Glucosaminsulfate and Chondroitin sulfate for joints


Many older swimmers are probably already taking either glucosamine sulfate or chondroitin sulfate or both.


What is glucosamine sulfate?

Glucosamine sulfate is a basic building block used by the body to make cartilage, as well as tendons, ligaments, skin, heart valves, bone, and synovial fluid (joint fluid). It is also one of the molecules used by the body to synthesize chondroitin sulfate. Most of the research has focused on glucosamine sulfate and joints.


Joints are the intersection of two bones whose ends are covered in cartilage. The joint capsule surrounds the two bony ends and has an inner synovial lining that secretes synovial fluid to protect and lubricate the cartilage ends. Ligaments provide stability by connecting bone to bone and lie outside the joint capsule. Tendons connect muscle to bone.


What is chondroitin sulfate?


Chondroitin sulfate is a larger molecule used by the body to make cartilage, ligaments, tendons, and bone. Glucosamine is one of its building blocks. Like glucosamine, chondroitin sulfate has been studied mainly in its role with joints.


What is arthritis?


Arthritis is generally an acute inflammation of a joint. The most common form of arthritis is osteoarthritis, or degenerative joint disease (DJD). This is the arthritis of aging and its symptoms are felt in the joints. By age forty, 90% of the population will have some degree of degenerative joint disease, including decreased joint space and bone spurs (osteophytes), but not everyone will have symptoms.  A feeling of stiffness in the joints in the morning is a typical sign of arthritis.   Knees, hips, hands, fingers, lower back, and neck are the joints most commonly affected.


 How do glucosamine sulfate and chondroitin sulfate work?


Radiographs of joints affected by DJD show joint space narrowing. In reality, this is a decrease in the thickness of the cartilage around the ends of the bones. Cartilage is made by cells called chondrocytes. As we age, the chondrocytes produce less cartilage. Glucosamine sulfate increases production of cartilage in two ways.  First, the chondrocytes use it directly as raw material to make more cartilage.  Secondly, glucosamine sulfate stimulates the chondrocytes to manufacture more cartilage and to replace unhealthy cartilage with fresh, healthy cartilage. Healthy cartilage, in turn, allows more good nutrients to reach the chondrocytes, and thus continue the cycle of creating more healthy cartilage.  Glucosamine sulfate also inhibits the breakdown of cartilage.


While less research has been done on chondroitin sulfate, it too appears to help the joints, by increasing the viscosity and amount of joint fluid (hyaluronic acid), inhibiting the breakdown of cartilage, and reducing joint inflammation.


How does glucosamine sulfate compare to non-steroidal anti-inflammatory drugs?


Studies have shown that patients who take non-steroidal anti-inflammatory drugs (NSAIDs) felt better initially, but after three to six weeks, the group on glucosamine sulfate felt better. While they reduce pain and inflammation, NSAIDs inhibit the production of new cartilage. This prevents the joints from healing and improving.  When NSAIDs and glucosamine sulfate are taken together, joints did not deteriorate as rapidly as when only NSAIDs are taken.


What kind of supplements are most effective?


Both glucosamine sulfate and glucosamine hydrochloride supplements are sold.  Although the manufacturers of glucosamine hydrochloride say that there is no difference between the two, all the studies showing positive effects were with glucosamine sulfate, and no studies to date have shown that the hydrochloride works. For that reason, if you are purchasing glucosamine, make sure it is glucosamine sulfate and not glucosamine hydrochloride. 90% of glucosamine sulfate is absorbed.


Purified chondroitin sulfate is absorbed by the human gastrointestinal tract, but probably not nearly as well as glucosamine sulfate. Purified chondroitin sulfate is very expensive., which tests natural food store supplements, found that most supplements labeled glucosamine do contain glucosamine. However, supplements containing a combination of glucosamine and chondroitin generally do not contain chondroitin in amounts considered effective.  Generally supplements available to professionals, such as chiropractors and naturopathic doctors, are more consistently of higher quality. If you buy your supplements from a health food store, check the website first for the most effective products. 


What about dosing, side effects, and contraindications?


The average dose for glucosamine sulfate is 1500 mg per day and for chondroitin sulfate 1200 mg.  It can be taken in one dose, or split into several doses.  Side effects for both supplements are minimal, particularly when compared to NSAIDs, and consist primarily of digestive complaints. People who are highly sensitive to shellfish might want to avoid glucosamine sulfate, since it is manufactured from shellfish, but no known adverse cases have been reported.  Diabetics should discuss glucosamine with their doctors before taking it, and should be careful to monitor their blood sugar initially.  As with any supplement, stop taking it if it makes you feel bad.


Some final thoughts


While most of the research on glucosamine sulfate has been done on DJD, I have found that it helps in healing swimming and other sports related injuries. This makes sense, as it is a building block for tendons and ligaments.  It is particularly helpful in cases of knee injuries because of its healing effect on the knee cartilage and the cartilaginous menisci of the knee. For acute injuries, I would recommend 1500 mg per day until the injury has healed.


Dr. Jessica Seaton is a chiropractic orthopedist in private practice in West Los Angeles. She is the current chair of the USMS Sports Medicine Committee. She has been swimming with West Hollywood Aquatics for over 12 years. She may be reached at (310) 470-0282 or