Collagen supplements have become one of the bestselling products in the wellness industry, promising everything from smoother skin to stronger joints. But do they actually work? A major new review of the evidence – pulling together data from 113 clinical trials – suggests that, for some health outcomes, the answer is probably yes. But as ever with nutrition science , the full picture is more complicated. Collagen is a protein the body makes naturally. It gives skin its structure and elasticity,