Essential Amino Acid Definition

Methionine is an essential amino acid.
Methionine is an essential amino acid. Todd Helmenstine
by Anne Marie Helmenstine, Ph.D.
Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels.
Updated March 06, 2017

Definition: An essential amino acid is an amino acid which an organism needs to ingest because it is necessary for nutrition and cannot be synthesized in the body.

Also Known As: indispensable amino acid

Examples: Isoleucine and leucine are examples of amino acids which are essential amino acids in humans.