Benzisothiazolinone, commonly abbreviated as BIT, is an isothiazolinone-based antimicrobial ingredient identified by the INCI name BENZISOTHIAZOLINONE. Its chemical identity is 1,2-Benzisothiazol-3(2H)-one, CAS Number 2634-33-5, and EC Number 220-120-9. COSMILE Europe describes Benzisothiazolinone primarily as an antimicrobial ingredient, with functionality related to controlling the growth of microorganisms.
Benzisothiazolinone is valued for its antimicrobial activity and has historically been associated with preservation of water-containing formulations and other formulated products. Its use, however, must be distinguished from unrestricted cosmetic-preservative use because regulatory treatment varies by market and application.
Benzisothiazolinone is a heterocyclic compound with the molecular formula C₇H₅NOS and molecular weight 151.19 g/mol. PubChem identifies 2634-33-5 as the CAS number and lists synonyms including Benzisothiazolinone, Benzisothiazolone and 1,2-Benzisothiazol-3(2H)-one.
Reference chemical data report a melting point of approximately 156.6°C, with published ranges around 155–160°C. Tokyo Chemical Industry lists a specification of minimum 98.0% purity by GC for its research-grade material and a melting point specification of 155–160°C. These are supplier-specific reference values and should not automatically be treated as the specification of every commercial cosmetic grade.
Published data also report water solubility of approximately 1.1 g/L at 20°C, with measured values varying with pH. A recent study reported 1.288 g/L at 20°C and pH 6.7, illustrating why formulation conditions can influence handling and solubility behaviour.
Benzisothiazolinone provides antimicrobial functionality, helping control the growth of microorganisms such as bacteria and fungi. COSMILE Europe lists its cosmetic function as antimicrobial and also identifies a fragrance-functional role as an excipient in perfume oils and/or flavours.
For technical formulation work, BIT is generally considered in relation to microbiological control rather than as a conventional conditioning, emollient or sensory ingredient. Its incorporation into a formulation depends on the material concentration, preservation strategy, formulation pH, compatibility and the regulatory status of the finished product.
Benzisothiazolinone is also a recognized contact-sensitising substance, so appropriate safety evaluation and regulatory review are important when considering its use in products intended for consumer exposure. COSMILE Europe notes that the substance can be evaluated by patch testing where contact allergy is suspected.
Benzisothiazolinone has been associated with antimicrobial preservation applications in a variety of formulated systems. Cosmetic-industry references describe its use in water-based formulations, while broader industrial applications include coatings, adhesives, inks and other aqueous systems.
For cosmetic ingredient development, BIT may be evaluated where microbial control is required and where the substance is permitted for the intended market and product category. Application-specific suitability should be established from the finished formulation, applicable regulatory framework and safety assessment.
It is important not to automatically apply historical cosmetic-use levels to current products. A previous SCCS assessment considered a maximum authorised concentration of 0.01% in cosmetics from a systemic-toxicity perspective, but this should not be interpreted as a current universal EU cosmetic-preservative authorization. The SCCS document itself noted that BIT was not then listed as an authorized preservative.
When Benzisothiazolinone is considered for a cosmetic formulation, the actual commercial grade, active concentration, pH, compatibility, preservative system and intended product category should be reviewed together. The concentration of BIT in a supplied raw material is not the same as its concentration in the finished formulation.
Because BIT has sensitising potential, formulation developers should conduct appropriate safety and regulatory assessment before use. The current European cosmetic framework is particularly important: the EU Annex V allowed-preservative database does not list Benzisothiazolinone among its permitted cosmetic preservatives, while COSMILE Europe currently identifies the ingredient as antimicrobial rather than presenting it as an Annex V preservative.
As a B2B Benzisothiazolinone Cosmetic Ingredient Manufacturer in India page, this product can be positioned for technical evaluation by cosmetic, personal-care and specialty-formulation manufacturers requiring an antimicrobial raw material. Buyers searching for a Benzisothiazolinone supplier in India should review the chemical identity, active concentration, analytical method, physical characteristics and batch-specific documentation before selecting a grade.
For bulk cosmetic ingredient procurement, the commercial specification should be matched to the intended application and destination market. This is especially important for Benzisothiazolinone because regulatory treatment differs between cosmetics and other product categories such as industrial biocidal applications.
| Parameter | Specification |
|---|---|
| Appearance | White or colourless crystals / white powder |
| Loss on Drying | NMT 1.0% |
| Residue on Ignition | NMT 0.5% |
| Water Content | NMT 1.0% |
| Melting Point | 155–160°C |