Collagen supplements, which have been growing increasingly popular lately, are purported to improve your skin, hair, and nails, and have "anti-aging" effects. However, while experts note that these supplements are generally safe to take, "the evidence for any benefits has been mixed."

What is collagen?

Collagen is a naturally occurring protein that is found in the human body, as well as several protein-rich foods, such as beans, eggs, and red meat. It is the most abundant protein in the body and makes up a major component of skin, bones, tendons, and muscles.

Collagen also has an important role in several cellular processes, including immune response, cellular communication, and tissue repair.

Although our bodies already produce collagen, "we make less of it as we age," said Uma Naidoo, director of nutritional and lifestyle psychiatry at  Massachusetts General Hospital. Collagen production may also be affected by a lack of sleep or exercise, excessive alcohol consumption or smoking, or "environmental exposures such as too much sunlight."

Reduced collagen production can lead to weakened muscles, joint pain, and can cause your skin to look dry and wrinkled.

What are the benefits of collagen supplements?

Recently, many people have begun taking collagen supplements, which are sold in pill, powder, or topical forms, as a way to treat wrinkles, skin dehydration, and joint pain. These supplements are also sometimes considered "anti-aging" treatments.

"Collagen supplements are thought to work by providing the body with the building blocks it needs to produce more collagen, as well as stimulating the body's natural production of collagen," said Pam Hartnett, a nutrition writer and owner of  The Vitality Dietitians.

According to Naidoo, collagen supplements typically contain "various forms of collagen, amino acids, peptides and additional nutrients like vitamin C and biotin." There is both animal-based collagen and vegan collagen, which usually just contains plant-based ingredients to help boost your natural collagen production.

Although there is still debate about the effectiveness of collagen supplements, "some research suggests that supplementation may improve skin appearance as well as joint mobility," Naidoo said. Other studies have also suggested that marine collagen may benefit skin health, bone regeneration, and wound healing.

However, not all types of collagen supplements may be equally effective. For example, oral supplements are believed to be more effectively absorbed in the body compared to skin serums or creams that are applied to the skin's surface.

In general, Walter Willett, a professor of epidemiology and nutrition at  Harvard T. H. Chan School of Public Health, cautioned that "the evidence for any benefits has been mixed."

"The main justification for collagen supplements has been to reduce the effects of aging on skin and to treat arthritis," he added.

What to consider before taking collagen supplements

Current research suggests that taking between 2.5 and 15 grams of hydrolyzed collagen a day is safe. However, since  FDA does not regulate health supplements, experts recommend speaking to your healthcare provider before incorporating collagen supplements into your daily routine.

For example, "[c]ollagen supplements may cause digestive discomforts, such as bloating, constipation, or diarrhea," said Kathryn Piper, a registered dietitian nutritionist and owner of  The Age-Defying Dietitian. She also noted that "it is unclear whether there are potential risks or negative effects associated with long-term collagen use."

Collagen supplements may also negatively interact with certain medications, such as blood thinners, or increase the risk of bleeding. They may also not be suitable for those with histamine intolerance or mast cell activation syndrome since collagen is fermented, and this process could raise histamine levels.

However, "[c]ollagen is generally considered a safe supplement to [take] daily," Harnett said. "In fact, most studies that found a benefit to collagen supplementation looked at consistent daily intake and none of these studies found significant side effects."

In general, collagen supplements may be effective for some people, but "they are a very expensive protein," Willett said, and similar benefits could be achieved through dietary changes.

If people prefer not to spend money on collagen supplements, they can still boost their body's collagen production naturally by "turning to protein-rich foods such as wild-caught fish, eggs, grass-fed daily, eggs, soy and legumes," Naidoo said. (Austin, USA Today, 3/17; Jaspan, Health, 4/5)