Glucosamine

Overview

Glucosamine, which is produced naturally in the body, plays a key role in building cartilage, the tough connective tissue that cushions the joints.

A number of scientific studies suggest that glucosamine may be an effective treatment for osteoarthritis (OA). Osteoarthritis is a type of arthritis that occurs when cartilage breaks down and is lost, either due to injury or to normal wear and tear. It commonly occurs as people age. In some studies, glucosamine supplements have decreased the joint pain of OA. Not all studies are positive, however, and several recent ones have not found any positive effect from taking glucosamine. It’s not clear why the studies have different findings, and experts disagree on whether glucosamine is helpful in treating OA.

In the past, some researchers thought glucosamine may actually slow progression of the disease, unlike other current medical treatments for OA. Many people take either acetaminophen (Tylenol) or nonsteroidal anti-inflammatory drugs, such as ibuprofen (Advil, Motrin) and naproxen (Aleve), for OA pain. In addition, some of these drugs can cause stomach upset, cramps, constipation, diarrhea, and in some cases, stomach ulcers.

But so far studies have not shown conclusively that glucosamine helps repair or grow new cartilage, or stops cartilage from being further damaged. Glucosamine is often taken with chondroitin, another supplement thought to be effective in treating OA. Like glucosamine, chondroitin also has conflicting results in studies.

Dietary Sources

There are no major food sources of glucosamine, so people who want to take it must take supplements. Most supplements are made from chitin, the hard outer shells of shrimp, lobsters, and crabs. Other forms of glucosamine are available for people who are allergic to shellfish.

How to Take It

Pediatric

Glucosamine is not recommended for children. It is mainly used to treat osteoarthritis (a condition that affects adults), and its safety for children has not been studied.

Adults

For osteoarthritis: Glucosamine sulfate or hydrochloride, 500 mg, 3 times daily, for 30 - 90 days. Once daily dosing as 1.5 g (1,500 mg) may also be used.

You may need to take supplements on a long-term basis to reduce the pain and inflammation of OA. Talk with your health care provider.

Precautions

Because of the potential for side effects and interactions with medications, dietary supplements should be taken only under the supervision of a knowledgeable health care provider.

Studies suggest that glucosamine is safe, and causes only minor side effects such as stomach upset, heartburn, indigestion, gas, bloating, and diarrhea. If these occur, try taking glucosamine with food. People with peptic ulcers should take glucosamine sulfate with food.

Glucosamine sulfate may contain high amounts of sodium or potassium. People on a restricted diet or who take potassium-sparing diuretics should carefully check the label before taking glucosamine supplements.

People with diabetes should have their blood sugar checked regularly. Glucosamine may cause insulin to work less effectively.

Some glucosamine supplements are made from shellfish, so people with shellfish allergies should check with a health care professional before taking them.

Pregnant and breastfeeding women should not take glucosamine, since it has not been studied for safety in these groups.

Possible Interactions

If you are currently being treated with any of the following medications, you should not use glucosamine or make any adjustments to your medications without first talking to your health care provider.

Nonsteroidal anti-inflammatory drugs (NSAIDs) -- If you take NSAIDs to relive the pain of OA, taking glucosamine may reduce the dose of NSAIDs you need to take. Since NSAIDs can cause stomach bleeding, reducing the dosage can be helpful. Talk to your doctor, however, before starting to take glucosamine, since it can take several months before any improvements are felt.

Blood sugar lowering medications or insulin -- Glucosamine may change the dose needed for blood sugar lowering medications and insulin. If you take these medications for diabetes, talk to your doctor before taking glucosamine.

Supporting Research

Chard J. Glucosamine for osteoarthritis: magic, hype, or confusion? It's probably safe-but there's no good evidence that it works [editorial]. BMJ. 2001;322:1439-1440.

Clegg DO, Reda DJ, Harris CL, et al., Glucosamine, chondroitin sulfate, and the two in combination for painful knee osteoarthritis. N Engl J Med. 2006;354(8):795-808.

Das A, Hammond TA. Efficacy of a combination of FCHG49 glucosamine hydrochloride, TRH122 low molecular weight sodium chondroitin sulfate and manganese ascorbate in the management of knee osteoarthritis. Osteoarthritis Cartilage. 2000;8(5):343-350.

Delafuente JC. Glucosamine in the treatment of osteoarthritis. Rheum Dis Clin North Am. 2000;26(1):1-11.

Herrero-Beaumont G, Ivorra JA, Del Carmen Trabado M, et al., Glucosamine sulfate in the treatment of knee osteoarthritis symptoms: a randomized, double-blind, placebo-controlled study using acetaminophen as a side comparator. Arthritis Rheum. 2007;56(2):555-67.

Huskisson EC. Glucosamine and chondroitin for osteoarthritis. J Int Med Res. 2008 Nov-Dec;36(6):1161-79. Review.

Leeb BF, Schweitzer H, Montaq K, Smolen JS. A metaanalysis of chondroitin sulfate in the treatment of osteoarthritis. J Rheumatol. 2000;27:205-211.

Matsuno H, Nakamura H, Katayama K, Hayashi S, Kano S, Yudoh K, Kiso Y. Effects of an oral administration of glucosamine-chondroitin-quercetin glucoside on the synovial fluid properties in patients with osteoarthritis and rheumatoid arthritis. Biosci Biotechnol Biochem. 2009 Feb;73(2):288-92.

