METHYLISOTHIAZOLINONE

CAS 2682-20-4 · preservative · EC 220-239-6 · KR 메칠이소치아졸리논

Generally Low Concern5 citations

2-Methyl-2H-isothiazol-3-one

METHYLISOTHIAZOLINONE is a preservative ingredient used in skincare formulations.

preservative; increasingly restricted/avoided due to sensitization concerns

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Quick facts

Description: METHYLISOTHIAZOLINONE — preservative; increasingly restricted/avoided due to sensitization concerns.

All Functions: preservative; increasingly restricted/avoided due to sensitization concerns

Quick Facts:

Category: preservative

Proven Benefits At A Glance:

Methylisothiazolinone (MI) is a preservative used in water-based personal care products
MI was named Contact Allergen of the Year in 2013 by the American Contact Dermatitis Society
Contact allergy to MI has increased significantly in recent years, described as an ‘epidemic’ in Europe and other regions
Standard patch tests using the MCI/MI combination miss approximately 40% of MI-only allergies
MI is also found in some household products, industrial chemicals, paints, and adhesives—not just cosmetics
If you have a confirmed MI allergy, dermatologists recommend avoiding products labeled with this ingredient

Chemical Overview

Chloromethylisothiazolinone is a 1,2-thiazole that is 4-isothiazolin-3-one bearing a methyl group on the nitrogen atom and a chlorine at C-5. It is a powerful biocide and preservative and is the major active ingredient in the commercial product KathonTM. It has a role as an antimicrobial agent, a xenobiotic and an environmental contaminant. It is an organochlorine compound and a member of 1,2-thiazoles. It is functionally related to a methylisothiazolinone. The Panel concluded that the ingredient mixture MCI/MI is safe in cosmetics when formulated to be non-sensitizing, based on the results of a QRA or similar methodology; however, at no point should concentrations exceed 7.5 ppm in leaveon products or 15 ppm in rinse-off products. Methylchloroisothiazolinone (MCI) is an isothiazolinone commonly used as a preservative with antibacterial and antifungal properties. It is found within many commercially available cosmetics, lotions, and makeup removers. It is also a known dermatological sensitizer and allergen; some of its side effects include flaky or scaly skin, breakouts, redness or itchiness, and moderate to severe swelling in the eye area. The American Contact Dermatitis Society named Methylchloroisothiazolinone the Contact Allergen of the Year for 2013. Sensitivity to Methylchloroisothiazolinone may be identified with a clinical patch test.

Source(s): DrugBank, ChEBI, Cosmetic Ingredient Review (CIR), via PubChem