Won't let my boy go without this now. He is a 9 year old cocker spaniel and, before this stiff, he was having obvious joint problems and seemed to be developing arthritis. He was in pain, hesitant, and slow to move. He wouldn't go up steps, walked slow and hung behind me on walks, etc. After just weeks on this, the difference was remarkable. No more pain...he is back to bouncing around like a puppy. It's been two months now with no recurrences.