Encyclopedia · conditioning agent
Cetrimonium chloride
A shorter-chain conditioning ingredient, a bit less effective than the behentrimonium salts but lighter, found in many shampoos, light conditioners and sprays.
What it is
A quaternary ammonium salt with a 16-carbon tail. A related compound, cetrimonium bromide, is also used as an antiseptic.
How it works
The positive head binds negatively charged hair. In the 2026 Singapore comparison, it deposited and cut combing force less than the behentrimonium salts because of its shorter chain, but did better than bulky stearalkonium chloride. Tham 2026 In gel work, cetrimonium-based gels were weaker than behentrimonium-based gels. Davies 2020
What the studies show
- Moderate conditioning, below the behentrimonium salts, in lab tests on hair and silica. Tham 2026
- Lower gel strength than behentrimonium gels in a formulation lab. Davies 2020
How it's used in studies
EU limits for cetrimonium plus steartrimonium chloride together are 2.5% in rinse-off hair products and 1.0% in leave-on hair products (Regulation 2014/866).
Side effects and safety
An eye and skin irritant at high concentration, which is the reason for the regulatory caps. Rinse well from the scalp if you are sensitive.
Bottom line
A fine lightweight conditioning ingredient. Choose behentrimonium types for more slip on thick, curly or damaged hair. We are moderately sure of this ranking.
Studies 2
Tham HP et al. Electrokinetic analysis reveals common conditioner ingredient interactions with human hair. Int J Cosmet Sci. 2026
Tested: behentrimonium chloride and methosulfate, cetrimonium chloride, stearalkonium chloride
Result: Longer-chain behentrimonium chloride cut wet combing force and deposited best; none reversed oxidative damage.
Read the study ↗Davies AR, Amin S. Microstructure design of CTAC:FA and BTAC:FA lamellar gels using an automated formulation platform. Int J Cosmet Sci. 2020
Result: Gel structure strength was highest for behentrimonium systems, peaking at a surfactant to fatty alcohol ratio of 6:10, and it affected wet combing.
Read the study ↗Related
- Behentrimonium chlorideA long-chain, positively charged conditioning ingredient that clings to hair and detangles it, with good lab evidence for smoothing and none for repair.
- Behentrimonium methosulfateThe methosulfate salt of the same C22 conditioning ingredient as behentrimonium chloride, slightly weaker in head-to-head lab testing.
- Cetyl alcoholA 16-carbon fatty alcohol that thickens conditioners and pairs with conditioning surfactants to form the gel; it is not a drying alcohol.
- How conditioner worksRinse-off conditioner coats hair with a positively charged layer that cuts friction and tangling; it does not repair structural damage.