Americans are buying a lot of glucosamine and chondroitin supplements, which are intended to help ease the pain of or prevent symptoms from arthritis. The problem is that there’s no proof that the pills do any good…and tests from our lab-coated cousins down the hall at Consumer Reports showed that many brands don’t even contain the whole dose claimed on the label.

We spent $753 million on various glucosamine and chondroitin supplements last year. Most of those were for people, but some vets also recommend them once pets hit middle age. The theory is good: the substances in the supplements are also in the joint tissues affected in osteoarthritis. What studies haven’t conclusively proven yet is that taking the substances orally results in any kind of relief from joint pain, or that it helps ease arthritis symptoms or rebuild cartilage.

So maybe it doesn’t matter all that much that out of the 16 brands Consumer Reports tested, seven of them didn’t contain as much chondroitin as they claimed on the bottle. Two of those didn’t dissolve sufficiently, so it’s unlikely that you’d get the full dose by digesting it.

The good news is that this is a supplement that is unlikely to harm you, even if its benefits remain unproven. People who take blood-thinning drugs should check with their doctor before starting any supplements, since there’s a danger that glucosamine and chondroitin could interact with them in nasty ways.

The facts about joint supplements [Consumer Reports]

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