The chemical glucosamine is a natural component of healthy cartilage and joints. One form of glucosamine, called glucosamine sulfate, adds to the slipperiness of synovial fluid, the lubricant that protects joints. Glucosamine sulfate has been marketed as a treatment for a wide variety of medical conditions, but to date, it has only been proven to help with the symptoms of the degenerative joint disease osteoarthritis, according to MayoClinic.com
Forms
A member of the family of chemicals called glycosaminoglycans, glucosamine naturally occurs in cartilage and synovial fluid. Supplemental forms of glucosamine contain different side groups and include glucosamine sulfate, glucosamine hydrochloride and N-acetyl glucosamine. The various forms might have different effects on the body, but benefits are only evidenced by clinical studies with glucosamine sulfate.
Derivation
Glucosamine supplements can be manufactured from chemicals in a laboratory. Alternatively, they can be extracted from a parent compound called chitin, found in high levels in the shells of oysters, crabs and shrimp. Ground shells from these animals can be used to make glucosamine sulfate.
Uses
Glucosamine supplements, most often in the form of glucosamine sulfate, have been used for various health problems, sometimes with little evidence of effectiveness or safety, according to MayoClinic.com. Glucosamine sulfate has been touted as a remedy for osteoarthritis, rheumatoid arthritis, temporomandibular joint arthritis, diabetes, leg pain, glaucoma, weight loss and chronic venous insufficiency. Athletes sometimes use it as a rehabilitation aid, especially after knee injuries.
Benefits
Clinical evidence indicates that glucosamine sulfate, when taken as a capsule or tablet, can help patients with osteoarthritis to have increased joint mobility and less pain, according to MayoClinic.com. The effects begin about four weeks after starting the supplements. Although some arthritis creams contain glucosamine, there is no evidence that it can penetrate the skin. Glucosoamine sulfate tablets or capsules work best for mild to moderate knee osteoarthritis, and might not work as well for more severe cases or other affected joints. None of the other uses for glucosamine sulfate have been clinically proven to be effective.
Side Effects
Both the Merck Manuals Online Medical Library and MayoClinic.com refer to possible allergic reactions in patients with shellfish allergies who take glucosamine derived from shellfish; however, RxList disputes this, stating that shellfish allergies result from the meat and not the shell, also noting that some evidence shows that people with shellfish allergies can safely take shell-derived glucosamine sulfate. Other side effects of glucosamine sulfate include nausea and diarrhea, headache, changes in the fingernails, skin reactions and insomnia.
Warnings
Because glucosamine is considered a supplement, the Food and Drug Administration does not regulate its production and sales. Some products claim to contain glucosamine sulfate but actually contain glucosamine hydrochloride; other products contain no glucosamine at all.
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