You must have heard of glucosamine chondroitin by now. Everyone is using it for joint health and strength. It’s supposed to help maintain and heal cartilage after injury and it seems as though athletes and anybody over 40 or 50 are using it. It’s really not a single thing, but a combination of glucosamine and chondroitin sulfate. Now, you can find it naturally in the body, in cartilage and connective tisssue. Glucosamine used in supplements is usually harvested from the shells of shell fish, whilst chondroitin is usually obtained from shark and cow cartilage. Let’s look at what the research says:
Knee Osteoarthritis In a 2006 study, 1583 patients with knee osteoarthritis received 1500 mg of glucosamine daily, 1200 mg of chondroitin sulfate daily, both glucosamine and chondroitin sulfate, 200 mg of celecoxib daily, or placebo for 24 weeks. The primary outcome of the study was a 20% decrease in knee pain from baseline to week 24. What was found was that glucosamine and ch
ondroitin sulfate alone or in combination did not reduce pain effectively in the overall group of patients and not much better than the placebo. However, as a secondary outcome, the combination of glucosamine and chondroitin sulfate may be effective in the subgroup of patients with moderate-to-severe knee pain 
Treatment with chondroitin sulfate was associated with a significant decrease in joint swelling, effusion, or both. A 2008 study was done to evaluate the effect of glucosamine and chondroitin sulfate, alone or in combination, as well as celecoxib and placebo on progressive loss of joint space width (JSW) in patients with knee osteoarthritis. The outcome of this ,was at 2 years, no treatment achieved a predefined threshold of clinically important difference in JSW loss as compared with placebo . In a nutshell, some studies show benefits and others don’t.
Fracture healing In 2013, a rat study was performed on 61 female rats where a unilateral fracture was created in their tibia. They were given daily dosages of 230 mg/kg glucosamine-sulfate and fractures were analyzed during the first, second
and fourth weeks after fracture. The results showed that daily glucosamine-sulfate doses accelerated early phase of fracture repair in the rat tibia, with increased new bone formation and osteoblast lining . Although this study does show some promise, it still needs to be replicated in a human trial.
Bottom line There are obviously many more studies out there. The ones cited were offered as examples of what you could find. Results that are clearly positive, have been done on animals and not humans. The human trials don’t really show a clear benefit of using chondroitin or glucosamine.
When some benefit is observed, it usually is, as much as the placebo. If you just compare to not using anything, it’s easy to fall into the trap of saying it works. But if the placebo is just as effective, then there has to be something else at play. There is anecdotal evidence of it working and being this miracle supplement….just like with anything else. So, if you can afford it and want to try it, go right ahead. Test it out and see if you gain anything from it. You should still talk to your doctor first, before consuming glucosamine/chondroitin supplements.