No, not all available products are the same. Chondroitin may come from bovine (cow), porcine (pig), or marine sources, or can be made through a process of bacterial fermentation (and therefore can be free from animal products). Different sources produce different structures of chondroitin, although the efficacy of chondroitin from all sources is thought to be similar.[1]
Another difference between supplements is whether the quality and quantity of chondroitin in the supplement has been verified. Over-the-counter food supplements are not monitored, and one study noted that these can contain far less chondroitin than stated on the label, and in some cases almost none.[2] With this in mind, people interested in supplementing with chondroitin to ameliorate osteoarthritis should consider seeking a prescription for pharmaceutical products, if any are available.[3][4]