What it is
Benzalkonium Chloride is a mixture of alkylbenzyldimethylammonium chlorides.
What it does
Benzalkonium Chloride is a preservative: it kills bacteria and prevents them from growing in cosmetic products.
In addition, it is also used as a foam booster and as a cleansing agent, helping water mix with dirt and oil so that they can be rinsed away.
Benzalkonium Chloride can cause irritations in some people.