I purchased this for our 5 month old Border Collie-Black Lab mix rescue puppy after he seemed to be losing weight. Within 1week, his weight returned to normal with strong, lean muscle growth. Within 2 weeks, his coat was shining, and his hyperactivity seemed to mellow. (That might just be his getting older, but not sure). I am not one to overspend, but this product has been worth the money so far. I will continue to purchase this product.