QUATERNIUM-91 is graded A (Safe) by Expert·ING, based on COSING regulatory data.

QUATERNIUM-91

Safety grade: A

Quaternium-91 is a conditioning agent derived from natural plant oils that has been chemically modified to help manage and soften hair. It works by coating the hair shaft to reduce frizz and improve manageability.

This ingredient is used in hair care products to condition and detangle hair, making it smoother, shinier, and easier to comb while reducing static and flyaways.

Graded using: COSING.

Last verified: May 26, 2026