Benzisothiazolinone

Benzisothiazolinone (BIT) is a synthetic preservative belonging to the isothiazolinone family. It works by inhibiting microbial growth, helping to prevent bacterial and fungal contamination in skincare formulations. This allows products to remain stable and safe throughout their shelf life without spoilage.The ingredient is used across a range of consumer and industrial products, though its prevalence in cosmetics has been subject to increasing scrutiny in recent years due to rising reports of contact sensitivity.

Benzisothiazolinone functions as an antimicrobial agent by disrupting microbial cell function and growth. When incorporated into a formulation, it acts as a preservative system to inhibit the proliferation of bacteria and fungi that could otherwise compromise product safety and stability.The ingredient works directly within the product itself rather than on the skin, making its primary role protective rather than therapeutic for skin health.

Benzisothiazolinone is a preservative system used by manufacturers during formulation; you do not need to adjust how you use products containing it. If you have sensitive skin or a known history of contact allergy, consider patch testing a product on a small area of skin before full application, or consult your dermatologist if you experience unexplained irritation after introducing a new skincare product.

Benzisothiazolinone is approved for use in cosmetics across most regions within specified concentration limits. However, contact allergy to this ingredient has been increasing, particularly among individuals with occupational exposure or pre-existing skin sensitivities. Those with known isothiazolinone sensitivity should avoid products containing this preservative.