Of all the 20,000 or so different proteins in the human body, there is one that dominates more than any other. Without it, our cells would simply collapse in on themselves, our skeleton and blood vessels would disintegrate and we would be little more than blobs of shapeless tissues. This vital component is collagen, a molecule that defines our existence in a multitude of ways that most of us are blissfully unaware of. According to some research, nearly a third of the proteins in humans and other mammals are composed of 28 different types of collagen, from type I collagen, which is found in skin, to type II collagen, which is found in cartilage. But collagen is not merely a building block. As well as maintaining the structure of our tissues, it plays an active role in distributing signals between cells, helping orchestrate the movement of cells to repair damage in our bodies and even the immune response. Healthcare professionals have long used collagen-based materials to help control bleeding and treat everything from wounds and burns to diabetic ulcers. Most collagen proteins consist of long, spindly, flimsy-looking structures called fibrils, which provide it with the strength needed to anchor cells to one another and glue our bones, cartilage and tendons together and yet the flexibility to still allow for movement and agility. Collagen is particularly omnipresent in our skin, where it helps provide both strength and elasticity, qualities that have given it a reputation as some kind of elixir of youth. For while collagen is at its most abundant in our bodies from childhood through to our early 20s, it suddenly begins to dwindle for reasons we do not fully understand. Between 20 and 30, the body slowly begins to naturally produce less and less collagen with every subsequent year of our lives, with consequences that drive the ageing process, both internally and externally. Because the collagen supply we have is not being refreshed as rapidly, the existing collagen picks up more and more damage. This contributes to the appearance of wrinkles, while over time, our joints, muscles and bones slowly become stiffer, saggier and frailer. The extent to which collagen production slows down varies from one person to another. It can be accelerated through certain lifestyle choices such as smoking, excessive drinking, sun exposure and consuming a diet high in added sugar and ultra-processed foods. This knowledge has created an enormous demand for supplements to try to artificially replenish the collagen we have. Collagen powders, gummies, capsules and drinks have all mushroomed into an industry predicted to be worth £5.85bn by 2027, while collagen-infused coffee has developed into the latest wellness trend. Many skincare brands have been quick to notice the burgeoning popularity of collagen-based products. “Our collagen peptides drinks are the No 1 bestsellers on our platform and they bring a lot of repeat clients,” says Eve Casha, chief scientific officer at London company Dermoi. “Many also contact us to learn more about collagen nutraceuticals for anti-ageing.” Anecdotal reports of the benefits of collagen supplements are easy to find. Influencers (among them Jennifer Aniston and Kate Hudson) and reviewers all describe how they help to plump and smooth the skin, add volume to hair and strengthen nails, but it is hard to get an independent assessment of how effective they really are, as almost all available research is funded by the cosmetics industry itself. Dermatologists do believe there is some evidence that they can help skin health. “I initially thought it was just a scam,” says Gary Goldenberg, an assistant clinical professor of dermatology at the Icahn School of Medicine at Mount Sinai hospital in New York City. “Then we started researching it and there actually is some evidence that they can improve skin tone, skin texture, skin elasticity – which are the things that we lose as we get older.” But before you rush to your nearest health store, Goldenberg points out that not all the collagen supplements being marketed do what they claim. Many regulators, such as the Food and Drug Administration in the US, do not review supplements for safety or effectiveness before they are sold to consumers, while concerns have even been raised about certain collagen products containing heavy metals. He also cautions that merely guzzling a few collagen gummies is not sufficient to counteract poor lifestyle habits such as insufficient sleep or smoking and that people should not expect miraculous outcomes. “It’s not going to make 40-year-olds look like they’re 20 again,” he says. “I think that in itself is the wrong goal. When I talk to my patients about anti-ageing, it’s not about looking younger, it’s really about looking your best at your age.” But because collagen is so ubiquitous in our body, the possible applications are much wider ranging than just skincare. When the Observer asked the clinical data analytics company Phesi to run an analysis of collagen clinical trials from 2010 onwards, just 5% were related to cosmetics. Instead, scientists around the world are more interested in its potential for some of the most serious consequences of ageing, from treating bone diseases to improving wound-healing and regenerating arthritic joints. Over the past five years, this research has been accelerated by an unexpected source: the sports industry. Regenerating rugby players In 2016, the exercise physiologist Keith Baar was contacted by a representative of England Rugby who had heard about some intriguing experiments he was conducting on National Basketball Association (NBA) players. Some years earlier, Baar, a professor at the University of California, Davis, had begun taking cells from athletes who had ruptured their anterior cruciate ligament (ACL) – one of the main ligaments that stabilises the knee – and used these cells to create an ACL replica