Essential Amino Acids: Complete Guide

Essential amino acids are the amino acids humans must obtain from food because the body cannot make enough of them to meet physiological needs.

The nine essential amino acids

The commonly recognized essential amino acids for adults are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine.

EAAs and protein

A complete dietary protein supplies all essential amino acids. Free-form EAA supplements deliver them without the rest of the intact protein matrix. The body ultimately uses amino acids for tissue proteins, enzymes, signaling molecules and many other functions.

EAAs and muscle

Leucine is an important signal for muscle protein synthesis, while the full complement of necessary amino acids supplies building blocks. Research in older adults suggests the response to protein or amino acids can be blunted with age, a phenomenon often called anabolic resistance.

Do you need a supplement?

Not necessarily. Many people can meet needs through a varied diet containing adequate protein. Supplements may be convenient when appetite, food tolerance, schedule or serving-volume preferences make ordinary protein intake harder.

What to compare on an EAA label

Look at the amino-acid profile, dose transparency, serving format, added ingredients, price per serving and whether the company makes claims that exceed the evidence.

Continue this topic

• What Do Essential Amino Acids Do?
• EAA vs BCAA
• EAA vs Protein Powder