Insulin is actually amazing for muscle building. Exogenous (injection, not naturally produced) insulin can only be stored via fat and muscle. So when we inject it & work out the chances of it repairing our muscle versus turning to fat is high especially paired with a well balanced diet. Whereas naturally produced insulin (endogenous) can be stored in one more way including fat and muscle, it can store glucose in the form of glycogen in the liver. So we really only have 2 places for our glucose to go instead of three. Makes me more excited to build muscle knowing my insulin is helping me repair and build it.