(See also Overview of Dietary Supplements.)
Glucosamine is a precursor of multiple cartilage constituents. It is extracted from chitin (in shells of crabs, oysters, and shrimp) and is taken in tablet or capsule form, usually as glucosamine sulfate, but sometimes as glucosamine hydrochloride. Efforts are being made to find alternative biorenewable sources including metabolically engineered fungi and E. coli(1). Glucosamine is often taken with chondroitin sulfate.
Glucosamine is claimed to relieve pain due to osteoarthritis, possibly with both analgesic and disease-modifying effects. Mechanism is unknown. Mechanism for glucosamine sulfate may be related to improved glycosaminoglycan synthesis as a result of the sulfate moiety. Dosage of glucosamine in all its forms is 500 mg po tid.
Evidence supports use of glucosamine sulfate from Rotta Research Laboratorium for treatment of mild-to-moderate osteoarthritis of the knee when given for at least 6 mo (2-3). Other formulations still need to be rigorously evaluated. The role of glucosamine sulfate in the treatment of more severe knee osteoarthritis and osteoarthritis in other locations is less well-defined. The Glucosamine/Chondroitin Arthritis Intervention Trial (GAIT), a randomized, double-blinded, placebo-controlled, multicenter clinical trial of 1583 patients with symptomatic osteoarthritis of the knee reported that, alone and in combination with chondroitin sulfate (400 mg tid), glucosamine hydrochloride (500 mg tid) did not reduce pain effectively in the all-patient group. However, an exploratory analysis found pain relief with combination therapy in a subgroup of patients with moderate-to-severe knee pain (4).
A recent review of randomized control trials evaluating the effect of glucosamine on chronic low back pain concluded that data were insufficient to demonstrate or exclude benefits of glucosamine (5).
Allergy (in patients who have shellfish allergy and take forms extracted from shellfish), dyspepsia, fatigue, insomnia, headache, photosensitivity, and nail changes may occur.Patients with chronic liver disease should also avoid glucosamine if possible, because of potential hepatotoxicity when taking glucosamine with or without chondroitin (6).
Liu L, Liu Y, Shin HD, et al. Microbial production of glucosamine and N-acetylglucosamine: advances and perspectives. Appl Microbiol Biotechnol 97(14):6149-6158, 2013.
Wu D, Huang Y, Gu Y, et al. Efficacies of different preparations of glucosamine for the treatment of osteoarthritis: a meta-analysis of randomised, double-blind, placebo-controlled trials. Int J Clin Pract 67(6):585-594, 2013.
Towheed TE, Maxwell L, Anastassiades TP, et al. Glucosamine therapy for treating osteoarthritis. Cochrane Database Syst Rev (2):CD002946, 2005.
Clegg DO, Reda DJ, Harris CL, et al. Glucosamine, chondroitin sulfate, and the two in combination for painful knee osteoarthritis. N Engl J Med 354(8):795-808, 2006.
Sodha R, Sivanadarajah N, Alam M. The use of glucosamine for chronic low back pain: a systematic review of randomised control trials. BMJ Open 3(6). pii, 2013.
Cerda C, Bruguera M, Parés A. Hepatotoxicity associated with glucosamine and chondroitin sulfate in patients with chronic liver disease. World J Gastroenterol 19(32):5381-5384, 2013.