FullBucket Medical Muscle is an antioxidant-rich formula designed to help with muscle function and is really at the frontier of products specially designed for horses that suffer from "tying up"(Exertional Rhabdomyolysis or ER), Recurring Exertional Rhabdomyolysis (RER), PSSM (Polysaccharide Storage Myopathy) or Medical Catabolism. Its unique formulation includes an antioxidant called Astaxanthin which is 6,000 times more powerful than Vitamin C! FullBucket Medical Muscle is one of the few products on the market specially designed for horses with severe muscle issues such as "tying up" and PSSM.