THREONINE is graded A (Safe) by Expert·ING, based on COSING, FDA regulatory data.

THREONINE

Safety grade: A

Threonine is an amino acid, which are the building blocks of proteins found naturally in your body and many foods. In hair care products, it helps strengthen and condition your hair while reducing static and frizz.

Threonine is used in hair products to improve texture, reduce static electricity, and help with hair conditioning, while also supporting the hair's natural structure during chemical treatments like perming or straightening.

Graded using: COSING, FDA.

Last verified: May 26, 2026