Mine has arthritis in his hocks and a chip in the knee which I'm sure is accompanied by some arthritis. I've been feeding him Tight Joints Plus and he's been doing really well on it. I did have him on Pentosan before but I didn't really see a huge improvement and I had to inject IV so I didn't repurchase when I ran out. I'd definitely try Adequan again as we've used it on a 20+ horse and he was used until he was 30 and he felt GREAT on it.