Chondroitin sulfate is a naturally occurring glycosaminoglycan found in cartilage and is commonly used as a dietary supplement aimed at supporting joint health and treating cartilage damage, especially in osteoarthritis (OA). The rationale for its use is based on its role in cartilage structure and purported ability to aid in cartilage repair and reduce degradation.

Scientific evidence for chondroitin sulfate's effectiveness is mixed. Several randomized controlled trials and meta-analyses have evaluated its efficacy in reducing pain and improving function in individuals with OA. Some studies have found modest benefits, particularly in pain reduction and improved joint function, compared to placebo. For example, a 2011 Cochrane review concluded that chondroitin sulfate may reduce pain slightly more than placebo and improve physical function, but the effect size was small and of questionable clinical relevance. Notably, some large, well-conducted studies (e.g., the GAIT trial) have found no significant difference between chondroitin and placebo.

Overall, the use of chondroitin sulfate in the management of cartilage damage is supported by a moderate level of scientific evidence, with benefits generally being small to moderate and not consistently observed across all studies. Major clinical guidelines vary in their recommendations, with some supporting its use as an option for symptom management and others advising against it due to inconsistent findings. No major safety concerns have been identified with its use.