Chondroitin sulfate (CS) is one of two products purchased over-the-counter by many people with osteoarthritis (OA). The other supplement is called glucosamine. These nutraceuticals have been used alone or combined together by many arthritis sufferers.
Research and regulation of these products began in Europe over 20 years ago. The United States has been much slower to follow in its use of these supplements. There have been enough studies now to recognize some patterns with CS use.
For example, it appears that there's a placebo response in the first few weeks using these products. That means people feel better because they think the pill is working. In the case of CS, its analgesic (pain relieving) effects are slow to kick in. It takes two to three months before getting maximal pain relief from this product.
There's some evidence that CS works better when it's combined with glucosamine. And these products seem to have their best effect in patients who have moderate to severe OA pain.
Patients with early stage OA may not see the benefit in pain relief or improved function. It's possible these nutraceuticals help slow or even stop the progression of OA. This hasn't been proven yet. If it's true, then taking CS and/or glucosamine at the first sign of OA might be recommended.