Cetrimonium Methosulfate

What is Cetrimonium Methosulfate?

Cetrimonium Methosulfate is a quaternary ammonium compound, specifically the methosulfate salt of cetyltrimethylammonium, derived synthetically from long-chain fatty alcohols and quaternizing agents. It belongs to the cationic surfactant family, distinguished by its positive charge, which enables strong binding to negatively charged hair and skin surfaces. Primarily featured in rinse-off hair care products like conditioners and detanglers, it functions by forming a protective film that minimizes friction between hair strands. This action imparts smoothness and controls static electricity. Additionally, its surfactant properties aid in emulsifying oil-water mixtures for stable emulsions, while antimicrobial qualities help maintain product integrity by limiting microbial growth during storage.

Comedogenic Rating 0/5 Low risk of clogging pores
EWG Safety Rating 4 View on EWG →
PubChem View on PubChem →

Roles in Formulation

This ingredient serves the following purposes in cosmetic formulations:

Antistatic agent
Reduces static electricity and flyaways by improving surface conductivity, enhancing hair manageability and smoothness in conditioners and styling products.
Biocide
Destroys or inhibits harmful organisms to preserve products.
Surfactant
Lowers surface tension to enable cleansing, emulsifying, and foaming; central to shampoos, body washes, and many emulsions and micellar systems.
Emulsifying agent
Enables stable mixing of oil and water phases by forming an interfacial film, helping create lotions, creams, and cleansers with consistent texture.
Antimicrobial agent
Helps limit growth of bacteria and other microbes on skin or in the formula; may be used for product protection, odor control, or targeted antimicrobial effects.
Hair conditioning
Improves softness, shine, and manageability by reducing friction and static; commonly achieved with cationic agents, silicones, oils, or conditioning polymers.

Benefits

Enhances hair smoothness and reduces flyaways for better manageability.

Supports formula stability through emulsifying and antimicrobial actions.

Provides gentle cleansing without comedogenic concerns.

Who It's For

A quick guide for who this ingredient may suit (and who should be cautious).

Who May Benefit Who Should Avoid
Individuals with frizzy or static-prone hair seeking conditioning benefits.
Those with known sensitivity to quaternary ammonium compounds.
Users of hair products needing antistatic properties.
Individuals prone to contact dermatitis from cationic surfactants.
People looking for rinse-off formulas with built-in preservation.
People experiencing eye irritation from hair rinse-off products.

Safety Notes

  • Rated moderate concern by EWG, suitable in rinse-off products when formulated appropriately.
  • Non-comedogenic, unlikely to clog pores based on available ratings.

Frequently Asked Questions about Cetrimonium Methosulfate

What is Cetrimonium Methosulfate used for?

Primarily as an antistatic and conditioning agent in hair products to improve manageability and smoothness.

Is it safe for daily use?

Generally recognized as safe in rinse-off cosmetics when used within standard formulation guidelines.

Does it cause irritation?

Potential for mild irritation exists, especially for sensitive skin; best in rinse-off applications.