Diet & Fitness

Chondroitin sulfate (CS) is a major component of the lining of joints. The structure of CS includes molecules related to glucosamine sulfate. CS levels have been reported to be reduced in joint cartilage affected by osteoarthritis. Possibly as a result, CS supplementation may help restore joint function in people with osteoarthritis.³ On the basis of preliminary evidence, researchers had believed that oral CS was not absorbed in humans;⁴ as a result, early double-blind CS research was done mostly by giving injections.^3,6 This research documented clinical benefits from CS injections. It now appears, however, that a significant amount of CS is absorbable in humans,⁷ though dissolving CS in water leads to better absorption than swallowing whole pills.⁸

Strong clinical evidence now supports the use of oral CS supplements for osteoarthritis. Many double-blind trials have shown that CS supplementation consistently reduces pain, increases joint mobility, and/or shows evidence (including X-ray changes) of healing within joints of people with osteoarthritis.^{9,10,11,12,13,14,15,16,17,18,19} Most trials have used 400 mg of CS taken two to three times per day. One trial found that taking the full daily amount (1,200 mg) at one time was as effective as taking 400 mg three times per day.¹² Reduction in symptoms typically occurs within several months.

Chondroitin sulfate is a large structural polysaccharide found in connective tissues including in blood vessel walls, where it appears to form complexes with cholesterol that contribute to atherosclerosis.¹⁹ Clinical trials performed in the 1960s and 1970s reported supplemental chondroitin sulfate had cholesterol-lowering effects and could slow atherosclerosis progression.²⁰ For example, in one controlled trial that included 48 elderly participants with atherosclerosis, those given 4.5 grams of chondroitin sulfate daily had lower cholesterol levels, slower clotting times, and a lower mortality rate after 64 months.²¹ Another trial found chondroitin sulfate reduced the risk of coronary events (heart attack or serious episode of low blood flow to the heart) seven-fold during six years of monitoring.²² More recently, a trial in 48 subjects with obesity and knee osteoarthritis found eight weeks of supplementation with 600 mg of chondroitin sulfate daily not only reduced knee pain and dysfunction but also lowered total cholesterol levels and improved markers of inflammation and glucose metabolism relative to placebo.²³ Some evidence suggests chondroitin sulfate interacts with LDL-cholesterol, reduces cholesterol accumulation in vessel walls, and decreases lipoprotein oxidation.^24,25,26

 

Preliminary research shows that chondroitin sulfate may prevent atherosclerosis in animals and humans and may also prevent heart attacks in people who already have atherosclerosis.^27,28 However, further research is needed to determine the value of chondroitin sulfate supplements for preventing or treating atherosclerosis.

Years ago, researchers reported that taking for six years substantially reduced the risk of fatal and nonfatal heart attacks in people with . Chondroitin may work by inhibiting and by acting as an anticoagulant. The few doctors aware of these older studies sometimes recommend that people with a history of heart disease or who are at risk for heart attack take approximately 500 mg of chondroitin sulfate three times per day.

 

Glucosamine sulfate and chondroitin sulfate may both play a role in wound healing by providing the raw material needed by the body to manufacture molecules called glycosaminoglycans found in skin, tendons, ligaments, and joints.²⁹ Test tube and animal studies have found that these substances, and others like them, can promote improved tissue healing.^30,31,32,33 Injectable forms of chondroitin sulfate have been used in Europe for various types of sports-related injuries to tendons and joints,^34,35,36,37 and one preliminary trial reported reduced pain and good healing in young athletes with chondromalacia patella (cartilage softening in the knee) who were given 750–1,500 mg per day of oral glucosamine sulfate.³⁸ However, specific human trials of glucosamine and chondroitin sulfate for healing sprains and strains are lacking.

 

Chondroitin sulfate may play a role in reducing the risk of kidney stone formation. One trial found 60 mg per day of glycosamionoglycans significantly lowered urinary oxalate levels in stone formers.³⁹ Chondroitin sulfate is a type of glycosaminoglycan. A decrease in urinary oxalate levels should reduce the risk of stone formation.