Chondroitin generally does not cause much in the way of side effects, besides occasional mild digestive distress.
However, there is one case report of an exacerbation of asthma caused by use of a glucosamine-chondroitin product.210
In addition, there are theoretical concerns that chondroitin might have a mild blood-thinning effect, based on its chemical similarity to the anticoagulant drug heparin. Reassuringly, 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 who are temporarily at risk for bleeding (for example, 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), or pentoxifylline (Trental), do not use chondroitin except under physician supervision.
Scientists are unsure how chondroitin sulfate works (if indeed it does).But, 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.45,208 Another theory holds that chondroitin increases the amount of hyaluronic acid in the joints.209 Hyaluronic acid is a protective fluid that keeps the joints lubricated. Finally, chondroitin may have a mild anti-inflammatory effect.208
As described in the previous section, the supplement chondroitin is often combined with glucosamine. Several studies have evaluated chondroitin used alone, as well, with some positive results, both for improving symptoms and slowing the progression of the disease. On balance, however, the evidence for chondroitin’s effectiveness for osteoroarthritis remains inconsistent.197
Chondroitin is not an essential nutrient, meaning it is not made in our bodies, and must be obtained through diet. Animal cartilage is the only dietary source of chondroitin. (When it's on your plate, animal cartilage is called gristle.) If you chew gristle, you may be able to obtain chondroitin naturally. Otherwise, you'd con obtain chondroitin in pill form from a health food store or pharmacy.
The usual dosage of chondroitin is 400 mg taken 3 times daily, indefinitely. Two studies used an "on and off" schedule of chondroitin (taking it for 3 months, going off of it for 3 months, and then taking it again).121 Other studies involved taking chondroitin daily. Regardless of which way you use it, be patient! The results are thought to take weeks to develop.
In commercial products, chondroitin is often combined with glucosamine. Preliminary information from one animal study suggests that this combination may be superior to either treatment alone.204,205
Not all supplements are created equally! There are large differences between chondroitin products based on their chemical structure.206 This can be expected to lead to significant differences in absorption and hence effectiveness. Most likely, chondroitin products with physically smaller molecules (fewer than 16,900 daltons) are better absorbed. In addition, a review conducted in 2003 by the respected testing organization, Consumerlab.com, found that some products sold as providing chondroitin actually contained far less chondroitin (or even none at all) than stated on the label.207 It may be advisable to use the exact products that were tested in double-blind trials.
Chondroitin is not an essential nutrient, meaning it is not made in our bodies, and must be obtained through diet. Animal cartilage is the only dietary source of chondroitin. (When it's on your plate, animal cartilage is called gristle.) If you chew gristle, you may be able to obtain chondroitin naturally. Otherwise, you'd con obtain chondroitin in pill form from a health food store or pharmacy.
The usual dosage of chondroitin is 400 mg taken 3 times daily, indefinitely. Two studies used an "on and off" schedule of chondroitin (taking it for 3 months, going off of it for 3 months, and then taking it again).121 Other studies involved taking chondroitin daily. Regardless of which way you use it, be patient! The results are thought to take weeks to develop.
In commercial products, chondroitin is often combined with glucosamine. Preliminary information from one animal study suggests that this combination may be superior to either treatment alone.204,205
Not all supplements are created equally! There are large differences between chondroitin products based on their chemical structure.206 This can be expected to lead to significant differences in absorption and hence effectiveness. Most likely, chondroitin products with physically smaller molecules (fewer than 16,900 daltons) are better absorbed. In addition, a review conducted in 2003 by the respected testing organization, Consumerlab.com, found that some products sold as providing chondroitin actually contained far less chondroitin (or even none at all) than stated on the label.207 It may be advisable to use the exact products that were tested in double-blind trials.
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 as a treatment for osteoarthritis, the typical arthritis that many people suffer as they get older. However, the supporting evidence for this use is weak.
Symptom Relief
According to some but not all double-blind, placebo-controlled studies chondroitin may relieve symptoms of osteoarthritis.
One study enrolled 85 people with osteoarthritis of the knee and followed them for 6 months.34 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.
Good results were seen in a 12-month, double-blind trial that compared chondroitin against placebo in 104 individuals with arthritis of the knee,35 as well as in a 12-month trial of 42 participants.36
Another interesting study evaluated intermittent or “on and off” use of chondroitin.121 In this study, 120 people received either placebo or 800 mg of chondroitin sulfate daily for two separate 3-month periods over a year. The results showed that even when taken this way, use of chondroitin improved symptoms.
Benefits were also seen in two short-term trials involving a total of about 240 individuals.37,38
Generally positive results were also seen in other studies, including one that found chondroitin about as effective as the anti-inflammatory drug diclofenac.40-42
However, a very large (1,583-participants) and well-designed study failed to find either chondroitin or glucosamine plus chondroitin more effective than placebo.153 When this study is pooled together with the two other best designed trials, no overall benefit is seen.185 Yet another study also failed to find benefit with glucosamine plus chondroitin.187 It has been suggested that chondroitin, like glucosamine, may primarily show benefit in studies funded by manufacturers of chondroitin products.
Research Evidence for how Chondroitin Slows the Progression of Osteoarthritis
Some evidence suggests that, like glucosamine, chondroitin might slow the progression of arthritis.
An important feature of the study of 42 individuals mentioned previously was that the individuals taking a placebo showed progressive joint damage over the year, but among those taking chondroitin sulfate no worsening of the joints was seen.43 In other words, chondroitin sulfate seemed to protect the joints of osteoarthritis sufferers from further damage.
A longer and larger double-blind, placebo-controlled trial also found evidence that chondroitin sulfate can slow the progression of osteoarthritis.44 One hundred and nineteen people were enrolled in this study, which lasted a full 3 years. Thirty-four of the participants received 1,200 mg of chondroitin sulfate per day; the rest received placebo. Over the course of the study researchers took x-rays to determine how many joints had progressed to a severe stage.
During the 3 years of the study, only 8.8% of those who took chondroitin sulfate developed severely damaged joints, whereas almost 30% of those who took placebo progressed to this extent.
Similar long-term benefits were seen in two other studies, enrolling a total of more than 200 people.45,122
Additional evidence comes from animal studies. Researchers measured the effects of chondroitin sulfate (administered both orally and via injection directly into the muscle) in rabbits, in which cartilage damage had been induced in one knee by the injection of an enzyme.46 After 84 days of treatment, the damaged knees in the animals that had been given chondroitin sulfate had significantly more cartilage left than the knees of the untreated animals. Taking chondroitin sulfate by mouth was as effective as taking it through an injection.
Looking at the sum of the evidence, it does appear that chondroitin sulfate may actually protect joints from damage in osteoarthritis. However, the scientific record suffers from a paucity of truly independent researchers.
Scientists are unsure how chondroitin sulfate works (if indeed it does).But, 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.45,208 Another theory holds that chondroitin increases the amount of hyaluronic acid in the joints.209 Hyaluronic acid is a protective fluid that keeps the joints lubricated. Finally, chondroitin may have a mild anti-inflammatory effect.208
As described in the previous section, the supplement chondroitin is often combined with glucosamine. Several studies have evaluated chondroitin used alone, as well, with some positive results, both for improving symptoms and slowing the progression of the disease. On balance, however, the evidence for chondroitin’s effectiveness for osteoroarthritis remains inconsistent.197