in the lab. He found that by nourishing the lab-grown ligament with two amino acids, proline and glycine, it strengthened. “We got more collagen within the ligament, which made sense because collagen consists of three amino acids, two of which are proline and glycine,” he says. Baar realised that this approach could be replicated in injured athletes by giving them hydrolysed collagen – a form in which it is broken down into small, easy-to-process particles – before undergoing mild to moderate exercise. Some of the results were remarkable. “We were able to completely reverse this athlete who had a hole in one of their tendons,” he says. “That was really exciting.” Soon, he began advising athletes and nutritionists across sports ranging from the NBA to distance running, table tennis and international rugby, on how collagen supplements could help regenerate bones, tendons and cartilage that have been damaged by the intense strain of training and competition. “There’s been a lot of good feedback from the rugby players,” he says. “Because rugby is an impact sport, you’re trying to regenerate or repair the tissues that have got damaged from heavy training or matches. The England Rugby nutritionist says he’s got athletes who say that collagen has changed their performance and their lives, as far as how their body feels.” Baar is even researching whether incorporating hydrolysed collagen into training programmes could help improve athletic performance. Could boosting the amount of collagen in the joints and ligaments of athletes make a sprinter more explosive out of the blocks? Or help a basketball player leap higher? “We did a placebo-controlled study of our American football team here at UC Davis and the athletes who got hydrolysed collagen actually showed improved markers of performance in terms of how quickly they could develop force,” he says. While exciting, a lot of these findings are yet to be put to the test in a full clinical trial, something that will change very soon. On the other side of the Atlantic, a team of doctors at the Institute of Sports Medicine Copenhagen is currently recruiting elite Danish athletes in either endurance or jumping sports who have injuries resulting from overused tendons, to see whether collagen supplements can aid their recovery and make them more resilient. “Potentially, all athletes with overused tendons can benefit from collagen supplements,” says Christian Couppé, one of the scientists leading the trial. “There are some indications that collagen supplement may speed up recovery, compared with placebo, in overused tendons. Some athletes have claimed that they improved from the intake of collagen. These are some of the reasons why we are performing the present research.” The results will be monitored with interest not just in the sports nutrition world, but by researchers curious to see whether collagen can rejuvenate the same tendons, joints and muscle groups in the very old. Preventing frailty According to the charity Age UK, falls are the most common cause of injury-related deaths in the over 75s, resulting in bone fractures and head trauma. It has been estimated that treating hip fractures that have occurred through falls costs the NHS around £1bn every year. One of the reasons older people are so prone to falls is that the collagen that keeps our muscles and tendons supple in our youth is no longer being replenished, causing it to stiffen over the course of our lifetime. “As we get older, our joints become stiffer,” says Baar. “And so we have a hard time going down the stairs, because our tendons are no longer absorbing shock as well, so you feel all of the bumps.” As a result, scientists at Liverpool John Moores University are currently leading a clinical trial looking at whether giving older people collagen supplements over the course of four months can improve the function of their muscles and tendons, making them less vulnerable to tripping. This might make it sound as if we should take as much collagen as possible, but a maximum daily dose of 15g is recommended. Because the fibrils in collagen are large molecules, it takes time for the body to break them down and an excess can lead to indigestion, bloating and even headaches and fatigue. Additionally, some people can be intolerant to collagen supplements and may have an allergic reaction. Further medical research could shed more light on who might benefit most from collagen and the ideal form and dose to take. Scientists are investigating whether it can also help treat osteoarthritis, the most common joint disease worldwide, a degenerative disease that affects 10% of men and 18% of women over 60. Apart from trying to exercise and taking various painkillers, there is little that doctors can recommend and, aside from joint replacement surgery, there are no cures. Studies have suggested that just as with athletes, hydrolysed collagen may help regenerate the damaged joints. One trial of 120 people in 2018 found that a proportion of those taking collagen saw significant improvements in joint pain and mobility. Norwegian company Hofseth BioCare is running its own trial investigating whether various forms of collagen can help people with mild to moderate osteoarthritis. “Treatment advances for osteoarthritis are lagging behind those for many other musculoskeletal and chronic diseases,” says Crawford Currie, head of R&D at Hofseth BioCare. “Why and how collagen seems to work has not been completely elucidated yet, but our intention is to eventually offer dietary supplementation solutions that are easily available, low-cost, safe and which will have a meaningful effect on quality of life.” For while the popular perception of collagen has long been linked to its uses in the cosmetic industry, these developments could help rethink the way we perceive this remarkable protein and perhaps find even more uses for it across the healthcare world.