What it is: Amino acids are the building blocks of proteins. There are 20 different amino acids that combine in various sequences to form all the proteins in the human body. Nine of these are considered “essential,” meaning the body cannot produce them and they must be obtained from food or supplements.
Common examples:
Essential amino acids: leucine, isoleucine, valine (BCAAs), lysine, methionine, phenylalanine, threonine, tryptophan, histidine
Non-essential amino acids: glutamine, arginine, glycine, proline, alanine
Why they matter: Amino acids are crucial for building and repairing muscle tissue, producing enzymes and hormones, supporting immune function, and maintaining overall health. Athletes often supplement with branched-chain amino acids (BCAAs) to support muscle recovery, while tryptophan is a precursor to serotonin, a neurotransmitter that affects mood and sleep.
In supplements: Available as individual amino acids (like L-glutamine or L-arginine), BCAA formulas, or complete essential amino acid (EAA) blends.
