There can be very few people who haven’t heard the words glucosamine and chondroitin in relation to joint health, but what exactly are they and how do they work?

These products are some of the most popular nutritional supplements in the UK. Numerous research studies testify to their popularity and effectiveness. Most indicate that a mixture of glucosamine and chondroitin (pronounced Kondroytin) are the most effective. Glucosamine in its natural form exists in all our joints and muscles, playing a role in the everyday mobility and smooth working of cartilage, tendons and ligaments. It is a major building block of the complex proteins called glycosaminoglycans that in turn form part of the structure of cartilage. It is essential for the production of new cartilage and synthesis of the joint’s oil (synovial fluid), helping to make it thicker and more cushioning. It strengthens the jelly-like centre of intervertebral discs and is also needed for healthy formation of nails, tendons, skin, eyes, bone, ligaments and mucous membranes. Glucosamine sulphate is a substance that is naturally made in the body from a sugar (glucose) and an amino acid (glutamine). Larger quantities are needed when damaged joints are healing and, as production of glucosamine is normally a slow process, it is often in short supply. It is therefore frequently taken orally as a nutritional supplement.

Research
Glucosamine sulphate can improve joint symptoms associated with sports injuries and arthritis by at least 40% and often up to 70% compared with an inactive placebo. A landmark clinical trial compared the effects of glucosamine sulphate (1500mg once daily for three years) versus placebo on the long-term progression of knee osteoarthritis in 212 patients. Those taking placebo showed progressive narrowing of the knee joint space over the three year trial period, while those taking glucosamine sulphate showed no significant loss of joint space. Those receiving glucosamine sulphate enjoyed significant improvements in pain and disability, which was sustained for the three-year duration of the trial; in contrast, those taking placebo experienced a significant worsening of symptoms. The authors concluded that ‘The long-term structure-modifying and symptom-modifying effects of glucosamine sulphate suggest that it could be a disease modifying agent in osteoarthritis’.1 Glucosamine sulphate appears to be at least as effective in reducing joint pain as non-steroidal anti-inflammatory painkillers such as ibuprofen. In a study involving 178 people with osteoarthritis of the knee, those taking glucosamine 1500mg daily for four weeks showed improvements similar to those seen with ibuprofen 1200mg daily, but with fewer side effects. Two weeks after stopping treatment, those who had taken glucosamine had a better residual therapeutic effect than those taking the non-steroidal anti-inflammatory drug.2

safety
No significant side effects were reported. It should not, however, be used in pregnancy, as its effects have not yet been investigated.

Chondroitin
Chondroitin sulphate is closely related to glucosamine and is usually combined with it for additional benefit. The former supplies building blocks for making structural substances known as glycosaminoglycans in joints. It attracts water into joints, which acts as a shock absorber as well as a nutrient transport system. Chondroitin sulphate inhibits enzymes that break down cartilage, while stimulating those involved in the production of structural substances such as proteoglycans, glycosaminoglycans and collagen. Chondroitin sulphate helps to raise blood levels of hyaluronan, a sticky gel that cements joint tissues together.

1Long-term effects of glucosamine sulphate on osteoarthritis progression: a randomised, placebo-controlled clinical trial, Jean Yves Reginster, Rita Deroisy, Lucio C Rovati, Richard L Lee, Eric Lejeune, O L Bruyere, Giampaolo Giacovelli, Yves Henrotin, Jane E Dacre, Christiane Gossett: Lancet 2001; 357: 251-5.
2Efficacy and safety of glucosamine sulphate versus ibuprofen in patients with knee osteoarthritis, Qiu G X, Gao S N, Giacovelli G, Rovati L, Setnikar I: Arzneimittelforschung. 1998 May; 48(5): 469-74.

back to the top »