NHS GP Dr Amir Khan, known for appearances on ITV's Lorraine and This Morning, has said collagen supplements are marketed as a "fountain of youth" but that "that is not how the body works." Speaking on the podcast of consumer group Which?, he explained that while collagen is the body's most abundant natural protein, providing structural support to skin, joints, and bones, production declines by about 1% every year starting in our 20s.
What Dr Khan said about collagen
Dr Khan said: "It is a cheap substance to make and sell and it's been marketed so well. Collagen is a really abundant protein. When you take it orally, it is broken down by your gut into its component parts. And when it's sold to you, they will say, you know, you're lacking collagen in your skin or your or your bones or your tendons or wherever."
"And this collagen will magically get re-purposed into those places. And that is not how the body works. You cannot direct collagen, the component parts of the collagen to where you want it to be."
Evidence for skin, joints, hair and nails
Dr Khan said the results might not live up to the claims according to scientific studies: "It is a cheap substance to make and sell, and it's been marketed so well that almost, you know, so many people are on it, right? But we don't have the evidence to support the claims that come with that."
He added that getting enough protein in your diet is the best way to get it because "you're not just eating a single substance then you're eating something with lots of other nutrients in." He highlighted oily fish as an example, noting that "everybody's talking about collagen but nobody's talking about being deficient in omega-3 fatty acids which is really common."
Dr Khan has previously highlighted a study from 2025 looking at 23 different randomised controlled trials. He said: "Initially, that data showed that there could actually be an improvement in your skin in terms of hydration and elasticity. But once they pulled out the studies that were funded by the collagen industry, there was no benefit to your skin, your hair, and your nails."
He said collagen might improve health with joint pain and function for people with arthritis, but not for people with healthy joints. "The issue is that people are taking this instead of eating food that contains protein and collagen. I'll take this supplement and I'll be fine. But they're missing out on whole food, which has loads of other nutrients."
Dr Khan's rundown of evidence
For skin, some studies suggest collagen supplements may improve skin hydration and elasticity, and possibly reduce wrinkles slightly, but many studies are small, short-term, and some are funded by the supplement industry, so benefits appear modest rather than dramatic. For joints, there's some evidence collagen may help reduce joint pain, particularly in osteoarthritis or people doing lots of exercise, though effects tend to be small. For hair and nails, evidence is much weaker, with claims everywhere online but high-quality studies limited.
He added: "Collagen supplements are not miracle products. They may offer small benefits for skin hydration and joint symptoms in some people, but expectations should be realistic. If you want to support collagen naturally: stop smoking, wear sunscreen, eat enough protein, vitamin C, and get good sleep — because all of those affect collagen production too."
"Would I spend hundreds a year on collagen? Probably not. But if you've tried it and feel better, the evidence suggests there might be a modest effect, so you carry on it won't cause you harm but can be expensive. Collagen peptides may offer modest benefits for skin and joints in some people. But they're not essential, and lifestyle factors — enough protein, vitamin C, sleep, not smoking, and sun protection — probably matter more."
"If you're expecting collagen peptides to erase wrinkles or transform your appearance… the science simply doesn't support that."
