Glucosamine Sulphate

Ruth McKean BSc, MSc, Pg Dip SRD

Updated to reflect recent studies and findings.

  1. Introduction
  2. What is Glucosamine Sulphate?
  3. What is the evidence for their use as a dietary supplement?
  4. If I decide to take glucosamine and/or chrondition .....
  5. Definitions
  6. References & Links


Osteoarthritis (OA) is thought to be caused by breakdown of the cartilage which cushions the ends of bones. Therefore when cartilage is worn down it can expose the ends of the bones resulting in friction and hence joint pain. OA is a progressive disease associated with factors such as ageing, genetics, obesity and physical injury (sport or otherwise). Often analgesics such as aspirin, paracetamol or anti- inflammatory agents such as ibuprofen or more potent prescriptive drugs are used in the management of osteoarthritis. However, there is widespread belief that supplementation with glucosamine can provide relief from OA knee pain without the side effects these commonly used drug therapies may cause and some research has even claimed glucosamine supplementation may even help regenerated cartilage in the knee.

This article aims to explain what glucosamine is and to present an overview of research which has made this supplement so popular, however it also aims to highlight why so much uncertainty exists as to its true effect.

What is Glucosamine Sulphate?

Glucosamine may prevent the breakdown of cartilage through several mechanisms, it activates chondrocytes (specialised cells in cartilage) to produce more collagen which holds the cartilage tissue together. Glucosamine also pulls water into the cartilage (to maintain the 70% water content of cartilage) producing a gel-like sac providing cushioning and flexibility in the joint. Therefore, in essence, supplementation is thought to magnify the body's natural level of glucosamine.

The supplements are derived from animal tissues; glucosamine is taken from crab, lobster or shrimp shells, although it can also be chemically synthesized. It is typically sold as glucosamine sulphate or glucosamine hydrochloride. Glucosamine is often combined with chondroitin sulphate which is found in and around the cartilage cells and it has been suggested that this supplement, in combination with glucosamine, may help further in repairing some of the damaged joint. Chondroitin sulphate is extracted from animal cartilage such as tracheas or shark cartilage.

What is the evidence?

In 2003 scientists reviewed the reported results of 15 studies using either glucosamine or/and chondroitin on OA of the knee and concluded that supplementation improved joint mobility for 1 in 5 patients and hinted that it may slow narrowing of joint spaces. However, although the authors who reviewed these studies concluded there does appear to be some degree of efficiency of these supplements they did voice concerns with some flaws in all of these studies including poor quality of research, bias due to large company sponsorship, subjective reports of knee pain and a small number of people being tested in the studies.

A further study in the British Journal Sport Medicine (2003) gave subjects with regular knee pain 12 weeks of a glucosamine supplement (2000mg per day). The results suggested that a glucosamine supplement can provide some degree of pain relief and improved mobility in subjects who experience regular, chronic knee pain due to cartilage damage and/or possible osteoarthritis. 88% of the glucosamine group did report less knee pain. However there was no objective improvement between groups in the functional tests and it should be noted that the reduction in knee pain was self reported.

Due to the mounting evidence from the above studies and others suggesting glucosamine and chondroitin, separately or in combination, may be effective in reducing pain and even improving functional ability in patients with knee osteoarthritis an independent trial was set up by the National Centre for Complementary and Alternative Medicine in collaboration with the National Institute of Arthritis in the United States of America. They called the trial ‘The Glucosamine-Chondroitin Arthritis Intervention Trial’ (GAIT) which was the first multi-centre clinical trial which set out to eliminate the major flaws in previous studies and to determine whether glucosamine and chondroitin in combination or taken separately for six months was effective in treating knee pain associated with OA.

The first phase of GAIT concluded that for a sub-set of patients with moderate-severe knee pain, caused by OA, glucosamine combined with chondroitin supplement did show significant pain relief (79% had a 20% or more improvements in knee pain versus 54% in the group not receiving these supplements) but there was lack of response in patients with mild pain. However this pain was subjective and the first phase of this study did not show if the supplements actually slowed the progress of OA. However it did conclude that glucosamine and chondroitin sulphate may be useful for patients with moderate-severe pain but not those with mild pain, but the researcher did also caution that due to the smaller number in the moderate-severe group (354 compared to 1,229 in mild pain group) “these findings should be considered as primary and need to be confirmed by further studies”.

The second phase of GAIT (where those that took place in the first phase where asked if they would like to continue in the study for a further 18 months) looked at whether the supplements slowed the destruction of the cartilage (using X ray data). However the results were not so positive and it was concluded there was no clinically important reduction in structural damage to the knee between the placebo (those not taking the supplements) and any of the supplements after two years. However they did see a slight trend towards improvement in those with milder OA of the knee in those taking glucosamine alone (the research did suggest that perhaps taking both glucosamine & chondroitin together may actually reduce the efficacy of the other) and future research may reveal that those with less severe progression of OA may have the greatest potential benefits with glucosamine. To conclude in the words of the lead researcher of this trial “it would be nice to answer the question definitively but we really couldn’t do that”.

If I decide to take glucosamine &/or chrondition sulphate supplement what do I look for?

