human study of 69 women (aged 35-55), both 2.5 g and 5 g per day significantly improved skin elasticity after 8 weeks, and in older women that effect persisted for four weeks after stopping. Skin moisture content improved as well, but not significantly enough to be certain³. A review of 11 studies (n=805) describes that same dosage as promising, but states that the optimal amount has not yet been established⁴.

Not every product delivers the same result. A human study of 87 women (aged 40-65) found that collagen combined with vitamin C improved wrinkle severity and skin texture over 16 weeks, but had no significant effect on elasticity or hydration. Adding hyaluronic acid to the supplement provided no additional benefit⁵. Formulation, dose and duration of use therefore genuinely matter.

On the safety side there are no concerns: in all available studies hydrolysed collagen was well tolerated and no serious adverse effects occurred^6,4,3. Do bear in mind that the safety data come largely from short-term studies.

The effects are real, but not spectacular. Claims about dramatic skin rejuvenation go considerably beyond what the studies show^7,8. Moreover, many studies are small, industry-sponsored and conducted almost exclusively in middle-aged women. That is not a reason to dismiss the results, but it is a reason to read them critically.