Protein Nutrition Shake. Contains No Milk. Includes Milk Proteins. Gluten Free. Why do you workout? Is your season on the line? You have a big race coming up? You want to push you mind and body to test the outer limits of human determination? Or are you just trying to squeeze a little more cardio into your work week? It doesn't matter. We all need strength. And drink Muscle Milk after your workout helps build strength.