Results of a 12.5 million dollar study:
Glucosamine alone group had the least average joint space width loss of 0.013 millimeters
Chondroitin alone group had an average loss of 0.107 millimeters
Glucosamine plus chondroitin group had an average loss of 0.194 millimeters
Celecoxib group had an average loss of 0.111 millimeters
Placebo group had an average loss of 0.166 millimeters.

In addition to measuring average loss of joint space width, the study also measured the percentage of participants with progression (worsening) of their osteoarthritis—defined as a joint space width loss of more than 0.48 millimeters over the two years. Overall, those with grade 2 (moderate) knee osteoarthritis were least likely to have progression of osteoarthritis compared to those with more severe disease. Approximately 24 percent of participants taking the combination of glucosamine plus chondroitin sulfate showed disease progression, which was similar to placebo, but greater than either glucosamine or chondroitin sulfate alone. The researchers theorize that this may reflect interference in absorption of the two supplements when taken together.

http://nccam.nih.gov/news/2008/092908.htm
http://nccam.nih.gov/research/results/gait/qa.htm#a1

My personal conclusion: just take Glucosamine alone by itself without Chondroitin or Hyaluronic Acid or MSM. It's also the cheapest method. I was told that glucosamine actually gets converted into chondroitin anyway. Also, chondroitin is a really large molecule, so it is difficult to absorb. I read a couple articles saying chondroitin spreads cancer more quickly.

http://malecare.com/prostate-cancer-treatment_26.htm
http://forum.natural-animal-health.c....php?p=928#928

Lots of comments in various books about Chondroitin,
http://www.supplementreference.com/c...n_sulfate.html

But glucosamine is safe to take. I know that sounds like a contradiction, but there are no studies I could find showing glucosamine molecules increase with cancer, only for chondroitin. But logically, I agree, if glucosamine converts to chondroitin then whatever problems are associated with chondroitin should exist with glucosamine.

Most companies who sell glucosamine only contain only a fraction of the actual glucosamine reported, and more than 90% of the capsules and tablets come from China. Only FDA regulated glucosamine guarantees 90%+ glucosamine which you can get at Nutrasense-1,000 capsules, 750 mg capsules, for $95 U.S.

I have decided to stop taking the other stuff and just stick with the Nutrasense glucosamine (three 750 mg per day with meals).

In the Textbook of Natural Medicine 2nd Edition Volume 2 by Michael T. Murray, ND, it says...any direct action of orally administered chondroitin sulfate on cartilage and chondrocytes is not possible. The few clinical studies that have been done with orally administered chondroitin sulfate demonstrate that it is less effective than glucosamine sulfate (32-35). Far more impressive results have been achieved with glucosamine sulfate. Glucosamine sulfate is faster acting and provides much greater overall benefit.