The substance makes up about a third of all the protein in the human body, more than any other type of protein in the body by mass. There are 28 different types of collagen, each type categorized based on its amino acid composition. About 90% of the collagen in the body is type 1, which is found in the skin, tendons, internal organs and organic parts of bone, according to Healthline. The vast majority of the remaining collagen in the body is made up of the following types:
- Type 2: Found in the cartilage.
- Type 3: Found in the bone marrow and lymphoid tissues.
- Type 4: Found in the basement membrane (thin sheets of collagen that surround most types of tissues).
- Type 5: Found in the hair and the surfaces of cells.
Where does collagen come from?
The body naturally makes its own collagen by breaking down dietary protein into amino acids. The amino acids are what build the various types of protein in the body, including collagen, according to Shannon Weston, a registered dietitian at the University of Texas Health School of Public Health in Houston.
You get the specific building blocks for collagen by eating a balanced diet of protein-rich foods (chicken, beef, eggs, dairy, legumes, nuts and whole grains, for example) and a variety of fresh produce, according to the Cleveland Clinic. A diet high in fresh vegetables and fruit has the added benefit of providing antioxidants, which protect the body from oxidative stress that can degrade collagen, Weston said. The body's ability to produce collagen naturally decreases as we age, she said, but excess sun exposure, smoking and poor diet can also inhibit collagen production.
Collagen for medical treatment
Arthritis causes the collagen in joints to break down faster than it can be replenished, which results in joint pain and decreased mobility. Scientists have been experimenting with administering collagen for treating arthritis since the 1980s, said Brooke Russell, a microbiologist and professor at the Texas A&M Institute of Biosciences and Technology in Houston. But this method hasn't always proven effective, she said.
A 2017 study published in the Journal of Arthritis found that oral collagen supplements helped relieve pain for patients with osteoarthritis, but collagen wasn't more effective than the existing leading drug treatment for rheumatoid arthritis. A 2016 study published in Nutrition Journal also found that collagen supplements helped relieve pain in patients with osteoarthritis.
However, collagen is not likely to begin regrowing itself to completely reverse arthritis, even after a person takes oral supplements, according to the Arthritis Foundation. On the other hand, surgically inserting collagen into arthritic joints may prove to be a promising treatment for arthritis, according to a 2018 study published in the journal PLOS One.
Collagen has been more successful for treating wounds and has been used to do so for more than 2,000 years, according to a study published in the journal BioMedical Engineering OnLine. The collagen is applied topically, often with other structural proteins and antibiotics, to promote healing and prevent infection.
For example, a 2014 review published in the journal Biopolymers describes how a collagen sponge or gel may be placed over a severe burn. The sponge allows the skin to maintain a moist environment while protecting it from infections, and the collagen acts as a scaffold for the regeneration of cells and production of new collagen.
Should you take a collagen supplement?
Collagen is a popular ingredient in oral supplements and topical creams, but there is little science to support the effectiveness of such treatments. Some collagen supplements claim that they can improve skin health, provide relief from joint pain, prevent bone loss, boost muscle mass, promote heart health, increase hair and nail strength, improve gut and brain health and aid weight loss, according to Healthline.
Although topical collagen has been shown to be beneficial for treating wounds, "there is little, if any, proven evidence that taking these supplements has any real medical benefit for hair, nails or skin," said Dr. Adelaide Hebert, a professor of dermatology and director of pediatric dermatology at the University of Texas Health Science Center in Houston. Daily use of sunscreen and moisturizer with retinoids, retinol, ceramides or salicylic acid (depending on a person's needs) is a more effective way to keep skin healthy, Hebert said.
"Be skeptical of the health claims surrounding supplemental collagen," Weston echoed. "Science has not fully studied all of these supposed benefits." Additionally, the U.S. Food and Drug Administration (FDA) doesn't regulate collagen supplements with the same stringency as it does drugs, she said. This means that manufacturers of collagen supplements don't have to prove that the supplements are effective or safe before putting them on the market.
The collagen in many supplements (which generally comes from an animal source, such as cow bones or fish skin) has been highly processed, Russell said. This destroys the structure of collagen by breaking it down into peptides, which are short chains of amino acids. The resulting product is called hydrolyzed collagen, which is water-soluble and therefore easier to incorporate into a lotion or easier to dry and put into a tablet.
When considering whether to take a collagen supplement, it is important to first factor in how your diet and lifestyle are affecting collagen production in your body. "Adding a supplement to a poor diet and lifestyle will not have any health benefits," Weston said. "Focus on lifestyle factors and a well-balanced diet, and skip the supplements."