Canadian researchers recently compared the pharmacologic properties of two different forms of glucosamine–hydrochloride and sulphate. They measured significantly higher levels of glucosamine in synovial fluid samples from horses receiving the oral glucosamine sulphate formulation as compared to synovial fluid levels in horses receiving oral glucosamine hydrochloride.

Glucosamine is a common ingredient in oral joint health supplements that are widely administered to horses with osteoarthritis. Glucosamine is available in a number of different forms including hydrochloride, sulphate, and N-acetyl-D-glucosamine. To date, there is conflicting evidence surrounding the use of glucosamine for the management of osteoarthritis, regardless of species.

"It has been proposed that the type of glucosamine used may impact efficacy," explained Sheila Laverty, MVB, Dipl. ACVS, professor and specialist in equine surgery in the University of Montreal’s Veterinary School. Laverty is also a member of the Canadian Arthritis Network.

A recent review article suggests that the most favorable clinical trial results of osteoarthritis in humans were associated with the use of glucosamine sulphate, which is currently available for human use by prescription only in European countries