My toy poodle will be 11 in May. this once-sluggish dog wiggles around like a puppy again. He eyes don't run, but he sure does, and he jumps 4 feet in the air. No one believes his age. If I run out of Pawier, after a week or so he slows down like his batteries are low. As soon as the new bottle arrives, my dog reverts to his post-Pawier wildman-energy level. We LOVE it!