Forms of Glucosamine

An estimated 46 million Americans were informed by a physician in 2006 that they had osteoarthritis, rheumatoid arthritis, gout or lupus, as cited by the U.S. Centers for Disease Control and Prevention. Eighty percent of Americans older than 50 show some radiographic evidence of arthritic changes. A possible contributing cause of osteoarthritis is age-related decline in the body's production of glucosamine, which is pronounced by 50 years of age. Glucosamine is a supplement used to slow down the progress of arthritis and to reduce arthritic pain, although some of its forms are more effective than others.

Glucosamine Sulfate Stabilized with Sodium chloride)

Glucosamine sulfate stabilized with sodium is the most common supplemental form of glucosamine, and usually comes in 500mg capsules or tablets, or dissolved in liquid. Glucosamine, in general, is a natural compound found within the body produced by chondrocyte cells and used to make glycosaminoglycans and proteoglycans, which along with collagen, constitute healthy cartilage. These byproducts of glucosamine also keep the synovial joint fluid viscous, which leads to better lubrication and protection of joints, especially weight-bearing ones.

Glucosamine sulfate stabilized with sodium has been the form used for the vast majority of human clinical trials. This is the form that most researchers believe reduces the progression and symptoms of osteoarthritis and rheumatoid arthritis the best, especially within the knee and hip, according to MayoClinic.com. Most glucosamine sulfate products stabilized with sodium are derived from the exoskeletons of shellfish and may contain some impurities, both of which can lead to uncommon allergic reactions.

Glucosamine Sulfate Stabilized with Potassium chloride)

Glusoamine sulfate can also be stabilized with potassium, although it is not offered as commonly on the market. Because this slightly different form of glucosamine has not been used in clinical trials, statements about its efficacy treating arthritis cannot be made. This form of glucosamine is also mostly derived from the exoskeletons of shellfish and therefore carries the same potential for impurity and allergic reactions.

N-acetyl Glucosamine

Based on previous and current research, the N-acetyl glucosamine form appears not to be effective for treating arthritis in humans and should be avoided for this purpose, according to the "Natural Medicine Journal" of the International Center for Nutritional Research. NAG is different from other forms of glucosamine because it does not have a sulfur or chloride molecule attached to it for stabilization. Instead, NAG has a more complex molecule which causes it to be metabolized differently than other forms of glucosamine. Specifically, NAG is not absorbed mostly intact so it can be used in joints; rather, the intestinal bacteria digest it rapidly and the gastrointestinal tract absorbs it before it can reach cartilage.

Glucosamine Hydrochloride

Glucosamine hydrochloride, or HCI, has the greater concentration of glucosamine in its molecule---83 percent compared to 80 percent for glucosamine sulfate varieties---and has better stability, although it has not shown consistently good results in human clinical studies, according to Prescription2000.com. The debate about glucosamine hydrochloride is whether or not the sulfur portion of glucosamine sulfate is needed and utilized by joint cartilage or not. If not, then future studies may show glucosamine HCl form to be more effective at slowing the progression of arthritis and reducing arthritic pain. Some varieties of glucosamine HCl are now made from vegetable sources instead of shellfish, so any concerns about impurities or allergic reactions are now unwarranted.