This rock solid mass gainer is engineered with the ingredients proven to help increase lean muscle mass, weight, strength and endurance. You can get even more out of every workout session when you make GNC AMP Mass XXXâ„¢ a part of your exercise routine. 50g of fast, medium and slow digesting proteins, along with 10g of BCAA, 748 calories, plus carbohydrates and healthy fats for science-based nutrition. Addition of 3g of creatine may help improve training results and supports muscle protein synthesis. Micronized amino acids help fuel muscles and might support key processes crucial to the growth and repair of muscle. Gluten-free dietary supplement