Do Collagen Supplements Help Skin, Hair, Nails and Joints?

A: Some small studies suggest that collagen supplements may have limited benefits, but the evidence is far from definitive, and marketing claims seem to have gotten ahead of the science.

Collagen is the main structural protein in animals — humans included — and plays a vital role in tissues like bones, tendons, ligaments, cartilage and skin. It is also increasingly popular in nutritional supplements, which claim to replenish these same tissues.

Eat more animal collagen in the form of these supplements, and you will enjoy healthier skin, hair and nails, plus soothe creaky joints and support digestive function, their labels promise. The supplements are made from collagen-rich animal tissues that might otherwise be tossed aside by meat processors, like the skin and bones of cattle and pigs, as well as fish scales and skin. The proteins are first denatured to form gelatin and then further broken down into smaller fragments before being incorporated into products like powders, gummies, capsules and protein bars. (Supplements marketed as “plant-based collagen” do not actually contain collagen; they claim to support collagen production with a mixture of amino acids, vitamins and minerals.)

Any possible benefit of a supplement like collagen depends on how it is digested and absorbed in the gastrointestinal tract and whether the products of digestion can end up at target tissues and have a therapeutic effect. Some research has looked at parts of that sequence and hinted at some possible benefits, but the story is far from complete.

Take skin, for example. Collagen is one of the major proteins in the dermis, contributing to its firmness and elasticity, said Dr. Diane S. Berson, associate professor of dermatology at Weill Cornell Medical College in New York City. Starting in our 20s, we begin to lose skin collagen, and it can be further damaged by environmental exposures like sunlight, cigarette smoke and pollution. All this leads to sagging, wrinkling and dryness, Berson said.

But she is not convinced that eating collagen can mitigate these effects. A few studies show that taking collagen supplements for several months can improve skin elasticity, moisture and collagen density, but Berson notes they tended to be small and were sponsored by the companies making the products, increasing the chance of bias in the research.

“I don’t think that I am in a position to pooh-pooh it and say this definitely doesn’t work. But as a physician, I would want to see more evidence-backed science,” she said.

Instead, Berson emphasizes the importance of using sun protection, eating a healthy diet, drinking plenty of water, avoiding cigarette smoke and getting enough sleep — all ways to “care for the collagen you already have, rather than trying to replenish it with supplements,” she said.

There is little research on the effects of consuming collagen on hair and nails. One small study found that it decreased nail breakage, but it lacked a control group for comparison. Another product that includes collagen as one of many ingredients appears to improve hair growth, but it is impossible to say what role it might play in that mixture.

Dr. Leticia Deveza, a rheumatology fellow at Sydney Medical School in Australia, does not routinely recommend collagen supplements for patients with osteoarthritis. “The best evidence available suggests that they have only small effects on joint pain at best, which are unlikely to be meaningful to patients,” she said.

“I do worry that people might rely too much on supplements that have no clearly demonstrated benefits and overlook other important components of osteoarthritis treatment,” like exercise and weight management, she added.

Collagen supplements are also marketed to athletes, but “there’s no evidence to show that taking collagen protein improves your ability to rebuild or heal,” said Stuart Phillips, professor of kinesiology at McMaster University in Ontario, Canada, and an author of a recent International Olympic Committee consensus statement on dietary supplements.

The claims are “largely rubbish,” he said, adding that the supplement industry is not well regulated.