The truth is that I didn't expect it to "work." It was recommended to me by a veterinarian... so that my dog would have an appetite for food. Indeed, after about 5 days of taking it... he started eating the recommended amounts of food.

I gave it to a 19-year-old cocker spaniel with walking problems due to arthritis and also to boost his energy. After a week, his walking and mood improved. I believe it was worth the purchase.