Glucosamine, chondroitin and MSM are popular dietary supplements for treating symptoms of osteoarthritis – worn joint cartilage. But some products are contaminated with lead, don’t contain listed ingredients, or have inadequate labeling, according recent analyses by ConsumerLab.com. ConsumerLab.com purchased and tested supplements for osteoarthritis for people, as well as products for dogs, cats and horses.
One-third of people who take multiple dietary supplements take a joint health supplement, according to the latest ConsumerLab.com consumer survey. Sales of these supplements exceed $800 million, according to 2010 figures from Nutrition Business Journal. Clinical studies suggest that the combination of glucosamine and chondroitin can reduce moderate to severe knee pain due to osteoarthritis. Chondroitin may also significantly decrease pain due to osteoarthritis of the hands. The evidence MSM’s effects on osteoarthritis symptoms in people remains preliminary.
Among the 21 products for people selected by ConsumerLab.com which contained glucosamine and/or chondroitin, four products (19 percent) failed to pass ConsumerLab.com’s review. A supplement sold by a national chain was contaminated with 13.2 micrograms of lead per daily serving—far exceeding the 0.5 mcg limit set by the State of California (the only state to set a limit), above which a warning label is required. Lead accumulates in the body and, at high levels, can adversely affect the nervous system and increase blood pressure. Children are particularly sensitive to lead and should not be exposed to more than 6 mcg in total per day. Adults can tolerate higher levels of lead, but unnecessary exposure should be avoided. A supplement sold by another national brand was also contaminated with lead, although at a lower level—1.7 micrograms of lead per daily serving.
Two products for people were mislabeled: The most expensive supplement tested (costing over $2 per day) contained only 71.5 percent of its claimed chondroitin and another product lacked a required shellfish allergen warning (its glucosamine is made from crab shell).
In a separate review of products for dogs, cats and horses, three of the six products selected by ConsumerLab.com passed quality criteria. One product contained only 4.5 percent of its chondroitin. Two products for dogs and/or cats contained lead above ConsumerLab.com’s limit (the same used for products for people). Lead was also found in one horse supplement. ConsumerLab.com also looked at pet foods promoted for “mobility” or “healthy joints” but careful review of their labels found they provided relatively little glucosamine and chondroitin.
The Product Review of Joint Supplements (for people) is available online and covers 43 supplements (including 20 approved in ConsumerLab.com’s Voluntary Certification program and one product similar to another that was approved).
The Product Review of Joint Supplements for Dogs, Cats, and Horses is separately available online and covers 12 products (including six approved in ConsumerLab.com’s Voluntary Certification program).