Product Knowledge

BIT 20% as a Cosmetic & Personal Care Preservative

Benzisothiazolinone is used as a preservative in select personal care and cosmetic formulations, but its use is more tightly regulated than in industrial applications. This guide covers what formulators must check before using BIT in a cosmetic product.

Published 2026-01-15Updated 2026-07-27By Vasudev Chemo Pharma Technical TeamReviewed by Vasudev Chemo Pharma Formulation & Regulatory Affairs Team, Industrial Chemistry, Biocide Formulation

Is BIT Approved for Use in Cosmetics?

Benzisothiazolinone's cosmetic use is regulated by jurisdiction and is not currently listed on the EU Cosmetic Regulation Annex V with a dedicated concentration limit the way MIT and CMIT/MIT are. Always check the current CosIng database entry for BIT before finalising a cosmetic formulation.

Formulators must check the current permitted concentration limit in their specific target market's regulatory database — such as the EU CosIng database, or the relevant national cosmetic regulation — before finalising a formulation, since limits are reviewed periodically and can change. Some regional cosmetic ingredient reviews have historically evaluated benzisothiazolinone alongside other isothiazolinones due to shared sensitisation concerns within the chemical family, even though BIT's own reported sensitisation rate is generally lower than some other isothiazolinones such as CMIT in published assessments. This distinction matters for risk communication but does not exempt a formulation from applicable concentration limits.

What Personal Care Applications Use Benzisothiazolinone?

Where permitted, benzisothiazolinone-type preservatives have been used in select shampoos, conditioners, body washes, and liquid hand soaps, generally at the lower end of typical isothiazolinone dosage ranges given cosmetic-specific concentration limits.

Rinse-off products (shampoo, body wash, hand soap) generally carry a different risk profile than leave-on products (lotions, creams) due to shorter skin contact time, and regulatory concentration limits often reflect this distinction with different permitted levels for each category — confirm current limits for your specific product category and target market before formulating.

What Should I Check Before Formulating BIT Into a Cosmetic Product?

Use cosmetic-grade material meeting tighter impurity and colour specifications than industrial grade, validate dosage through preservative efficacy testing under ISO 11930, and consider patch-testing finished products as part of standard cosmetic safety assessment.

Cosmetic-grade benzisothiazolinone raw material should meet tighter impurity and colour specifications than standard technical/industrial grade material. Always request cosmetic-grade material with an appropriate specification and supporting documentation when formulating for personal care use. Dosage should be validated through preservative efficacy (challenge) testing specific to your formulation, following ISO 11930 or your target market's equivalent standard, rather than relying solely on generic industry dosage ranges. Given the sensitisation profile of the isothiazolinone family generally, formulators should also consider patch-testing finished products as part of a broader safety assessment process before market launch.
Cosmetic formulation checklist for benzisothiazolinone-type preservatives
StepRequirement
Raw material gradeCosmetic-grade specification, not technical/industrial grade
Concentration limitVerify current limit on EU CosIng database or target market's register
Efficacy validationPreservative efficacy test under ISO 11930 or equivalent standard
Safety assessmentPatch testing on finished product as part of standard cosmetic safety assessment

Frequently asked questions

Is BIT approved for use in cosmetics?+
Benzisothiazolinone's permitted use and concentration limits in cosmetics vary by jurisdiction and are subject to periodic regulatory review. Check the current CosIng database entry before formulating — do not rely on general guidance alone.
Is BIT safer than other isothiazolinones for cosmetic use?+
BIT has a generally lower reported sensitisation rate than some other isothiazolinones such as CMIT in published assessments, but it remains classified as a sensitiser and is still subject to specific regulatory concentration limits in cosmetic use.
What is the difference between rinse-off and leave-on cosmetic preservative limits?+
Rinse-off products generally have shorter skin contact time than leave-on products, and regulatory concentration limits for preservatives like BIT often reflect this with different permitted levels per category. Confirm the specific limit for your product category and market.
Do I need cosmetic-grade BIT for personal care formulations?+
Yes, cosmetic-grade material meeting appropriate impurity and colour specifications is recommended for personal care formulations, rather than standard technical/industrial grade material.

Sources

  1. European Chemicals Agency — Cosmetics preservatives list (CosIng)
  2. ISO 11930 Preservative Effectiveness Test overview (Microchem Laboratory)