Uses

Osteoarthritis

Results from several 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 (NIH), showed conflicting and somewhat confusing results. The study of about 1,600 people with OA of the knee found that glucosamine alone, or in combination with 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. Researchers are now studying whether the glucosamine chondroitin combination may help people with more severe OA.

A second phase in 2008 looked at 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. Other studies show that people with OA who took glucosamine (1,500 mg once a day) experienced greater improvement in their condition compared to people who took 100 mg of acetaminophen (Tylenol) 3 times a day.

Most studies show that glucosamine needs to be taken for 2 to 4 months before it is effective, although you may experience improvements sooner. Glucosamine and chondroitin can be used along with NSAIDs to treat OA.

Inflammatory bowel disease (IBD)

Crohn disease and ulcerative colitis are two inflammatory bowel diseases (IBDs) marked by chronic, frequent, bloody diarrhea. Preliminary 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.

Cancer

Preliminary evidence suggests that glucosamine inhibits cancer cell growth. In one study, use of glucosamine and chondroitin was associated with a reduced risk of colorectal cancer after 5 years of follow up. More research is needed.

Dietary Sources

There are no major food sources of glucosamine, so you must get it from 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.

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 mineral 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 may be better absorbed by the body.

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

How to Take It

Pediatric

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

Adults

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

Precautions

Because of the potential for side effects and interactions with medications, you should take dietary supplements 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, nausea, 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. Animal studies show an association between glucosamine levels and insulin resistance.

Some glucosamine supplements are made from shellfish. So people with shellfish allergies should check with a doctor before taking glucosamine supplements.

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

Glucosamine may raise blood pressure and cholesterol levels. See your doctor regularly to have these levels checked while you are taking glucosamine.

There is some concern that glucosamine may increase exacerbations in some people with asthma.

Possible Interactions

If you are 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 doctor.

Warfarin (Coumadin): Glucosamine may increase the blood-thinning effect of Warfarin (coumadin) and may increase the risk of bruising or bleeding, which can be serious. Speak with your physician.

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

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.

Cancer medications such as Doxorubicin, Etoposide, and Teniposide: Glucosamine may negatively interact with these drugs. There is some concern that glucosamine may increase cell growth, which is the opposite of what these treatments are designed to do.

Supporting Research

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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.

Dahmer S, Schiller R. Glucosamine. American Family Physicians . 2008;78(4).

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.

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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.

Kantor ED, Lampe JW, Peters U, Shen DD, Vaughan TL, White E. Use of glucosamine and chondroitin supplements and risk of colorectal cancer. Cancer Causes Control . 2013;24(6):1137-46.

Lee YH, Woo JH, Choi SJ, Ji JD, Song GG. Effects of glucosamine or chondroitin sulfate on the osteoarthritis progression: a meta-analysis. Rheumatol Int . 2010;30(3):357-63.

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.

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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.

Petersen SG, Saxne T, Heinegard D, et al. Glucosamine but not ibuprofen alters cartilage turnover in osteoarthritis patients in response to physical training. Osteoarthritis Cartilage . 2010;18(1):34-40.

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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.

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