 Differently than in Europe and other countries, glucosamine formulations are marketed in the United States as dietary supplements. They include glucosamine sulfate substances different than the original prescription preparation, other glucosamine salts mainly glucosamine hydrochloride, and are administered according to different dosage schemes mainly as oral solid formulations that provide a total 1500 mg dose, but divided in three daily intakes, t.i.d.. In clinical trials conducted so far, these formulations failed to show the same efficacy of the original glucosamine sulfate prescription preparation. 