In this literature review from 2019, the authors summarized the most recent findings on the efficacy and safety of CS in OA. Based on the results of studies presenting a low risk of bias, the most recent meta-analysis shows that only the pharmaceutical-grade CS may be considered as an appropriate background treatment for the management of knee OA.
References:
Honvo G, Bruyère O, Reginster JY. Update on the role of pharmaceutical-grade chondroitin sulfate in the symptomatic management of knee osteoarthritis. Aging Clin Exp Res. 2019;31(8):1163-1167. doi:10.1007/s40520-019-01253-z https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6661017/