I have been using them for years. I use glucosamine and chondroitin . Joey broke his leg racing and his leg is fused. It was recommended that I put him on glucosamine. When I put him on it, I also put my female on it. I noticed that she seemed to feel better and wanted to walk more. She seemed to have more energy. When Joey's leg started bothering him, I tried the chondroitin and he has been doing fine since then.