I've never used Cosequin but I have been using Dasuquin with MSM for almost 3 years. The only one who can tell me if it's really doing anything special doesn't speak english. I'm sure it helps him. I noticed that Cosequin comes in a formula with MSM - I might give it a try. However, you have to give twice as much Cosequin than Dasuquin. Dasuquin is definately a better value. Currently, I have my old guy on HylaSport Canine from www.pupsup.com
