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

QUASSIN

Safety grade: A

Quassin is a bitter compound extracted from the wood of tropical quassia trees. It's added to cosmetics as an unpleasant-tasting agent to discourage accidental ingestion, particularly in products not meant to be swallowed.

This ingredient is used as a denaturant to make cosmetic products taste extremely bitter, preventing people from accidentally consuming products like nail polish or other non-oral cosmetics.

Graded using: COSING.

Last verified: May 26, 2026