Whey protein concentrate is the fraction of milk protein left after cheese making, dried to a powder that is roughly 80% protein with small amounts of lactose and milk fat. It digests fast and carries more leucine than almost any whole food, which is why it is the default choice around training. A typical scoop is 25-30 g and delivers 20-25 g of protein. It is food, not a drug: the same protein can come from milk, eggs or meat, and the powder only makes the daily total easier to reach.