Fletcher has been on Fresh Factors for a few years, and recently started Joint Health. I've started Molly also, as they are both now 7, even though she has no symptoms. I used Cosequin for Sugar, her arthritis was much worse, and for the last year or so, Dasequin. It's made by the Cosequin people, but has added "stuff", and is prescription only. It was very helpful when her arthritis and spinal problems got really bad.
I know glucosamine helping arthritis is considered anecdotal, but it has really made a difference for me!