Side Effects of Glucosamine Chondroitin Supplements. Do these Supplements Work?

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What is Glucosamine Chondroitin?

Glucosamine and chondroitin are two natural supplements which are taken as a treatment for osteoarthritis. Both of these are cartilaginous substances.

Glucosamine is found in healthy human cartilage, in the form of glucosamine sulfate. It is present in synovial fluid, which is present in joints, and in glycoaminoglycans, a type of molecule found in the cartilage matrix of joints.

Chondroitin is also a component of cartilage, and it helps cartilage retain moisture. Most current chondroitin supplements are derived from shark and beef cow sources.

Currently both glucosamine and chondroitin are supported by the medical industry for use as a treatment for osteoarthritis. It is believed that these two cartilage supplements can improve osteoarthritis symptoms, reduce pain, and reduce the rate of or even reverse joint degeneration.

Side Effects of Glucosamine Chondroitin

Glucosamine and chondroitin do not cause many side effects, and the supplements themselves do not cause any known serious symptoms. Possible side effects of glucosamine chondroitin supplements might include stomach upset, mild nausea, diarrhea, or heartburn.

In addition to these side effects, someone who is having an allergic reaction to chondroitin or glucosamine might have some additional symptoms. These include swelling of the throat, face, lips or tongue, difficulty breathing, or a skin rash.

Although side effects of the supplements themselves are minor, these symptoms of an allergic reaction are potentially serious. Someone who has an allergic reaction should seek emergency medical help immediately.

Is Glucosamine Chondroitin Effective?

Unfortunately, it seems that while the side effects of glucosamine chondroitin aren’t serious, the supplement isn’t really effective for the treatment of most people with osteoarthritis pain, either. Four years ago, a study published in the New England Journal of Medicine indicated that for most people, glucosamine and chondroitin didn’t reduce osteoarthritis pain by any significant level. Only a small proportion of people in the study—mostly people who had moderate to severe pain—reported that glucosamine and chondroitin helped relieve their symptoms.

In fact, the lead research on the study, a rheumatologist named Daniel Clegg, believes that when taken as supplements, chondroitin and glucosamine are broken down in the digestive system and are not incorporated into joint cartilage at all. One of the major conclusions of the clinical trial was that “Glucosamine and chondroitin sulfate alone or in combination did not reduce pain effectively in the overall group of patients with osteoarthritis of the knee.” (Clegg, et al)

Despite this new evidence about the efficacy of chondroitin and glucosamine for osteoarthritis pain, it is still a very popular supplement for people with osteoarthritis. Someone who chooses to use this supplement should consider all the information available, however, before paying more money for new doses.

This is a difficult decision to make, simply because there are no treatments for osteoarthritis that have been proven to rebuild cartilage or reverse the progression of the disease. For many people, taking glucosamine and chondroitin—even if there is doubt as to whether they work—is better than having no hope of an effective treatment. Taking these supplements might therefore contribute to mental health and wellbeing, which can in turn contribute to improved overall health.


Clegg DO, Reda DJ, Harris CL, Klein MA, O’Dell JR, Hooper MM, Bradley JD, Bingham CO 3rd, Weisman MH, Jackson CG, Lane NE, Cush JJ, Moreland LW, Schumacher HR Jr, Oddis CV, Wolfe F, Molitor JA, Yocum DE, Schnitzer TJ, Furst DE, Sawitzke AD, Shi H, Brandt KD, Moskowitz RW, Williams HJ. Glucosamine, chondroitin sulfate, and the two in combination for painful knee osteoarthritis. N Engl J Med. 2006 Feb 23;354(8):795-808.

Clinical Trials Information at the National Institute of Health: Glucosamine/Chondroitin Arthritis Intervention Trial (GAIT)

Rachel Saslow: Glucosamine and chondroitin fare poorly in pain study, but sales are strong. The Washington Post. March 16, 2010.

The Mayo Clinic: Chondroitin Sulfate

The Mayo Clinic: Glucosamine