Cetrimonium Methosulfate

Cetrimonium methosulfate is a quaternary ammonium compound (QAC)—a type of positively charged surfactant derived from organic chemistry. It functions as an antimicrobial agent and is also used for its antistatic and conditioning properties in skincare and haircare formulations.In skincare products, it typically appears at very low concentrations (around 0.1% of formulations) and is primarily included for its ability to reduce microbial growth and improve product texture or feel.

Cetrimonium methosulfate works by disrupting the cell membranes of microorganisms. The positive charge of the molecule allows it to bind to the negatively charged bacterial cell wall, compromising its integrity and inhibiting microbial growth.In formulations, it also functions as a mild surfactant, meaning it can help distribute oils and water-based ingredients more evenly throughout a product.

This ingredient is typically found in finished skincare products rather than used as a standalone active, so usage frequency depends on the product type. If using a product containing cetrimonium methosulfate, follow the manufacturer's instructions. Discontinue use if redness, itching, or irritation develops, particularly on sensitive or compromised skin.

Generally well-tolerated at the concentrations used in cosmetics. However, quaternary ammonium compounds can cause irritation or allergic contact dermatitis in sensitive individuals, particularly at higher concentrations or with prolonged exposure.