Collagen is a protein that is found in many parts of the body, including the cartilage between bones. Since collagen is made up of amino acids, the building blocks of protein, it has been hypothesized that the body can use the amino acids in collagen supplements to protect and rebuild joint cartilage that has been damaged by osteoarthritis (OA) and rheumatoid arthritis (RA). The research on the effectiveness of collagen in these conditions is mixed but shows promise.
Collagen is known as the most abundant protein in the body. It is the main component of the body’s connective tissues and can be found in skin, bones, cartilage, tendons, and teeth. Tough bundles of collagen, called collagen fibers, support most of the body’s tissues and can be found inside and outside cells.
The word "collagen" comes from the Greek word for glue because it acts as a glue between cells and provides structure to the body's organs. For this reason, a drop in collagen levels in the body will cause the skin to lose its shape. Many people therefore take collagen supplements to preserve their skin health. Similarly, low collagen levels can loosen cartilage and tendons, making them more vulnerable to injuries.
There are 16 types of collagen, with the most common types in the body being:3
These three types of collagen make up 80% to 90% of the collagen in the body.
Collagen supplements also come in three types:
Gelatin and hydrolyzed collagen have been broken down from large proteins to smaller bits.3 When collagen is boiled for a long time, it turns into gelatin. Collagen can be further predigested into its basic amino acids and is called collagen hydrolysate, hydrolyzed gelatin, collagen peptides, or hydrolyzed collagen.
Undenatured collagen is not broken down into smaller proteins or amino acids. Undenatured type II collagen (UC-II) is not intended to be used by the body as a collagen rebuilder.
Collagen type II is most often used to treat pain in osteoarthritis and rheumatoid arthritis. It is usually taken from chickens. It is said to work by causing the body to produce substances that fight inflammation, but this has not been proven. Chicken collagen contains the chemicals chondroitin and glucosamine, which may help rebuild cartilage.
However, studies on supplementing with chondroitin and glucosamine have been mixed, and there is no convincing information on the efficacy of these two chemicals on OA.5
Osteoarthritis (OA), also known as degenerative joint disease, is one of the most common forms of arthritis, affecting more than 32.5 million adults.6 It occurs when the cartilage that protects the joints wears down over time. It is said that collagen supplements may help in rebuilding joints and reduce inflammation in osteoarthritis, but clinical evidence is mixed.
One study showed that when patients with knee osteoarthritis were given acetaminophen and collagen, significant improvements in their joint pain, function, and quality of life were reported.7 This was, however, a small study and included only 39 subjects.
A systematic review focusing on osteoarthritis and cartilage repair found that collagen hydrolysate and undenatured collagen showed some potential as an option for managing osteoarthritis, but further investigation is needed before any definite conclusion on their effectiveness can be made.8
Rheumatoid arthritis (RA) happens when the body’s immune system attacks healthy cells by mistake, causing painful swelling mainly in the hand, wrist, and knee joints. In RA, the lining of the joint becomes inflamed, damaging the joint tissue. Research studying the use of collagen supplements in RA has yielded mixed results as well.
A study that looked at both OA and RA noted that reports of positive results with oral collagen in RA remain controversial, particularly when compared with conventional therapies such as methotrexate, a drug designed to slow down the progression of RA.9 Research into oral collagen for OA in the form of UC-II and partially denatured collagen has shown promise as a pain reliever for those suffering from OA.
However, there are still not enough large and long-term studies to verify the effectiveness of collagen in these conditions. Overall, oral collagen supplementation has achieved some positive results against RA in preclinical and clinical studies.
Side effects vary depending on which type of collagen supplement you take, but they are generally minor overall. Possible side effects include:
People with allergies to fish, shellfish, chicken, or egg should avoid taking collagen supplements since many of them contain these ingredients.
Collagen supplements haven't been tested for safety, so people who are pregnant or breastfeeding should avoid using these products when possible.
The best dosage for collagen supplements has not yet been established, but studies have used daily doses of between 1 g and 10 g of collagen hydrolysate and 0.1 mg to 1 mg of chicken or bovine type II collagen.10
UC-II should be taken in very small doses, usually 20 mg to 40 mg per day, while gelatin and hydrolyzed collagen should be taken in higher doses, 10 gm per day.3
Collagen supplements come in powder, capsules, drink mixes, concentrated elixirs, gummies, and chewable tablets.
Unlike prescription and over-the-counter medications, the Food and Drug Administration (FDA) does not approve dietary supplements like collagen for safety and ability to produce results. Organizations do exist that oversee nutritional supplements like collagen, however. Look for seals of approval from U.S. Pharmacopeia (USP), ConsumerLab, or NSF International to be sure the products are manufactured properly.3
The USP Dietary Supplement Verification Program gives a USP verified mark to products that met the program's strict testing and evaluation criteria.11
If you are looking for collagen that is easy to take, look for hydrolyzed collagen powder. It usually has no flavor or color, unless it is added, and dissolves easily in beverages, smoothies, soups, and sauces. Powdered collagen can be added to drinks or food. It mixes best with cold liquids but can be added to warm or hot liquids as well, although it will need more mixing if added to hot liquids.
Even though collagen is considered a natural supplement, always tell your healthcare provider if you are taking collagen or any other dietary supplements. Collagen has been shown to be helpful for some people in reducing the symptoms of OA and RA. However, more research is needed for collagen to verify its effectiveness and ensure its safety in different people. That said, collagen supplements usually cause very mild effects. It's still important to watch out for side effects and let your healthcare provider know if you experience any changes to your health while on collagen supplements.