Glucosamine

NATURAL PRODUCTS

Glucosamine and Chondroitin

Glucosamine and chondroitin do not fall under herbal products, but they are included here because of their popularity and to demystify them. Glucosamine and chondroitin have found a niche in helping people with osteoarthritis by lessening the symptoms of the disease. They are not replacements for standard medical and pharmacological treatment for osteoarthritis, but they can be used to supplement these therapies. Glucosamine and chondroitin have not been appropriately studied for rheumatoid arthritis and apparently have no place in the management of this autoimmune disease that affects multiple joints and organs.

Several studies have been done regarding the efficacy of glucosamine and chondroitin, but there are none of sufficient duration and control to conclude that glucosamine or chondroitin are effective in treating osteoarthritis long term. These studies have reported that glucosamine and chondroitin are quite variable in their effects on pain reduction and improvement of joint functionality. Even though the effects were variable, there was a consistent theme among the studies that glucosamine and chondroitin therapy apparently had some degree of efficacy. Further controlled studies free of bias are required to ascertain whether glucosamine and chondroitin actually are efficacious in the long term therapy of osteoarthritis. However, people that take either component claim they are helped by the product.

One significant problem with the studies on the efficacy of glucosamine and chondroitin is that many have not been performed in a manner that would disprove their effectiveness. For example, a study done in China and reported in 1998, compared the efficacy of glucosamine 1,500 mg/day alone against ibuprofen (Motrin) 1,200 mg/day on osteoarthritis of the knee, for a period of four weeks, in 178 Chinese patients. The authors concluded that glucosamine was better tolerated and was effective in decreasing the symptoms of osteoarthritis. They also claimed that glucosamine was slightly more effective that ibuprofen. The study neglected to address the relatively low dose of ibuprofen (1,200 mg/day), which if increased would have increased its efficacy. It also failed to study the effects of other nonsteroidal antiinflammatory drugs, such as naproxen (Naprosyn) or indomethacin (Indocin), since there is considerable variability in how patients respond to different NSAID drugs. Unfortunately, this study was unable to address a comparison of glucosamine to the new COX-2 cyclooxygenase inhibitors, like Vioxx and Celebrex, which are better tolerated than the COX-1 inhibitors, like ibuprofen. Moreover, the study was limited to four weeks, which may not have been sufficient time for ibuprofen to have an antiinflammatory effect on the joints. It takes approximately one to two weeks for the antiinflammatory effect of continuous ibuprofen dosing to kick in for osteoarthritis. The analgesic effect occurs in a few hours. Additionally, it is important to note that NSAID drugs do not reverse the degeneration of the joints in osteoarthritis. They only treat the symptoms.

Another 1999 published study performed by the U.S. Navy compared the effectiveness of glucosamine 1,500 mg/day with chondroitin 1,200 mg/day versus placebo in a double-blind crossover study consisting of 34 males with degenerative joint disease of the knee or lower back. The results of the study indicated an improvement in functionality and a decrease in pain for degenerative joint disease of the knee, but concluded nothing about the lower back. The authors concluded that glucosamine and chondroitin relieved symptoms of osteoarthritis. Unfortunately, the sample size was too small to ascertain whether the reported improvement was actually clinically significant and whether it could be repeated with similar improvement over several hundred people with similar disease.

Glucosamine and chondroitin tend to be marketed as a combination product containing the two, but there is no information showing that the two ingredients must be administered together. In fact, some literature reviews have reported that glucosamine alone is equally effective to the combination product. It is believed that glucosamine acts as a biochemical substrate in the formation of proteoglycans in the cartilage joint matrix. Chondroitin acts in a different fashion but also is involved in the formation of compounds in the cartilage joint matrix. Additional studies are required to address whether glucosamine and chondroitin actually help reverse the course of joint degeneration in osteoarthritis.

The generally accepted dose or serving size of glucosamine is 1,500 mg/day and that of chondroitin is 1,200 mg/day based on an average person weighing about 154 pounds (70 kg). Manufacturers offer a combination of these two products in this fixed ratio, but in order to reach the effective dose, multiple capsules or tablets must be taken daily. The daily dose is normally divided equally and taken three times a day with meals. As with the herbal medications, quality is an issue, as some products have questionable quality assurance and some reportedly contained none of the labeled product.

The daily dose or serving may be adjusted depending on the person’s weight in relation to the 154 pound average, but there is no solid evidence that such an adjustment is necessary. Neither is there any solid evidence that such an adjustment will not change the efficacy of the treatment. Furthermore, there is no evidence showing whether the daily dose of an obese person should be adjusted based on lean body weight, total body weight, or a weight somewhere in the middle between the two. Based on this information, a person weighing 120 pounds, for example, could calculate their dose to be approxmately 80% of the dose for a person weighing 150 pounds, based on the glucosamine or chondroitin amounts. In this case, the daily dose would be glucosamine 1,200 mg (80% of 1,500 mg) and chondroitin 960 mg (80% of 1,200 mg). If such a dose is not possible, because of the amounts of product present in each capsule or tablet, take the next lower dose that can be attained.

Although controlled studies have yet to show that glucosamine and chondroitin reverse the course of osteoarthritis, there has been discussion that there may be some improvement due to these products. Adding glucosamine and chondroitin to a current medical treatment of osteoarthritis that includes prescription NSAIDs may be beneficial and may enhance the efficacy of the NSAID alone. Further properly conducted controlled studies with positive outcomes will be required before such a combination could be deemed acceptable therapy for osteoarthritis.

Some products add methylsulfonymethane (MSM) to glucosamine and chondroitin. but there is no proven benefit provided by MSM. MSM is related to DMSO (dimethylsulfoxide). MSM is touted as a source of organic sulfur, which may be true, but most people are not sulfur deficient, because sulfur is found in the normal diet. It is best to avoid products containing methylsulfonylmethane. MSM should not be taken internally or applied externally by people with a known or suspected allergy to sulfur.

Side effects to the administration of glucosamine and chondroitin are mild and include drowsiness, headache, gastrointestinal problems, and skin reactions. Based on these side effects, it may be advisable to take the product with food and to use caution while driving or working with machinery. There are no known drug interactions with glucosamine or chondroitin. However, glucosamine does contain glucose and there are some studies showing it can cause insulin resistance. Therefore, it should be avoided by many diabetics or blood sugars should be closely monitored under the supervision of a physician or pharmacist.

Since chondroitin is derived from shark, people with an allergy to shark or fish should exercise caution or avoid products containing chondroitin. Such people should consider products containing glucosamine alone. As with other natural products, the physician who is treating the disease should be consulted, prior to starting the glucosamine and chondroitin combination products or either component alone. In addition, it is desirable to discuss these products with a pharmacist for additional information, product selection, dosing, side effects, and safety issues.

Legal Info: Solumedia is not responsible for errors or omissions. The information provided on the natural product pages is only a guideline based on current literature and the pharmacological action of these products. It should not be used as the sole source of information on these products. Many of the drug interactions listed are not found in current literature but are based on likely interactions due to the actions of the interacting drugs. It is recommended that a qualified and licensed healthcare professional be consulted for additional information. Although the information provided is from reliable sources, Solumedia has no liability. This information is provided only as a service.

This page was last updated on 04/29/05.