Glucosamine

What is glucosamine?
Glucosamine is produced naturally in the body and plays a key role in building cartilage, the tough connective tissue that cushions the joints. As a supplement, it provides the raw material needed by the body to manufacture a mucopolysaccharide (called glycosaminoglycan) found in cartilage. The availability of this nutrient may help support joint health by contributing to the normal processes that maintain healthy cartilage, and may help address the symptoms of osteoarthritis.

It is most often sold as glucosamine sulfate, but is also available as glucosamine hydrochloride, and n-acetyl glucosamine. Although they are all forms of glucosamine, each has a different chemical makeup and may not have the same effects when taken as supplements.

Why is it necessary?
Osteoarthritis causes joint cartilage to lose its elasticity and become stiff which leads to joint discomfort, swelling, and loss of movement. Over time, the body decreases production of glucosamine. It is possible that incorporating daily glucosamine supplements may rectify and replace falling levels in the body and reduce osteoarthritis symptoms, although studies have yielded contradictory results.

One study published in the February 23, 2006, issue of the New England Journal of Medicine concluded glucosamine taken with chondroitin sulfate, an important structural component of cartilage providing a joint’s resistance to compression, benefited those with moderate-to-severe osteoarthritis pain. However, another study published in the British Medical Journal in 2010 found glucosamine, chondroitin sulfate, and the combination of the two did not reduce joint pain.

Despite the debate, Dr. Weil believes that there is sufficient evidence of a positive effect to recommend that people with osteoarthritis try the supplement to see if they experience any benefit.

What are the signs of a deficiency?
People over the age of 50 are prone to developing joint, cartilage, and bone injuries as bone density gradually decreases. Morning stiffness and aching joints which improve with a little movement are a common indication of osteoarthritis, and X-rays are the best way to confirm this condition.

How much, and what kind, does an adult need?
There is no Daily Value recommendation; however, Dr. Weil suggests 1,500 mg of glucosamine (in the form of glucosamine sulfate) daily for those with osteoarthritis.

How much does a child need?
Dr. Weil does not suggest that a child take glucosamine if he or she does not have osteoarthritis. If a child is diagnosed with juvenile osteoarthritis, consult a pediatrician before beginning glucosamine supplementation.

How do you get enough from foods?
It is found in shells of marine animals and in animal cartilage but does not occur naturally in abundance in foods that are commonly eaten in the U.S. Instead, supplements offer a method of acquiring glucosamine in sufficiently high quantity to meet the dosages used in studies that demonstrated a therapeutic effect.

Are there any risks associated with too much?
There are no known risks with taking large quantities, but diabetics should consult their primary physician before taking glucosamine because it may alter glucose levels in the body. Large amounts may also interact with diuretics and blood thinners – if you are on these medications, ask your physician before starting to take supplements.

Are there any other special considerations?

• Some glucosamine supplements are derived from shellfish, so those with shellfish allergies must be cautious and determine the origin of the supplements.
• Glucosamine is not recommended during pregnancy due to a lack of research evidence establishing that the supplement is safe for either expectant mothers or the developing fetus.

Some studies have shown glucosamine and chondroitin sulfate taken together may increase effectiveness in relieving arthritis pain, but more research is needed to establish a clear therapeutic effect. Most studies have shown that glucosamine needs to be taken for 2 – 4 months before its full benefits are realized, although many experience some improvement sooner. Glucosamine can be used safely in conjunction with non-steroidal anti-inflammatory drugs (NSAIDs).

Updated by: Andrew Weil, M.D., and Brian Becker, M.D., on January 10, 2013.