Quaternium Ammonium Compounds
Reviewed by Rosie · Last updated 18 Aug 2026
Also known as: guar hydroxypropyltrimonium chloride, dicetyldimonium chloride, dihydrogenated tallow benzylmonium chloride, behentrimonium chloride, behenalkonium betaine, benzalkonium chloride, quaternium 18, stearalkonium chloride, cetrimonium chloride, and many more
A wide range of ingredients, called “quats” for short | Share a unique molecular structure that makes them strongly attracted to hair
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EWG Safety Score
What Is Quaternium Ammonium Compounds?
A wide range of ingredients, called “quats” for short, that share a unique molecular structure that makes them strongly attracted to hair. When one end of the quat grabs the hair, the other end sticks out, providing a handle for another quat molecule to grab onto. This linking creates a lineup on the hair that resembles a temporarily smooth surface, allowing combs and brushes to more easily glide through hair. Found primarily in shampoos, rinse-off and leave-in conditioners, and any product that claims to detangle the hair, these less-than-poetic-sounding ingredients are essential for having manageable hair.
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Quaternary Ammonium Compounds
A wide range of ingredients, called "quats" for short | Share a unique molecular structure that makes them strongly attracted to hair
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