Methylisothiazolinone
INCI: METHYLISOTHIAZOLINONE
Also known as: MI, MIT, Neolone 950
Key Facts
- CAS Number
- 2682-20-4
- Category
- preservative
- Risk Level
- high
- Common Allergen
- Yes
- EU Status
- Restricted
- Max Concentration
- 0.0015% (rinse-off only, leave-on banned)
- Found In
- shampoo, conditioner, body wash, cleaning products
Is Methylisothiazolinone safe in cosmetics?
Methylisothiazolinone is rated high risk in cosmetic products. It is a known allergen that can cause contact dermatitis in sensitized individuals. Preservative linked to high rates of allergic contact dermatitis. The most common cosmetic allergen identified in patch testing. This ingredient is restricted under EU cosmetic regulations. Safer alternatives include Phenoxyethanol, Sodium Benzoate, Potassium Sorbate. Commonly found in shampoo, conditioner, body wash.
What is Methylisothiazolinone?
One of the most common contact allergens in cosmetics. Banned in leave-on products in the EU since 2016.
Allergy & Safety Information
Methylisothiazolinone is classified as a high-risk ingredient. It is a known cause of allergic contact dermatitis. It is restricted or regulated in the EU. Individuals with sensitive skin or a history of contact allergies should avoid products containing this ingredient. A patch test is recommended before first use of any product containing Methylisothiazolinone.
Cross-Reactions
If you react to Methylisothiazolinone, you may also react to:
Safer Alternatives
These ingredients serve a similar function with lower allergy risk:
Frequently Asked Questions
Is Methylisothiazolinone safe for sensitive skin?
Methylisothiazolinone is a known allergen and is generally not recommended for sensitive skin. Consider patch testing before use.
What products contain Methylisothiazolinone?
Methylisothiazolinone is commonly found in shampoo, conditioner, body wash, cleaning products.
What does Methylisothiazolinone do in cosmetics?
Methylisothiazolinone functions as a preservative in formulations. Preservative linked to high rates of allergic contact dermatitis. The most common cosmetic allergen identified in patch testing.
Related Guides
Top 10 Cosmetic Allergens
Is Methylisothiazolinone on the list? See the full clinical ranking.
Preservative Allergy Guide
Which preservatives cause the most reactions and what to use instead.
How to Read Ingredient Labels
Decode INCI names and find hidden allergens in your products.
Find Your Skin Allergy Trigger
Step-by-step elimination method to identify your trigger.
Contact Dermatitis Guide
Symptoms, causes, patch testing, and treatment options.
Is Methylisothiazolinone causing YOUR skin reactions?
SkinDetekt tracks your products and reactions to find your personal triggers. Download the app to find out.
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