There are 20 natural occurring amino acids that make up all the proteins in the human body. Muscle is made up of cells capable of contraction and relaxation in order to effect movement. There are 3 main types of muscle: skeletal, smooth and cardiac. Skeletal muscle is composed of muscle cells (fibers), each in turn made up of contractile elements called myofibrils. Human growth hormone (HGH), a 191 amino acid long peptide/protein is produced at its peak during puberty, reaching a peak at around 18-25, and then gradually decreasing with age until at about 55-60 years old, the amount of HGH is only about 25% of its peak. HGH stimulates muscle build up.
The nutrition industry offers through health stores, a number of protein powders, mainly derived from soy or whey. The more processed the powder the more expensive; processed normally refers to how hydrolyzed is the protein. We now that when we consume /ingest protein in our meals, the catabolic process (degradation) in the stomach sac, through a number of digestive enzymes and hydrochloric acid, chews down the proteins all the way down to amino acids, which then are absorbed in the intestines to be distributed and absorbed by our cells and be used anabolically (to construct) the proteins that our body needs.
Therefore, the more hydrolyzed the protein powder is, the less work our stomach has to do and the more easily absorbable it is, and the more they charge for it. SO the question is: is it worth it to pay the premium for the more highly processed product. And the answer may be, that it depends , most young, healthy individuals will able to process protein at their normal rate and obtain muscle growth with the proper training; on the other hand if the object is to speed up that muscle growth, one can argue that the bioavailability of the more processed powder may justify the added cost. So each person has to weigh and analyze the cost/benefit factor that best suits their purpose.