I didn't do any scientific studies with a control group or anything, but this seems to work. I've been giving it to my older dog (8 year old lab mix) for about a week. This morning, she came bouncing in for breakfast, hopping on and off the couch like a puppy and it occurred to me that I have seen a change in her behavior.In the past, she would put her front feet up on the couch and hop a few times as if she was planning how to get up before joining us. Lately, she is just launching herself from a walk. It is as if she shed a few years.Again, I can't prove it was this supplement, but I haven't changed her diet in any other way.