Glucosamine sulfate is a dietary supplement commonly used in the treatment of osteoarthritis. It is a type of glycosaminoglycan, which is a naturally occurring major component of joint cartilage and joint fluid. However, it is unclear how it works. The possible effects of glucosamine sulfate in patients with osteoarthritis may be due to its anti-inflammatory activity, the stimulation of proteoglycans, and the decrease in catabolic activity of cartilage cells (chondrocytes), which inhibits the synthesis of substances that damage the cartilage.
Although it is approved as a medical drug in Europe, it is not approved by the U.S. Food and Drug Administration (FDA) for medical use in humans. While its use for treating arthritis appears safe, there is conflicting evidence as to its effectiveness. Some studies have shown that patients benefit from taking it. The OsteoArthritis Research Society International (OARSI) recommends glucosamine as the second most effective treatment in moderated cases of osteoarthritis. For any appreciable difference to become evident, patients must take it every day for at least six weeks. Animal studies suggest that chondroitin sulfate (another glycosaminoglycan), which is sometimes used in conjunction with glucosamine sulfate, may increase its efficacy. Literature for knee arthritis however, suggests that its results were no better than those of a placebo. Despite the mixed reviews, because it is a relatively benign treatment, it may be worth trying as one component of the non-operative management of mild to moderate arthritis. It may even be safe for those with shellfish allergies as the allergen is within the flesh of the animal, and glucosamine is derived from the shell.
The typical dosage of glucosamine salt is 1500 mg per day. Dosage recommendations for glucosamine sulfate are set by the manufacturer, and vary widely because the amount of glucosamine present in 1500 mg of glucosamine salt depends on the anion present, and whether the manufacturer included other salts in their calculation.
Edited October 17, 2015