Will Taking Chondroitin Sulfate Help Relieve Osteoarthritis Symptoms in my Knee?

What is osteoarthritis?

It is a disease affecting several different structures that make up most joints in the human body. These structures include: Articular cartilage, which is the thin rubbery film that lines the surfaces of bones when they come together to make a joint; Sub-chondral bone, which is the surface of the bones immediately below the articular cartilage, called articular cartilage; Synovial membrane, which lines the inside surface of the bag (the joint capsule) that holds the lubricating fluid in place around the joint. Physiotherapists recommend a variety of treatments, and many also recommend taking oral supplements such as chondroitin sulphate.

What is chondroitin sulfate (also spelt sulphate)?

It is a molecule much larger than glucosamine (about 16,900 Daltons), belonging to the glycosaminoglycan GAG group, and is one of several types of proteoglycans. It is composed of galactosamine and glucoronic acid. Chondroitin sulfate is a naturally occurring molecule found in various tissues. Connective tissue that contains chondroitin sulfate include that found in: papillary dermis (a thin layer just below the outer layer – epidermis – of our skin); cartilage, blood vessels, tendons and ligaments.

Does chondroitin sulfate help ease the symptoms of osteoarthritis in the knee and slow its progression?

Several studies have shown that chondroitin sulfate can mitigate the symptoms of osteoarthritis in the knee. Here are two research articles:
A study published in 2004 was carried out involving 120 people, half of whom took a placebo, and half consumed 800mg of chondroitin sulfate (containing isomer types 4 & 6 of bovine origin). Both groups took their tablets every day for two periods of three months over the course of a year. At the end of the 12 months, the group on placebo had x-ray evidence indicating joint space narrowing, whereas the group on chondroitin sulfate did not. A questionnaire was given to the participants at the beginning and at the end of the trial. It asked the people about their pain, maximum walking distance, and some activities of daily living. The group on placebo had a 23% improvement in the score of the questionnaire, whereas there was an improvement of 36% in the chondroitin sulfate group.
Another placebo controlled study was carried out in Switzerland involving 300 people with osteoarthritis. The research was published in 2005, and conducted using a randomised, double-blind protocol. Of the 300 participants, 150 took the placebo, and another 150 took 800 mg of chondroitin sulphate (containing types 4 & 6 of bovine origin), each day for two years. At the end of the two years it was found that there was no change in the average joint space of those taking chondroitin sulphate, whereas those taking the placebo did experience joint space narrowing. However, questionnaires did not reveal any significant difference between the groups in terms of pain and stiffness. It was suggested by the authors that the lack of beneficial effect in those taking the chondroitin sulphate, compared to the group taking placebo, was because both groups started off with low baseline pain scores (i.e. pain severity).
A very large study of 1583 people, published in 2006, found that chondroitin sulphate at a dose of 1200mg per day for 24 weeks resulted in a significant decrease in knee swelling,
compared to those taking a placebo. However, while the placebo caused more than 60% of those taking it only to achieve a 20% or greater decrease in pain, 65% of those taking
chondroitin sulfate had a similar response. It was concluded that therefore chondroitin sulfate was no better than placebo in terms of significantly reducing knee pain. Unfortunately the isomer type(s) of chondroitin sulphate and the animal origin(s) was not indicated in the published article.
An international study was published in 2009, involving 309 people with osteoarthritis (taking 800 mg of chondroitin sulphate), and 313 similar patients taking placebo, once a day for 2 years. This randomised, placebo controlled, double-blind study sourced patients from five different countries. The results revealed that pain relief increased faster over time in the first 9 months with those taking chondroitin sulphate compared to those taking placebo. Also, the percentage of patients with joint space narrowing greater than or equal to 0.25 mm was greater in those on the placebo (41%) compared to those on chondroitin sulphate (28%). The chondroitin sulphate was of bovine (cattle) origin, and consisted highly purified chondroitins 4 and 6 sulphate.

Why do some studies show less benefit than others?

There are several possible reasons, including some researchers using inferior forms of chondroitin sulfate (see the section headed Is all chondroitin sulfate the same?), and some using brands that have inconsistent quantities of chondroitin sulfate (see the section titled Which is the best brand of chondroitin sulfate?).

