All organisms from the largest to the smallest are composed of proteins.
Amino acids are molecules that are the 'building blocks' of protein.
In the human body, muscles, tendons, ligaments, glands, organs, nails, hair, body fluids, hormones, enzymes, neurotransmitters and genes all require protein. Amino acids link together in the human body to form over 50,000 different proteins and 20,000 known enzymes. Amino acid molecules contain a combination of carbon, hydrogen, oxygen, nitrogen and in some cases sulfur. Approximately 28 known amino acids comprise the proteins in all living things. Nine amino acids are considered 'essential,' meaning the body cannot produce them so they must be taken in by diet or supplement.