Build solid muscle mass! Opto Mass Gainer features 40 grams of protein enriched with EAAs, BCAAs, and glutamine to help build and repair your hard-working muscles. This powerful formula is loaded with nutrient-dense calories derived from high-quality, fast, medium, and slow-digesting proteins and healthy fats. Energetic complex carbohydrates will give you quick-burning fuel to satisfy your energy demands. Digestive enzymes will assist digestion of the protein and make it readily available to your muscles.