Benzalkonium chloride is an organic salt classified as a quaternary ammonium compound. In cosmetics and personal care products, benzalkonium chloride is primarily used as a preservative and antimicrobial agent, and secondarily used as a surfactant. As a preservative, benzalkonium chloride functions to prevent or inhibit the growth and reproduction of microorganisms in finished products. The use of preservatives in cosmetics is important because these types of products have a high potential for microbial contamination and growth. The antimicrobial properties of benzalkonium chloride also enable it to be used as an active ingredient in products such as hand sanitizers, soaps, and antibacterial hand wipes.

One problem with benzalkonium chloride are the concerns regarding its safety. According to EWG’s Skin Deep Cosmetics Database, benzalkonium chloride is associated with severe skin, eye, and respiratory irritation and allergies. Furthermore, benzalkonium chloride is a sensitizer that can be problematic for people with asthma or skin conditions such as eczema.