I recommend SmartMuscle Mass Pellets. I started using it over a yr ago for a growing 2yr old appendix QH, now a coming 4yr old.My vet recommended I try a muscle builder. It didn’t change his energy level at all. It did add muscle to his top line, hind Qtrs. and neck. His over all appearance improved tremendously. I noticed a difference in a couple of weeks. He needed a little more weight,because how he was growing at the time. I also started him on a rice bran pellet,per the vets advice. The combination worked great for him.