Benzisothiazolinone warrants attention because the checked official assessment identifies contact-sensitisation concerns. The evidence does not establish a clear general seb derm recommendation or a sensitisation threshold that would make every cosmetic exposure acceptable.

The EU’s approved cosmetic preservative list does not include this exact substance, so it cannot be used there as a cosmetic preservative. That use-scoped rule is distinct from an unconditional prohibition on every function. Patch-test findings come from selected dermatitis patients and cannot predict your personal risk. If you have a known allergy or a product containing it causes persistent irritation, ask a clinician or pharmacist for advice.