Science of supplementation (3 of 3): Glucosamine: To Take or Not To Take?

For the past three months, I have discussed the latest scientific research in fish oil benefits, the need for protein for muscle growth, and now whether or not to take glucosamine.  In the United States, glucosamine is the most common non-vitamin, non-mineral, dietary supplements used by adults.  That is because America is too fat, and we have lots of achy, painful joints.  But first a quick anatomy lesson on our joints.  We have 206 bones in the human body with about 320 to 360 joints depending on your definition of a joint.  The definition we are going to work with is where two bones come together in the body and have movement/motion.  Each joint will be wrapped in a capsule around the end of the bones where they come in contact.  The end of each bone is covered in a slippery surface known as cartilage and inside the capsule is synovial fluid.  It is this synovial fluid and cartilage where the glucosamine may be beneficial.  Glucosamine is the precursor for glycosaminoglycans (a major component of joint cartilage), so in theory taking glucosamine should help to prevent cartilage degeneration and treat osteoarthritis. But does it work?

After reviewing numerous articles and studies on the efficacy and treatment uses for glucosamine, it still comes down to a 50/50 tie.  Studies at the Mayo Clinic show that available evidence from randomized controlled trials supports the use of glucosamine sulfate in the treatment of osteoarthritis, particulary of the knee.  The study goes on to say that glucosamine sulfate only benefitted those with mild to moderate knee osteoarthritis, but did not do much for the severe cases of OA.  The benefit was usually seen in decreased pain relief, an anti-inflammatory effect, and improved joint function.  Currently the Osteoarthritis Research Society International is recommending glucosamine as the second most effective treatment for moderate OA.

Since glucosamine is a dietary supplement and not a pharmaceutical drug, the US government does not have influence on different combinations, dosages, or forms.  One thing the studies did confirm was that the suggested dose is 1500 mg a day.  Manufacturers have combined glucosamine with hydrochloride, methylsulfonylmethane (MSN), and/or chondroitin to make it more effective or better.  All the studies state that the only beneficial combination is glucosamine sulfate!  The other combinations were no better than a placebo!  Another point was to take it in the capsule or powder form because the liquid form begins to breakdown, and the molecules start changing after the first 24 hours.  So when you buy it at the store, there is no telling what you are getting.

It is in my professional opinion, that glucosamine sulfate has shown to benefit many of my patients in the past 12 years who have had stiff or tight joints.  It has seemed to help them get moving and allow them to strengthen their muscles around the joints.  Pain relief has been noted and many patients swear by it.  My take is that as long as they are moving they will continue to improve overall.

Written by Jeremy Kethley, PT