How long does it take before chondroitin sulfate creates a benefit?

Generally about 3 to 6 months of continuous treatment.

How might chondroitin sulfate help articular cartilage affected by osteoarthritis?

Chondroitin sulfates are naturally produced by chondrocytes and bone cells. Chondroitin sulfate help produce molecules called proteoglycans from chondrocytes, reduces the production of matrix metalloproteinases, has an anti-inflammatory effect, and interferes with the programmed cell death (apoptosis) of chondrocytes. They also impair the production of cytokines by cartilage cells, which may mean less stimulation of nerve cells signalling pain.

Do any official medical societies recommend the use of chondroitin sulphate?

A treatment approach for knee OA published in 2014 by the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis (ESCEO) recommends the initiation of ‘background therapy with chronic symptomatic slow-acting drugs for osteoarthritis (SYSADOAs), with the addition of paracetamol as short-term rescue analgesia as needed … Among SYSADOAs, the evidence is greatest for the effect of prescription-grade glucosamine sulfate (GS) and chondroitin 4 & 6 sulfate (CS).’

Why doesn't chondroitin sulfate help all people with osteoarthritis?

Part of the answer may be that not all individuals have the same gut bacterial populations, and that these differing populations degrade CS to varying extents. Is it preferable to have chondroitin sulfate injected? Given that CS can be degraded to some extent by gut bacteria, it would seem to be logical to consider injections. It seems that injections of chondroitin sulfate as the sole active ingredient into the knees of individuals with OA has not been well researched. However, injections of CS in combination with hyaluronic acid have been shown to help a large percentage of the 112 patients that received the three weekly injections.

Is all chondroitin sulfate the same?

No. One study examined the effect of three different chondroitin sulfate compounds, one sourced from pigs and two from cattle, but all from different manufacturers. Their research showed that not all chondroitin sulfate acted similarly, and one even increased the amount of damaging constituents while decreasing the factors which promoted articular cartilage health. This may be one of the reasons why some studies show a greater benefit on people with osteoarthritis than other studies.

Which is the best brand of chondroitin sulphate?

The following information is sourced from a study published in The Journal of the American Nutraceutical Association, 2000. The researchers examined 11 products from the marketplace that contain chondroitin sulfate (some of which also contained glucosamine hydrochloride or glucosamine sulfate). Once again it was discovered that the amount found after analysis was significantly different from the label in many of these commercial products, with deviations from label claims ranging from as low as 33% to 110%. So if you bought a brand that claimed that the capsules contained 1000mg of chondroitin, the tablets may in fact only have a third of that amount. The authors indicated that part of the lack of uniform quantity may have been because there was no legal requirement in the USA for the manufacturers of glucosamine and chondroitin to use ‘pharmaceutical Good Manufacturing Practices to guarantee high quality, batch-to-batch consistency.’

The only Australian commercially available chondroitin sulfate that I could find at a reasonable price for delivering 800 mg of the correct type of chondroitin per day are BioOrganics Glucosamine 750 mg Chondroitin 400 mg and Nature’s Own Glucosamine Sulfate & Chondroitin >> Advanced with bovine sodium chondroitin sulfate 400mg per tablet. This product is widely available in Australia. A business variously called Chondrosulf Australia or CS Ethical Pty Ltd advertise that they distribute Chondrosulf in Australia, however this appears to be a scam. The Office of Fair Trading has been notified.


I suggest that patients do their own research on their bodies by working in conjunction with a physiotherapist. At IceFire Physiotherapy, the general plan would be to: Step 1. Have an
examination and complete a questionnaire before taking chondroitin sulfate; Step 2. Take at least 800mg of chondroitin 4 & 6 sulfate daily for 6 months, and then complete the questionnaire again and have another physiotherapy examination; Step 3. Cease taking it for another 6 months and repeat the examination and questionnaire.

However, as chondroitin sulfate is usually available in combination with other potentially beneficial substances, such as glucosamine, then stay tuned for the next two blog posts which will look at glucosamine supplementation on its own, and what might happen if you take them in combination.

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