Behentrimonium methosulfate

Behentrimonium methosulfate (CAS 81646-13-1), also known as docosyltrimethylammonium methyl sulphate, is a quaternary ammonium compound used primarily in rinse-off and leave-in hair care formulations.

Where is Behentrimonium methosulfate used?

• Hair conditioners and conditioning masks: emulsifies fatty alcohols
• Cetyl and stearyl alcohol systems: forms the cream base while depositing conditioning actives onto the hair shaft
• Leave-in treatments and detangling sprays: cationic charge binds to damaged hair
• Curl creams and styling butters: stable, rich textures with controlled rheology
• By binding to negatively charged hair, it reduces friction and improves combability.
• In skin formulations, acts as primary emulsifier, stably incorporating the oil phase while leaving a soft, non-greasy feel.
• In rinse-off conditioners, used at 2–5% for conditioning and detangling.
• Used in hair conditioner bars, zero-waste hair products, and sustainable beauty products.

Good to know: It functions as a cationic emulsifier and conditioning agent, enabling stable emulsion formation while imparting detangling and softening effects to hair fiber. Preferred in sulfate-free and mild systems where compatibility with sensitive scalp claims is required.

Formulation notes

• Recommended usage amount is 1% to 10%.
• Typical use level in leave-in treatments is 1–3% for light conditioning.
• Typical use level in hair masks is 3–6% for deep repair and softness.
• Typical use level in 2-in-1 shampoos is 0.5–2% to improve combability.
• The formulation is cooled below 45 °C before adding fragrances or sensitive actives.

Typical specification

• Cetearyl Alcohol content is 73–77%.
• pH of a 1.0 wt% isopropanol solution is 6–8.
• Free amine content is less than 0.8%.
• Softening point is around 50°C and it remains stable around 120°C.

Regulatory status

• It is CLP-labelled under EU Regulation 1272/2008 for hazard communication.
• It causes skin irritation (H315).

Frequently asked questions about Behentrimonium methosulfate

What are the differences between BTMS-25, BTMS-50, and BTMS-80 grades?

BTMS-25 contains 25% of the active ingredient behentrimonium methosulfate, while BTMS-50 contains 50%. BTMS-80 has a higher proportion of behentrimonium methosulfate for formulations requiring higher active conditioning content.

What is the INCI name for behentrimonium methosulfate?

The INCI name for behentrimonium methosulfate is Behentrimonium Methosulfate (and) Cetyl Alcohol (and) Butylene Glycol.

Is behentrimonium methosulfate considered safe for cosmetic use?

According to the Cosmetic Ingredient Review Expert Panel, behentrimonium methosulfate is safe for use in current practices and concentrations.

Technical content is compiled and updated by the SoleChem product team from public technical sources; the certificate of analysis (COA) governs product-specific specifications.