What is collagen?
Collagen is a nutritional supplement made from animal or fish materials. It's rich in amino acids that play an important role in the building of joint cartilage and it may have anti-inflammatory effects. Trials into collagen’s role in treating osteoarthritis give mixed results. Studies into the role of collagen in treating rheumatoid arthritis suggest that it doesn’t have a significant effect in reducing pain and joint inflammation. This hasn’t been consistently reproduced across trials.
- Family:Nutritional supplement
- Scientific name: Collagen hydrolysate
- Other names: Hydrolyzed collagen, purified gelatin, HCP, type II collagen
Collagen is made from beef, pork or fish bones and skins after being processed to make it easier to digest. You can buy collagen capsules from pharmacies and health food shops.
How does it work?
Collagen hydrolysate supplements are rich in a number of amino acids (a group of chemical compounds) that play an important role in the creation of collagen. Type II collagen is one of the main proteins in cartilage.
It’s been suggested that taking collagen hydrolysate can improve the symptoms of osteoarthritis by stimulating your body’s production of joint collagen.
Some studies have suggested that autoimmune diseases like rheumatoid arthritis may be treated by taking a foreign antigen (a substance that causes your immune system to react to it) by mouth, which could dampen down your immune system’s reaction. This is called ‘oral tolerance’. Taking collagen by mouth may introduce some chemicals that cause joint inflammation into your body and create oral tolerance to these antigens, reducing the effects of inflammatory arthritis.
Is it safe?
Collagen is considered to be well tolerated with no major side-effects. Minor side-effects include:
- a feeling of heaviness in your stomach
- mild diarrhoea
There are no well-known drug interactions and we don’t yet know what the best dose of collagen is. Studies have used daily doses of between 1–10 g collagen hydrolysate and 0.1–10 mg of chicken or bovine type II collagen.
Trials for rheumatoid arthritis
Four trials tested collagen against a placebo and one tested it against methotrexate. The trials for involved between 60 and 503 participants with rheumatoid arthritis.
- Type II collagen showed fewer swollen joints, joint tenderness and better walk time in only one of the trials against a placebo.
- Although people in both groups improved in the type II collagen and methotrexate trial, the methotrexate participants showed the greatest improvement.
- There was no evidence of increased side-effects in people taking type II collagen, although trials did report participants withdrawing because they believed the collagen wasn’t improving their symptoms.
Trials for osteoarthritis
In the first trial, 81 participants with osteoarthritis were randomly selected to receive placebo tablets or one of three gelatine (collagen hydrolyse) preparations. Participants in the active treatment groups were treated daily with 10 g of each gelatine product (0.5 g each tablet) for two months.
All three gelatine preparations were significantly better than the placebo in reducing pain at the end of the trial period, but they didn’t cause any radiological or laboratory changes.
The most common side-effect was heaviness in the stomach.
This trial included 389 people with osteoarthritis across 20 sites in the UK, USA and Germany. Participants were randomised to receive either 10 g of collagen hydrolysate or placebo tablets for 24 weeks.
- Collagen hydrolysate had no significant effect on reducing pain and improving physical function in the total study group.
- There was a beneficial effect in participants who had severe symptoms at the start of the study.
- Collagen hydrolysate was relatively well tolerated.
In this trial, 250 people with osteoarthritis of the knee were randomised to receive either 10 g collagen hydrolysate or a placebo daily for six months.
- Those who received collagen reported a greater reduction in pain.
- The most frequently reported side-effects were:
- gastrointestinal effects.
Trial 4 included 29 people with mild to moderate osteoarthritis of the knee. Participants were given either a collagen formulation (Fortigel®) or a placebo for 24 weeks.
At the end of the study, there were no reported differences in the following:
In the final RCT, 52 participants with osteoarthritis of the knee were given 10 mg bioactive undenatured type II collagen or glucosamine hydrochloride plus chondroitin once a day for three months.
- There were no differences in pain or functional scores across the trial, but there were differences at some time points which favoured the collagen group when function was measured in a second way.
- There was no difference in the proportion of reported side-effects between the groups.