Isothiazolinones (MIT/MCIT) in cosmetics: why it's flagged
Short answer
Isothiazolinones (MIT/MCIT) is flagged by Olive Detective as a moderate concern in cosmetics. Preservatives; potent contact allergens (rinse-off only in EU). The flag is class-level and precautionary, based on SCCS; “Allergen of the Year” 2013 — it describes the ingredient class, not the safety of any particular product.
What the concern is
- Allergen — a recognised contact-allergy or sensitisation risk.
- Irritant — can irritate skin, eyes or the respiratory tract.
How it appears on an INCI list
Cosmetic labels use INCI names, which are standardised worldwide, so the same wording appears on a product bought anywhere. This class is matched on methylisothiazolinone, methylchloroisothiazolinone.
How it affects the score
Cosmetic scoring follows the Yuka method: a product with only green and yellow ingredients has its score floored at 50, any orange ingredient caps it below 50, and any red caps it below 25. This ingredient is orange, so it caps a product's score below 50 on its own.
Source: SCCS; “Allergen of the Year” 2013
Other cosmetic ingredients we flag
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