Effect of collagen supplementation on knee osteoarthritis: an updated systematic review and meta-analysis of randomised controlled trials

Researchers combined results from randomized controlled trials, studies where people are assigned by chance, involving adults with knee osteoarthritis. They compared collagen supplements with placebos or other treatments. Overall, people taking collagen generally reported less knee pain and better daily function. The studies differed in the collagen products, doses, and treatment lengths, so the size of the benefit is uncertain.

What this means for you: Collagen may offer a modest reduction in knee pain, but it is not a cure and has not been shown to rebuild damaged cartilage. It is reasonable to view it as optional rather than a proven replacement for exercise, weight management, or medical treatment.