I swear by it. My first experience was with my 4 year old poodle. She suffers from arthritis in her hind legs (worst in the winter). The vet put her on The Missing Link Vet Strength (contains stronger glucosamine) and truth be told..........she hasn't been in pain ever since. She has so much energy and plays all day long with the yorkie pup and cat.
I started my yorkie baby at 12 weeks on it too. He loves it and it hasn't caused anything wrong.
Since then, I started the cat of the feline version...........AND if they made a hamster version.........my lillie (the hamster) would be on it too!! LOL