When Should You Drink a Protein Shake?

Although protein shakes can be taken before and after a workout for nutritional and optimum muscle-building results, a preworkout protein drink is best, according to Dr. Mike Roussell at BodyBuilding.com. A protein drink with branch chain amino acids, or BCCAs, provides fuel for the workout while feeding the muscles protein.

Because BCCAs head directly into the blood stream after being absorbed in the stomach, bypassing the liver, they feed the muscles directly with proteins while the blood pumps during exercise. Roussell goes on to say that elevated levels of amino acid nutrients in the blood carry on up to three hours after the workout.