Cationic Conditioning Agents (Conditioner Quats)
behentrimonium chloride/methosulfate · cetrimonium chloride · stearamidopropyl dimethylamine
What it is
The positively charged agents that actually condition hair, binding to the negatively charged, damaged hair surface to smooth and detangle it. They are quaternary ammonium compounds, but used at low concentration in rinse-off products.
In this product: Hair-conditioning and antistatic agents, the core of what a conditioner does.
Dose & route, what actually matters
Used at low concentration, rinsed out, with negligible systemic exposure. Irritation potential rises only at high leave-on concentrations the industry stays under. The asthma signal tied to quats comes from aerosolizing concentrated disinfectant quats into the air, not from rinsing a conditioner out of your hair.
EUROPEAN UNION
The SCCS assessed cetrimonium and behentrimonium chloride as safe within set concentration limits for rinse-off and leave-on hair care; stearamidopropyl dimethylamine is not restricted.
UNITED STATES
CIR assessed the trimonium conditioning agents as safe at current use when formulated to be non-irritating.
The evidence
The CIR Expert Panel assessed 52 trimonium conditioning agents (including behentrimonium and cetrimonium chloride) as safe at current practices of use when formulated to be non-irritating.
regulatory · 2012 · source
A clinical study confirmed behentrimonium chloride at 1-5% caused no dermal irritation or delayed contact sensitization even in a whole-body leave-on formulation.
human · 2013 · source
California Prop 65: Not listed.
How to avoid it
No real need to. These are the ingredients doing the conditioning, and they are well-tolerated in rinse-off use. If you are prone to reactions, patch-test leave-in products, where concentrations and contact time are higher.
Where it hides
Editorial analysis of publicly available regulatory and peer-reviewed sources. Not medical advice. We name our evidence and link it, including when an ingredient is fine.