lysine

noun

ly·​sine ˈlī-ˌsēn 

: a crystalline essential amino acid C₆H₁₄N₂O₂ obtained from the hydrolysis of various proteins

Examples of lysine in a Sentence

Recent Examples on the Web

While quinoa is a complete protein, many grains are lower in lysine, an amino acid that is more abundant in legumes, dairy, eggs, and animal proteins. — Lynn Andriani, Martha Stewart, 30 May 2026

The other six essential amino acids required to build and repair muscle are histidine, lysine, methionine, phenylalanine, threonine, and tryptophan. — Shimite Obialo, Forbes.com, 26 May 2026

Regardless, this cheese is a complete milk protein and has a particularly high concentration of lysine, an essential amino acid necessary for building muscles, as well as calcium to support strong bones. — Philipp Wehsack, Vogue, 28 Mar. 2026

These amino acids include histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine – collectively necessary for building muscle, producing enzymes and hormones and maintaining healthy tissue. — Daryl Austin, USA Today, 21 Mar. 2026

Word History

First Known Use

1892, in the meaning defined above

Kids Definition

lysine

noun

ly·​sine ˈlī-ˌsēn 

: an essential amino acid obtained from various proteins

Medical Definition

lysine

noun

ly·​sine ˈlī-ˌsēn 

: a crystalline essential amino acid C₆H₁₄N₂O₂ obtained from the hydrolysis of various proteins

—abbreviation Lys