1. Whey Protein constitutes approximately 20% of the total protein found in milk. Protein supplementation is used by athletes to promote positive nitrogen balance throughout the day without dramatically increasing caloric intake  . Specifically, it is reported that whey protein may help build muscles, increase strength, control appetite, aid in weight loss, improve endurance, and boost energy levels  .

2. Casein is a protein derived from milk products. It is used primarily by athletes to increase muscle mass and strength, control appetite, aid in weight loss, improve endurance, and boost energy levels. It provides all of the amino acids necessary for growth  .  Natural Gym Fat Burner Supplement Casein protein forms a gel in the stomach, which allows it to be digested more slowly so the peptides/amino acids are absorbed steadily over a long period of time, unlike whey protein, which is absorbed very quickly  .