USN's Muscle Fuel Mass is a high calorie/high carb version of the original Muscle Fuel formulation, designed for use by those with a high training intensity (over 12 hours per week) or those wishing to gain muscle mass. Consisting of USN's original protein blend with high levels of BCCA's and glutamine and 100 grams of carbohydrates per serving. The carbohydrate blend consists of high quality maltodextrin sourced from natural corn and fructose (fruit sugar) which has shown to replace hepatic (liver) glycogen without spiking insulin. USN's Muscle Fuel Mass is an advanced muscle mass building formula that is designed for active people who require top quality protein, complex carbohydrates, and other essential nutrients for optimum health and muscle performance.