Collagen refers to a family of proteins that are the primary structural component of connective tissues,
such as skin and cartilage, according to Yale University.
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.
Arthritic hands.
Collagen supplements have been shown to help patients with osteoarthritis in a small number of clinical
trials, but collagen doesn't appear to be more effective than the leading drug for treating rheumatoid
arthritis. (Image credit: Shutterstock)
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.
