Essential amino acids

Also known as EAA, EAAs, essential aminos.

Last reviewed October 9, 2026 · Jump to references

What is Essential amino acids?

In plain words

Essential amino acids are nine building blocks of protein that the body must get from food. The body uses them to make and repair muscle and other tissues, and to produce important chemical messengers. Researchers study EAA supplements for muscle maintenance and recovery, including during aging. Their nutritional importance is well established, but added benefits from supplements depend partly on a person's diet and health.

Technical definition

Essential amino acids (EAAs) are nine proteinogenic amino acids that humans cannot synthesize in sufficient quantities and must obtain from dietary sources: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. They serve as substrates for protein synthesis and precursors for other biomolecules; leucine also promotes mTORC1 signaling, a nutrient-sensing pathway involved in protein synthesis, rather than acting through a single dedicated EAA receptor. In the United States, EAA products are commonly marketed as dietary supplements and are not FDA-approved treatments for disease.

Educational information only. This page does not provide medical advice or determine whether a supplement is appropriate for you. Review supplements with a qualified healthcare professional, especially if you take medication, are pregnant, have surgery scheduled, or have a chronic medical condition.

Evidence by use

Each use is rated on its own. There is no single overall effectiveness score.