  • Consult a doctor to find out if your knee pain is caused by cartilage damage as the majority of studies on glucosamine & chondroitin have only been studied in those with cartilage damage. Athletes with cartilage damage should keep in mind that there is no evidence that this supplement works in athletes with cartilage damage. Therefore its use is mainly due to media reports and 'hear- say' in athletic populations. Check with a sports medicine doctor to see if you have appropriate clinical signs and symptoms.
  • If you have knee pain caused by OA/cartilage damage you can try supplementation but if you don’t experience any difference in symptoms within 3 months, you will probably not get any relief from the supplements. Bear in mind that the self reported evidence for pain relief in the above studies is far stronger than any evidence for slowing down the progression of OA/ structural damage.
  • People who are allergic to the chitin in shellfish from which glucosamine is extracted should be wary. Although, most allergies are caused by proteins in shellfish and not the chitin (the carbohydrate from which glucosamine is extracted) such individuals should consult with their doctor.
  • There has been a concern raised whether glucosamine raises blood sugar levels in diabetics although the recent GAIT study found no evidence in change in glucose tolerance but because it is a possibility and evidence for this is inconclusive so do check with your doctor if you have impaired glucose intolerance or are diabetic.
  • Suggest using 1500mg per day of glucosamine rather than combining with chondroitin as more recent research hints that taking both supplements in combination may interfere with absorption.
  • Choose products that are sold by large well established companies as dietary supplements are poorly regulated; therefore quality of supplements will vary. Make sure the ingredients list indicate just the words glucosamine sulphate/K2CL or glucosamine hydrochloride (HCI).
  • Children, and women who are pregnant or breastfeeding should avoid using glucosamine, as the effects are not known in these populations.
  • As yet minimal side effects appear to be rare. There are a very small number of reports in complementary medicine books and websites. These include skin rashes, headaches, drowsiness and mild stomach symptoms such as diarrhoea and flatulence.
  • The long term effects of these supplements are not known.

Definitions (Oxford Medical Dictionary (1998) & Oxford Dictionary of Chemistry (1996))

Osteoarthritis - A degenerative disease of joints resulting from wear of the articular cartilage. The joints are painful and stiff with restricted movement. It is recognized on x-ray by narrowing of the joint space (due to loss of cartilage). People who suffer from severe cartilage damage of the joints can progress to this degenerative condition.

Chondroitin Sulphate – A combination of a protein and a sugar that forms an important constituent of cartilage, bone and other connective tissues.

Connective tissue - Protects and connects cells or organs. All types of connective tissue contain protein fibres that are either tough or elastic.

Cartilage – A tough connective tissue. In some joints it is the main cushion between the bones. In joints with synovial sacs (see below), it covers the ends of the bones and is called articular cartilage.

Synovial sac- A cushioning bag of lubricating fluid of elastic connective tissue. For example, there is a synovial sac in the knee joint.


Black C, Clar C, Henderson R, MacEachern C, McNamee P, Quayyum Z, Royle P, homas S (2009). The clinical effectiveness of glucosamine and chondroitin supplements in slowing or arresting progression of osteoarthritis of the knee: a systematic review and economic evaluation. Health Technology Assessment; 13 (52):1-148

Blakeley JA & Iberia VEO (2004). Glucosamine & Osteoarthritis. American Journal of Nursing; 104 (2): 54-59.
Braham R, Dawson B, Goodman C (2003). The effect of glucosamine supplementation on people experiencing regular knee pain. British Journal of Sports Medicine; 37:45-49.

Chard J, Dieppe P (2001). Glucosamine for osteoarthritis: magic, hype, or confusion? British Medical Journal; 322: 1439-1440.
McAlindon TE, La valley MP, Gulin JP, Felson DT (2000). Glucosamine and chondroitin for treatment of osteoarthritis. Journal of American Medical Association; 283 (11): 1469-475

Nahin RL, Straus SE (2001). Research into complementary and alternative medicine: problems and potential. British Medical Journal; 322: 161-164.

Ricky F, et al (2003). Structural and symptomatic efficacy of glucosamine and chondroitin in knee osteoarthritis. A comprehensive meta-analysis. Archives of Internal Medicine; 163 (13): 1514-1522.

Rovati L C, Annefeld M, Giacovelli G, Schmid K, Setnikar I (1999). Correspondence: Glucosamine in osteoarthritis. Lancet; 354 (6): 1641-1642.

Sawitzke AD, Shi H, Finco MF, Dunlop DD, Bingham CO 3rd, Harris CL, Singer NG, Bradley JD, Silver D, Jackson CG, Lane NE, Oddis CV, Wolfe F, Lisse J, Furst DE, Reda DJ, Moskowitz RW, Willaims HJ, Clegg DO (2008).The effect of glucosamine and/or chondroitin sulfate progression of knee osteoarthritis: a report from the glucosamine/chondroitin arthritis intervention trial. Arthritis Rheumatism Journal; 58 (10):3183-3191

The joints on Glucosamine (JOG) study: A randomized, double-blind, placebo-controlled trial to assess the structural Benefit of glucosamine in Knee Osteoarthritis On 3T MRI.

Web sites

The Arthritis Foundation

The National (American) Center for Complementary and Alternative Medicine



Back to top

The content within this website is provided by independent third parties, either as part of a feature or through links to other websites. does not accept responsibility for the content of those sites or the accuracy of any information contained within this site.

Copyright © All right reserved.