Glucosamine is an amino-sugar that is naturally produced in humans. It is the key building block in the synthesis of glycosaminoglycans, hyaluronic acid and proteoglycans. These substances are the foundation of many of the body's tissues including tendons, ligaments, cartilage, collagen, basement membranes, mucous membranes of the digestive system, membranes in the respiratory tract, and synovial fluid in the joints. Proteoglycans are proteins that make up the connective tissue of cartilage giving joints their elasticity, strength, and resilience.
Tissues in the joints become damaged when lubricating synovial fluids in the joint spaces lose viscosity. Glucosamine normally synthesized, may be insufficient in quantity for repair. With the loss of cushioning, degeneration of bones and cartilage begins, accompanied by reduced flexibility of the joint. Glucosamine supplementation helps to make the synovial fluid thick and elastic.
Reports of rapid symptomatic response to glucosamine in osteoarthritis may be partially due to the promotion synthesis of cartilage proteoglycans. Glucosamine also stimulates synovial production of hyaluronic acid (HA). HA has anti-inflammatory and analgesic properties, and promotes anabolic behavior in chondrocytes. Concentration and molecular weight is decreased in osteoarthritis; glucosamine supplementation may provide long-term benefits, for repair of joint structures.(1)
Both glucosamine sulfate and glucosamine HCl hydrolyze in stomach acids, separating glucosamine from the carrier. Glucosamine is then readily available for absorption in the small intestine. Glucosamine sulfate is approximately 74 percent glucosamine (dependent on product quality) stabilized with a salt of potassium or sodium.
Glucosamine needs sulfur to be properly utilized; however, the concept that the sulfur components of glucosamine sulfate cross-link with other molecules for structural integrity is not supported by research study. Glucosamine uses the sulfur released from existing stores donated by protein molecules already available in the joint tissue.
Glucosamine appears to act synergistically with chondroitin sulfate without side effects. Chondroitin sulfate inhibits the deleterious effect of degradative enzymes on critical joint components. Manganese, vitamin C, and bromelain may improve effectiveness of glucosamine without the side effects typical to nonsteroidal anti-inflammatory drugs.
500-2,000mg daily.
500mg, 3 times a day.
Capsules, tablets, liquids, and powders often in combination with chondroitin sulfate.
None established
None established
Glucosamine sulfate and hydrochloride.
Glucosamine is easily absorbed from the gastrointestinal tract when taken orally.
There is no known toxicity associated with glucosamine.
Individuals on sodium-restricted diets and those concerned about potassium intake should use glucosamine HCl instead of glucosamine sulfate.
Exercise results in reductions of the blood concentrations of glucosamine.
Some glucosamine products are created from shellfish. No allergic responses have been reported in individuals with a shellfish allergy. Supposedly, glucosamine derived from shellfish is purified and therefore should not cause a hypersensitive response. However, data does not exist to support or deny this claim. Until further information is available, individuals with a shellfish allergy should use glucosamine cautiously or use products that are derived from sources other than shellfish.
Glucosamine induced insulin resistance in skeletal muscle in animal studies.(
2),(
3) It has been determined that glucosamine may lower cellular ATP levels and affect insulin action in fat cells by other mechanisms.(
4) A study has reported that interstitial glucose and insulin levels are not reduced during glucosamine therapy.(
5) To date, no evidence has been found to support that glucosamine has an effect on blood sugar regulation in humans.
Glucosamine is necessary for the biosynthesis of macromolecules including glycolipids, glycoproteins, hyaluronic acid, proteoglycans, and mucopolysaccharides, which are also called glycosaminoglycans (GAGs).
Glucosamine provides anti-inflammatory activity.
A 12-month study demonstrated that glucosamine sulfate has chondroprotective activity, with significant improvement after the first 3 months of therapy.(
6) Results of various studies report that glucosamine sulfate may lead to long-lasting pain reduction and functional improvement by means of increasing anabolic mechanisms, reducing the activity of proteolytic enzymes and by its anti-inflammatory effect.(
7)
Studies report decreased joint noises, pain, and swelling after the administration of glucosamine and chondroitin sulfate in the treatment of TMJ.(
8)
A mixture of glycosaminoglycans, including glucosamine, administered to 40 patients with idiopathic calcium-oxalate nephrolithiasis, reported a significant reduction in the formation of oxalate stone formation.(
9)
Glucosamine availability appears to be rate-limiting for hyaluronic acid synthesis. Administration during the first few days after surgery or trauma can enhance hyaluronic acid production in the wound, promoting swifter healing with potentially diminishing complications related to scarring.(
10)
Glucosamine functions as an anti-inflammatory and studies indicate that supplementation with glucosamine reduced inflammation.(
11),(
12),(
13),(
14) Researchers found that glucosamine sulfate supplementation in patients improved symptoms of osteoarthritis and the arthritis did not progress as rapidly as it did in the placebo group.(
15),(
16) Glucosamine combined with physical training may be beneficial to patients suffering with osteoarthritis.(
17)
Symptoms and Causes of Deficiency
No glucosamine deficiency has been reported in humans.
Glucosamine does not occur in foods. Supplemental sources of glucosamine are derived from chitin, which is the processed exoskeleton of shrimp, lobster, and crab shells.