Herbs & Supplements:
Chondroitin
Supplement Forms / Alternate Names
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Chondroitin Sulfate
Principal Proposed Uses
•
Osteoarthritis
Other Proposed Uses
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Atherosclerosis, High Cholesterol
Chondroitin sulfate is a naturally occurring substance in the body. It is a major constituent of cartilage—the tough, elastic connective tissue found in the joints.
Based on the evidence of preliminary double-blind studies, chondroitin is widely used in Europe as a treatment for osteoarthritis, the "wear and tear" arthritis that many people suffer as they get older.
Furthermore, chondroitin may go beyond treating symptoms and actually protect joints from damage. Current medical treatments for osteoarthritis, such as NSAIDs (nonsteroidal anti-inflammatory drugs), treat the symptoms but don't actually slow the disease's progression, and they may actually make it get worse faster.1–5 Chondroitin (along with glucosamine and SAMe) may take the treatment of osteoarthritis to a new level. However, more research needs to be performed to prove definitively that this exciting possibility is real.
Sources
Chondroitin is not an essential nutrient. Animal cartilage is the only dietary source of chondroitin. (When it's on your plate, animal cartilage is called gristle.) Unless you enjoy chewing gristle, you'd do best to obtain chondroitin in pill form from a health food store or pharmacy.
Therapeutic Dosages
The usual dosage of chondroitin is 400 mg taken 3 times daily. Be patient! The results take weeks to develop. In commercial products it is often combined with glucosamine. Preliminary information from one animal study suggests that this combination may be superior to either treatment alone.6,7
There are large differences between chondroitin products based on their chemical structure.8 This can be expected to lead to significant differences in absorption and hence effectiveness. Most likely, chondroitin products with physically smaller molecules (less than 16,900 daltons) are better absorbed. It may be advisable to use the exact products that were tested in double-blind trials.
Therapeutic Uses
Initially, chondroitin was primarily used in an injectable form. But in recent years, double-blind studies using the oral form of chondroitin for osteoarthritis have been reported.9,10,11 The best evidence is for a pain-relieving effect, but some studies have found that it can also slow the progression of the disease.12–15
Chondroitin has also been proposed as a treatment for other conditions such as atherosclerosis and high cholesterol, but as yet the evidence that it might help is quite preliminary.16,17
What Is the Scientific Evidence for Chondroitin?
For years, experts stated that oral chondroitin couldn't possibly work, because its molecules are so big that it seemed doubtful that they could be absorbed through the digestive tract. However, in 1995 researchers laid this objection to rest when they found evidence that up to 15% of chondroitin is absorbed intact.18
Reducing Symptoms of Osteoarthritis
Double-blind placebo-controlled studies involving a total of several hundred participants suggest that chondroitin can relieve symptoms of osteoarthritis. One study enrolled 85 people with osteoarthritis of the knee and followed them for 6 months.19 Participants received either 400 mg of chondroitin sulfate twice daily or placebo. At the end of the trial, doctors rated the improvement as good or very good in 69% of those taking chondroitin sulfate but in only 32% of those taking placebo.
Another way of comparing the results is to look at maximum walking speed among participants. Whereas individuals in the chondroitin group were able to improve their walking speed gradually over the course of the trial, walking speed did not improve at all in the placebo group. Additionally, there were improvements in other measures of osteoarthritis, such as pain level, with benefits seen as early as 1 month. This suggests that chondroitin was able to stop the arthritis from gradually getting worse (see also Slowing the Progression of Osteoarthritis).
Good results were seen in a 12-month double-blind trial that compared chondroitin against placebo in 104 individuals with arthritis of the knee,20 as well as in a 12-month trial of 42 participants.21
Benefits were also seen in two short-term trials involving a total of about 240 individuals.22,23
In addition, a 6-month double-blind placebo-controlled study of combined glucosamine, chondroitin, and manganese found evidence of significant improvement in the treated group.24
Generally positive results were also seen in other studies, including one that found chondroitin about as effective as theanti-inflammatory drug dicoflenac.25,26,27
Slowing the Progression of Osteoarthritis
An interesting feature of the study of 42 individuals mentioned previously was that, whereas the placebo group showed progressive joint damage over the year, no worsening of the joints was seen in the group taking chondroitin.28 In other words, chondroitin seemed to protect the joints from damage, thus slowing or perhaps even halting the progression of the disease.Osteoarthritis tends to get worse with time.
As mentioned earlier, no conventional treatment for osteoarthritis protects joints from progressive damage, and some may actually accelerate the process. If further studies confirm that chondroitin prevents progressive damage to the joints, it would make chondroitin distinctly better than any conventional option. Unfortunately, this study was too small to prove anything on its own.
Another, larger study examined the progression of osteoarthritis in 119 people for 3 full years.29 In this double-blind placebo-controlled trial, those who took 1,200 mg of chondroitin daily showed lower rates of severe joint damage. Only 8.8% of the chondroitin group developed severely damaged joints during the 3 years of the study, compared with almost 30% of the placebo group. This suggests that chondroitin was slowing the progression of osteoarthritis. Unfortunately, the researchers did not report whether this difference was statistically significant.
Slowing of disease progression was also seen in the 1-year study of 104 individuals described previously.30
Additional evidence comes from animal studies. The effect of both oral and injected chondroitin was assessed in rabbits with damaged cartilage in the knee.31 After 84 days of treatment, the rabbits that were given chondroitin had significantly more healthy cartilage remaining in the damaged knee than the untreated animals. Receiving chondroitin by mouth was as effective as taking it through an injection.
Putting all this information together, it appears quite likely that chondroitin can slow the progression of osteoarthritis. However, more studies are needed to confirm this very exciting possibility. It would also be wonderful if chondroitin could repair damaged cartilage and thus reverse arthritis, but none of the research so far shows such an effect. Chondroitin may simply stop further destruction from occurring.
How Does Chondroitin Work for Osteoarthritis?
Scientists are unsure how chondroitin sulfate works, but one of several theories (or all of them) might explain its mode of action.
At its most basic level, chondroitin may help cartilage by providing it with the building blocks it needs to repair itself. Chondroitin is also believed to block enzymes that break down cartilage in the joints.32,33 Another theory holds that chondroitin increases the amount of hyaluronic acid in the joints.34 Hyaluronic acid is a protective fluid that keeps the joints lubricated. Finally, chondroitin may have a mild anti-inflammatory effect.35
Safety Issues
Chondroitin sulfate has not been associated with any serious side effects, which is not surprising when you consider that taking it by mouth is essentially the same as eating gristle. Subjects in clinical trials have found mild digestive distress to be the only real complaint.
Based on chondroitin’s chemical similarity to the anticoagulant drug heparin, it has been suggested that chondroitin might have “blood-thinning” effects as well. There are no case reports of any problems relating to this, and studies suggest that chondroitin has, at most, a mild anticoagulant effect.36 Nonetheless, prudence suggests that, based on these findings, chondroitin should not be combined with blood-thinning drugs, such as warfarin (Coumadin), heparin, and aspirin, except under physician supervision. In addition, individuals with bleeding problems, such as hemophilia, or temporarily at risk for bleeding (e.g., undergoing surgery or labor and delivery) should avoid chondroitin.
Interactions You Should Know About
If you are using drugs that impair blood coagulation, such as warfarin (Coumadin), heparin, aspirin, clopidogrel (Plavix ), ticlopidine (Ticlid), and pentoxifylline (Trental), do not use chondroitin except under physician supervision.
View References
Last reviewed August 2002 by Medical Review Board
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