In fact, Americans spent 753 million dollars on these over-the-counter supplements last year alone, according to the Nutrition Business Journal. Victoria Primavera likes to stay active. So when she started feeling achy, she began taking nutritional supplements.
"I still have pain in my joints, but it's not so bad since I've been taking the glucosamine chondroitin," Primavera said.
"Some research suggests that the combination of glucosamine and chondroitin might reduce pain in some people who have osteoarthritis in their knees, but the evidence is still inconclusive. However, we know that a lot of people are buying these supplements, so we wanted to see whether they're getting what they're paying for," Jamie Kopf of Consumer Reports said of the supplements.
Consumer Reports tested 16 popular glucosamine-chondroitin supplements -- evaluating three different samples of each.
First the samples were tested to see if they contained the amount of glucosamine and chondroitin the label indicated.
And they tested for heavy metals, like mercury and lead.
"Our tests show that none of the supplements contained worrisome levels of lead or other toxic metals. And all of the products contained their labeled amounts of glucosamine," Kopf of Consumer Reports said.
But one, Nature Made Triple Flex Triple Strength, averaged only 65 percent of the labeled amount of chondroitin.
Six others averaged 79 to 87 percent.
And of the 16 tested, two did not dissolve sufficiently -- indicating the ingredients might not be fully absorbed in the body. They were the Trigosamine Max Strength and 365 Everyday Value Extra Strength from Whole Foods.
However, nine did meet Consumer Reports' quality criteria. The least expensive: Kirkland Signature Clinical Strength tablets from Costco.
Consumer Reports suggests checking with your doctor before trying joint supplements, particularly if you're taking blood thinners or if you're allergic to shellfish. Glucosamine is often made from shrimp shells, and it can increase the effects of blood thinners.