McAlindon TE, LaValley MP, Gulin JP, Felson DT. Glucosamine and chondroitin for treatment of osteoarthritis: a systematic quality assessment and meta-analysis.JAMA. 2000;283(11):1469-75.

Muniyappa R, Karne RJ, Hall G, Crandon SK, Bronstein JA, Ver MR, Hortin GL, Quon MJ. Oral glucosamine for 6 weeks at standard doses does not cause or worsen insulin resistance or endothelial dysfunction in lean or obese subjects. Diabetes. 2006;55(11):3142-50.

National Center for Complimentary and Alternative Medicine. The NIH Glucosamine/Chondroitin Arthritis Intervention Trial (GAIT). J Pain Palliat Care Pharmacother. 2008;22(1):39-43.

Reginster JY, Deroisy R, Rovati LC, et al. Long-term effects of glucosamine sulphate on osteoarthritis progression: a randomised, placebo-controlled clinical trial. Lancet. 2001;357:251-256.

Rindone JP. Randomized, controlled trial of glucosamine for treating osteoarthritis of the knee. West J Med. 2000;172(2):91-94.

Salvatore S, Heuschkel R, Tomlin S, et al. A pilot study of N-acetyl glucosamine, a nutritional substrate for glycosaminoglycan synthesis, in pediatric chronic inflammatory bowel disease. Aliment Pharmacol Ther. 2000;14:1567-1579.

Sawitzke AD, Shi H, Finco MF, Dunlop DD, Bingham CO 3rd, Harris CL, et al. The effect of glucosamine and/or chondroitin sulfate on the progression of knee osteoarthritis: a report from the glucosamine/chondroitin arthritis intervention trial. Arthritis Rheum. 2008 Oct;58(10):3183-91.

Thie NM, Prasad NG, Major PW. Evaluation of glucosamine sulfate compared to ibuprofen for the treatment of temperomandibular joint osteoarthritis: a randomized double blind controlled 3 month clinical trial. J Rheumatol. 2001;28:1347-1355.

Towheed TE, Anastassiades TP. Glucosamine and chondroitin for treating symptoms of osteoarthritis. JAMA. 2000;283(11):1483-1484.

Vangsness CT Jr, Spiker W, Erickson J. A review of evidence-based medicine for glucosamine and chondroitin sulfate use in knee osteoarthritis. Arthroscopy. 2009 Jan;25(1):86-94. Review.

Alternative Names

Introduction

Uses

Osteoarthritis

Results from several well-designed scientific studies suggest that glucosamine supplements may be an effective treatment for OA, particularly OA of the knee or hip. In general, these studies suggest that glucosamine:

• Reduces OA pain
• Improves function in people with hip or knee OA
• Reduces joint swelling and stiffness
• Provides relief from OA symptoms for up to 3 months after treatment is stopped

However, the largest clinical trial so far, the 2006 Glucosamine/Chondroitin Arthritis Intervention Trial (GAIT), sponsored by the National Institutes of Health, showed conflicting and somewhat confusing results. The study of about 1,600 people with OA of the knee found that glucosamine and chondroitin did not reduce pain in the overall group, although it did appear to lessen pain among those with moderate-to-severe OA of the knee. The study has raised questions for further research. Since glucosamine and chondroitin were combined in this study, it is not possible to know what effect glucosamine alone might have. In addition, researchers are now studying whether the glucosamine-chondroitin combination may in fact help those with more severe OA.

A second phase in 2008 looked at some participants who continued with the study for another 28 months. They were tested to see whether glucosamine or chondroitin (together or alone) slowed the loss of cartilage in their knees. They showed no difference in cartilage loss compared with people who took placebo. But all groups -- those taking placebo, those taking both supplements, and those taking only one supplement -- lost less cartilage than expected.

Most studies have shown that glucosamine needs to be taken for 2 - 4 months before it is effective, although you may experience some improvement sooner. Glucosamine and chondroitin can be used along with nonsteroidal anti-inflammatory drugs (NSAIDs) to treat OA.

Inflammatory bowel disease (IBD)

Crohn's disease and ulcerative colitis are two inflammatory bowel diseases marked by chronic, frequent bloody diarrhea. Some preliminary clinical evidence suggests that N-acetyl glucosamine oral supplements or enemas may help improve symptoms of IBD in children who have not improved with standard medical treatment. However, the study was small and lacked a control group, so it is impossible to say whether glucosamine really worked. More research is needed.

Available Forms

Glucosamine is available in oral supplements as glucosamine sulfate, glucosamine hydrochloride, and n-acetyl glucosamine. These products may come in tablet, capsule, and powder forms. It is often combined with chondroitin and sometimes manganese as well. Manganese is a trace element necessary for normal bone health. The total amount of manganese from foods and supplements should not exceed 11 mg per day, but several combination supplements for arthritis (containing glucosamine, chondroitin, and manganese) have more than that. Read labels carefully, and consider choosing a supplement without manganese.

Glucosamine hydrochloride has been reported to be better absorbed by the body.

Glucosamine is also available as an injectable form that your doctor can insert directly into a joint. N-acetyl glucosamine is also available as an enema.