O-PHOSPHOSERINE is graded A (Safe) by Expert·ING, based on COSING regulatory data.

O-PHOSPHOSERINE

Safety grade: A

A naturally derived amino acid compound that helps strengthen and protect your skin's outer layer. It works by supporting your skin's natural moisture barrier and can improve hydration and elasticity. You'll find it in serums and moisturizers designed to keep skin looking plump and healthy.

Graded using: COSING.

Last verified: June 9, 2026