What is it?

Chondroitin is a dietary supplement and a vital part of cartilage. Studies have found that taking chondroitin can prevent cartilage breaking down and can also stimulate its repair mechanisms.

Chondroitin has been tested in at least 22 RCTs for osteoarthritis. Evidence is inconsistent but many show that it has significant clinical benefits in reducing pain and painkiller use. Higher quality trials were less likely to show benefit.

  • Family: Nutritional supplement
  • Scientific name: Chondroitin sulphate
  • Other names:CSA, CDS, CSC

Chondroitin is a complex sugar produced from the cartilage of cows, pigs and sharks. You can buy chondroitin capsules from pharmacies and supermarkets. It’s usually sold in combination with glucosamine sulphate.

How does it work?

Chondroitin is found naturally in your body. It’s a vital part of cartilage, giving it elasticity by helping it retain water.

Laboratory studies have found that chondroitin can reduce the activity of enzymes and substances that break down collagen in joints. Other studies have demonstrated that it has several anti-inflammatory properties. Research on animals has found that chondroitin can prevent the breakdown of cartilage and can also stimulate repair mechanisms.

Is it safe?

Side-effects are usually mild and infrequent. They can include:

  • stomach upsets
  • headaches
  • increased intestinal gas
  • diarrhoea
  • rashes.

If you take anticoagulants, you should only take chondroitin under your doctor’s supervision. This is because chondroitin might increase the risk of bleeding. You should also be cautious about taking chondroitin if you have asthma because it might make breathing problems worse.

Most trials have used a daily dose of between 800 mg and 1,200 mg taken in divided amounts.

Chondroitin trials for osteoarthritis

Review article (2007)

In the 19 trials into the use of chondroitin for treating osteoarthritis assessed in this review article, the number of participants ranged from 46–631. The trials lasted between 13–132 weeks.

Sixteen trials compared the potential benefits of chondroitin with that of a placebo. The data from the other three came from conference abstracts, meaning only a summary of results is available or they had poorly defined comparison groups.

  • Twelve trials out of the 16 found that chondroitin was significantly superior to the placebo in relieving pain.
  • Five of the 16 placebo trials investigated the potential beneficial effect of chondroitin on increasing the width of joint space. Most found that chondroitin had a small and insignificant effect, compared to the placebo, on the progression of joint space narrowing.
  • Twelve of the 16 placebo trials found that the chondroitin was more effective than the placebo in terms of reducing painkiller use. The other four trials found that chondroitin and the placebo had similar effects.
  • The number and severity of side-effects reported by participants who received chondroitin was less than or similar to those taking the placebo in most of the trials.
  • Overall, evidence from trials with a good study design in putting participants in treatment groups and trials that used the most suitable statistical methods had lower estimates of effectiveness of chondroitin, particularly in terms of reduction in joint pain.

Trial 1

In this trial, 364 participants received either three 400 mg chondroitin sulphate capsules or one 300 mg avocado soybean unsaponifiable capsule a day for six months.

  • Both groups reported decreased pain and stiffness at the end of the trial and for two months afterwards, but there was no difference between the groups.
  • There was no difference in minor side-effects reported between the groups.

Trial 2

A second RCT randomly assigned 622 participants to receive either one 800 mg sachet of chondroitin sulphate or a sachet of placebo once a day for two years

  • After six months of treatment, those who received chondroitin sulphate reported a greater improvement in pain. Both participants’ and their doctors’ overall assessment suggested that the treatment was effective.
  • There were no differences between groups in stiffness and physical function and no differences between the groups at the end of the study.

Trial 3‡

The 662 participants of this study received one of the following doses three times a day for 24 months:

  • 400 mg chondroitin sulphate
  • 500 mg glucosamine
  • a combination of glucosamine and chondroitin sulphate
  • 200 mg celecoxib (a non-steroidal anti-inflammatory drug)
  • a placebo.

In comparison to the placebo, no treatment demonstrated improvement in pain or function.

Review article (2010)

The authors of the most recent review concluded that chondroitin (on its own or combined with glucosamine) didn’t reduce joint pain to any clinically meaningful extent or change clinical aspects of the joint.