Quaternium-15

Quaternium-15 is a synthetic antimicrobial agent used primarily as a preservative in cosmetics and skincare products. It works by disrupting microbial cell membranes, preventing the growth of bacteria, fungi, and other microorganisms that could otherwise compromise product safety and stability.As a preservative, its role is functional rather than therapeutic—it protects the product itself from contamination during manufacture and use, ensuring the formula remains safe and effective throughout its shelf life.

Quaternium-15 is a cationic (positively charged) antimicrobial compound. It works by interacting with the negatively charged membranes of bacteria and fungi, disrupting their cell structure and preventing reproduction. This preservative action occurs at the product level rather than delivering direct benefits to the skin itself.

Quaternium-15 is a preservative, so you will encounter it as part of formulated products rather than using it as a standalone ingredient. Check product ingredient lists if you are avoiding this preservative; it will appear in the INCI declaration. If you have sensitive skin, introduce products containing it gradually and monitor your skin's response.

Quaternium-15 is generally well-tolerated at approved concentrations (up to 0.2%). Some individuals with sensitive skin or a history of contact dermatitis may experience irritation or sensitisation; if this occurs, discontinue use.