Cellucor COR-Performance Glutamine is the best glutamine supplement for muscle building. It will replenish the depleted glutamine levels to help your recover faster and build stronger. It supports muscle recovery and assists lean muscle growth. In a single serving, you’ll get 5g of L-Glutamine. Furthermore, you can purchase the unflavored option for perfectly mixing with your favorite beverage. In addition, you can always go for its delicious flavors, including Fruit Punch and Icy Blue Razz.