Does collagen help your joints and your skin?

For joint pain in knee osteoarthritis, oral collagen has a reasonably well-supported positive effect. A meta-analysis of 11 randomised studies (870 participants) shows significant improvement in both pain and joint function. Results did vary considerably between studies. The strongest support is for around 10 grams per day for at least 24 weeks.

Athletes without joint disease also benefit. Multiple double-blind studies show less knee pain at 10 grams per day. One study observed this effect only in people who exercise more than three hours per week. A systematic review of 15 studies also emphasises that collagen works best in combination with exercise, not as a replacement for it.

There are two well-researched variants. Hydrolysed collagen provides small building blocks that can reach cartilage via the bloodstream. Native type II collagen works differently: it dampens inflammatory processes in the joint through the immune system. This distinction is scientifically relevant, but the review covering it comes from researchers with a commercial interest, so independent confirmation is needed.

For the skin, the evidence is more preliminary. Laboratory studies show that hydrolysed collagen can stimulate the production of skin collagen. Smaller studies suggest a reduction in visible signs of ageing. But here too, reviews partly come from commercially involved authors. The skin claims are therefore less well supported than the joint claims.

The picture regarding safety is fairly reassuring. Doses of 10 to 25 grams per day are well tolerated, even with prolonged use, with no reported serious side effects. Large-scale systematic safety research is still lacking, but there are no red flags.