Of the 16 products we tested, seven didn't contain all that they claimed
U.S. consumers spent $753 million in 2012 on supplements of glucosamine and chondroitin in an attempt to relieve pain and stiffness from arthritis, according to the Nutrition Business Journal. But the scientific jury is still out as to whether those products work. And on top of that, our new tests of 16 widely sold joint supplements found that some contained less chondroitin than they said they did, and two didn’t dissolve sufficiently.
All of the tested products contain a combination of glucosamine salt (either hydrochloride or sulfate) and chondroitin sulfate, ingredients that occur naturally in and around the cartilage that cushions the joints. Some research has suggested that the combination might reduce pain in certain people with osteoarthritis, the degenerative joint disease that affects 27 million Americans. But the evidence is far from conclusive.
In a large, multicenter trial published in 2006, researchers found some evidence that glucosamine and chondroitin alleviated pain in patients with moderate to severe knee osteoarthritis, the most common type. But subsequent studies have not confirmed that finding. And treatment guidelines issued in May 2013 by the American Academy of Orthopaedic Surgeons don’t recommend glucosamine and chondroitin supplements, citing lack of efficacy.
Inside our tests
We bought the supplements online or from stores in the New York area between August and October 2012. We had outside labs test samples representing three lots of each product. To meet our quality criteria, a product had to contain, on average, at least 90 percent of its labeled amounts of glucosamine and chondroitin; pass our dissolution test, based on the test used by the U.S. Pharmacopeia (USP), a nongovernmental standard-setting organization, where applicable (it applies only to tablets and caplets); and fall within acceptable limits for four heavy-metal contaminants: arsenic, cadmium, lead, and mercury. Those limits are set by the Environmental Protection Agency, the USP, and California’s Proposition 65.
All of the products contained their labeled amount of glucosamine. And none contained worrisome amounts of lead or other heavy metals.
But six products—CVS Triple Strength, Finest Natural Triple Strength (Walgreens), Natural Factors Glucosamine & Chondroitin Sulfates, Spring Valley Triple Strength (Walmart), Trigosamine Max Strength, and 365 Everyday Value Extra Strength (Whole Foods)—fell below their claimed levels of chondroitin, averaging only 79 to 87 percent of the labeled amount. A seventh product, Nature Made Triple Flex Triple Strength, averaged only 65 percent of its claimed chondroitin in our tests. The 365 Everyday Value and Trigosamine pills also didn’t dissolve sufficiently, which suggests that their ingredients might not be fully available for absorption in the body. We think there are better choices than those two.
What to consider
Glucosamine and chondroitin have shown a good safety record in studies of up to three years, but they may interact with some drugs, particularly blood thinners. So check with your doctor first if you take warfarin (Coumadin and generic) or another blood-thinning drug. If you get the green light, pick from among the nine that met our quality criteria, listed in the table. At recommended daily doses, most provide about 1,500 milligrams of glucosamine salt and 1,200 milligrams of chondroitin sulfate. People who are allergic to shellfish should consider avoiding glucosamine derived from crustacean shells, a common source.
Keep a daily pain diary to gauge whether the supplements are helping. If you’ve seen no improvement after three months, it’s unlikely that you will, our experts say.
How they stacked up
All of the products in the table below contained their claimed levels of glucosamine hydrochloride or sulfate (defined as at least 90 percent of the labeled amount), and none had worrisome levels of contaminant metals.The products in the top section also met their label claims for chondroitin and dissolved sufficiently. ⁄ Because they fulfilled all of our quality criteria, we think it makes the most sense to choose from among those nine products. Within groups, products are listed in order of cost per day.