METHYLISOTHIAZOLINONE
Commonly Found In
Overview
Methylisothiazolinone (MIT) is a biocide preservative that gained widespread use in the 2000s. It was designated Contact Allergen of the Year 2013 by the American Contact Dermatitis Society after a significant epidemic of contact allergies across Europe. The EU prohibited it in leave-on cosmetics in 2016 and restricts it to 0.0015% in rinse-off products. Canada banned it entirely in 2021.
Also known as: MIT, MI, 2-methyl-4-isothiazolin-3-one, Kathon CG (in blend with CMIT), Neolone
Key Benefits
Broad-spectrum preservative; no skin benefit. Clinical evidence indicates it is a potent skin sensitizer, responsible for a widespread contact allergy epidemic in Europe in the 2010s, particularly in leave-on formulations.
Supporting Research
- β’ SCCS/1521/13 (2014): SCCS concluded MIT is not safe at any concentration in leave-on cosmetics, leading to EU ban
- β’ Uter W et al. (2015): MI contact allergy epidemic documented across European dermatology clinics
- β’ American Contact Dermatitis Society (2013): Designated MIT as Contact Allergen of the Year
Skin Compatibility Ratings
Comedogenic Rating
Non-comedogenic; used alone or with MCI at very low concentrations.
Source: SCCS/1634/21; CIR Expert Panel
Irritancy Rating
High sensitization potential in leave-on products (banned in EU). Lower risk in rinse-off at 0.0015% but still significant sensitizer. Score of 3 applies to leave-on exposure.
Source: SCCS/1521/13; ACDS 2013
Typical Use Concentration
Range
0.0001β0.0015% (EU rinse-off)
Optimal
0.0015% (maximum permitted in EU rinse-off)
EU: prohibited in leave-on; max 0.0015% rinse-off. KR: max 0.01% rinse-off only. US/JP: no specific limit but voluntary reformulation widespread.
Works Well With / Avoid
Works Well With
EU prohibits MIT in leave-on cosmetics (Regulation 2016/1198); max 0.0015% in rinse-off (CMIT/MIT blend) or 0.0015% MIT alone in rinse-off. Korea allows max 0.01% in rinse-off only. Canada banned in all cosmetics (2021).
Commonly Found In
Global Regulation Summary
Overview of current status across major international markets.
Detailed Regional Status
| Region | Status | Max Conc. | Conditions | Source |
|---|---|---|---|---|
| πͺπΊ EU | Allowed | - | - | Official β |
| πΊπΈ USA | Allowed | - | - | Official β |
| π―π΅ Japan | Allowed | - | - | Official β |
| π°π· Korea | Restricted | 0.01% | Only allowed in rinse-off products (prohibited in leave-on products) | Official β |
| π¬π§ UK | Banned | - | Follows EU regulations (V/57 V/39) | Official β |
π Why Regulations Differ
EU and UK ban MIT in leave-on products (SCCS/1521/13, 2014) and restrict to 0.0015% in rinse-off. Korea restricts to 0.01% rinse-off. Canada banned all cosmetic use (2021). Japan and US have not enacted similar bans, though widespread voluntary removal has occurred. Contact allergy epidemic data drove EU/UK action.
Recent Regulatory Changes
- β’ EU Regulation 2016/1198: Prohibited MIT in leave-on cosmetics (effective 2016)
- β’ Canada: Banned in all cosmetics (2021)
Regulation Analysis
Regional Agreement
Banned in UK but allowed in EU, USA, Japan.
Category Comparison
There are 157 ingredients in the PRESERVATIVE category. 99% are banned in at least one major market.
Strictness Ranking
πΏ Natural Sources
Synthetic only. Does not occur naturally.
π How It's Made
Synthesized through cyclization of N-methylthiourea with chloroacetyl chloride, followed by oxidation. Often produced alongside methylchloroisothiazolinone (CMIT) in commercial formulations.
π Uses in Cosmetics
Used at max 0.01% (100 ppm) in rinse-off products only in EU (since 2017). Banned in leave-on products in EU (2016, Regulation 2016/1198) due to high allergen rates. Effective against bacteria (both gram-positive and gram-negative), fungi, and algae. Designated as Contact Allergen of the Year 2013 by American Contact Dermatitis Society.
π¬ Other Applications
Used in industrial water treatment, paints, adhesives, metalworking fluids, and detergents. Also found in some household cleaning products.
π‘ Fun Facts
- β’ EU banned MIT in leave-on cosmetics in February 2016 after a sharp rise in contact allergy cases across Europe
- β’ Between 2007-2013, contact allergy to MIT increased from 1-2% to 6-10% in dermatology patients in European clinics
- β’ Canada banned MIT in all cosmetics in 2021, making it one of the strictest regulatory positions globally
Related Skin Concerns
Data Sources
- β’ SCCS/1521/13 (2014) β SCCS opinion on MIT
- β’ EU Regulation 2016/1198 β leave-on prohibition
- β’ American Contact Dermatitis Society (2013) β Contact Allergen of the Year
- β’ Uter W et al. (2015) β European contact allergy epidemic data
- β’ Health Canada (2021) β MIT ban in cosmetics
Last data verification: 2026-04-16
Related Ingredients
BENZETHONIUM CHLORIDE
BENZOIC ACID
BUTYLPARABEN
CETRIMONIUM BROMIDE
CETRIMONIUM CHLORIDE
CHLOROPHENE
Learn More
Frequently Asked Questions
What is METHYLISOTHIAZOLINONE used for in cosmetics?
METHYLISOTHIAZOLINONE is primarily used for preservative in cosmetic products. The ingredient is commonly found in various cosmetic products to prevent microbial growth.
Which countries regulate METHYLISOTHIAZOLINONE?
METHYLISOTHIAZOLINONE is banned in UK. It has concentration limits or usage restrictions in KR. The ingredient is freely allowed in EU, JP, US.
Are there alternatives to METHYLISOTHIAZOLINONE?
Due to regulatory restrictions on METHYLISOTHIAZOLINONE, cosmetic manufacturers often use alternative ingredients with similar functions. For preservative, alternatives may include other approved ingredients in the same category. Consult product labels for specific formulations, and look for products compliant with your region's regulations.
Where can I find official regulation information about METHYLISOTHIAZOLINONE?
Official information about METHYLISOTHIAZOLINONE regulations can be found on government websites: EU CosIng database, US FDA Cosmetics page, Japan MHLW cosmetics standards, UK Government cosmetics guidance, and Korea MFDS. Always verify regulatory status with these official sources before making formulation decisions.
Disclaimer
The information on this website is for educational and informational purposes only and is not intended as medical advice. While we strive for accuracy based on official government databases, cosmetic regulations change frequently. Always consult with a qualified professional or refer to the latest official regulatory documents for compliance. We are not responsible for any actions taken based on the information provided here.