Do Your Knees Really Love Glucosamine and Chondroitin Supplements?

According to one estimate, about 20% of adults in the US take glucosamine and about 10% take chondroitin. The cost of these and other non-vitamin supplements and herbal remedies is close to 15 billion dollars every year. These are popular supplements.

• Glucosamine serves as a building block for proteins in hyaline cartilage, so supplementation is therefore believed to improve joint function and reduce pain. Previous research has been conducted with mixed results, making the true benefits unclear. Studies following sport-related injuries showed no benefits related to recovery or pain.
• Chondroitin is found in the hyaline cartilage of synovial joints and is therefore also believed to improve joint function over time. The majority of previous research on chondroitin has focused on elderly populations; long-term supplementation (>1 year) has been shown to create structural changes in joints, but many other studies show no benefits.

The two compounds are generally used for osteoarthritis relief and prevent joint disease - even though the research presents very mixed conclusions. A recent 2010 meta-analysis found that among >3,800 people with osteoarthritis of the knee or hip, treatment with glucosamine, chondroitin or a combination of the two was no better than placebo. Of greater interest, a 2016 study including 164 patients with knee pain due to osteoarthritis demonstrated users reporting worse symptoms than those taking a placebo – as well as side effects such as diarrhea and abdominal pain.

Does this indicate an end to glucosamine and chondroitin supplementation? Not likely. The fact stands that many people seem to perceive real relief from the compounds – even if it is just a placebo effect. Placebo or not the benefits for some appear real, and a single study is not likely to change their mind. In general, glucosamine and chondroitin are thought to be safe. Anecdotal side effects generally include heartburn, drowsiness, headaches, or allergic reactions (more common among those allergic to shellfish). Chondroitin may act as a blood thinner, so it comes with a warning about potential bleeding. Drug interactions should always be considered, so users should check with their doctor or pharmacist before taking either supplement.

For advocates of glucosamine and/or chondroitin, this recent study is another bit or negative news to mix in with various conflicting findings over the years. Consumers should understand that there are various types and doses available, and they are taken for a number of different conditions. Additional research is clearly needed to get conclusive results for best recommendations by fitness professionals.