Very Disliked
Methylisothiazolinone
Preservative
Preservative
May cause Irritation
These ingredients are considered potential irritants, meaning they can cause irritation - but not necessarily for everyone. Everyone’s skin is different, so what bothers one person’s skin may be completely fine for someone else.
Can worsen Eczema
These are common ingredients that may trigger eczema flare-ups, but everyone’s skin is different. If you have eczema or suspect you might, it’s important to check with a medical professional for the best care and product guidance.
Explained
MI is a preservative and known skin irritant. In the past, MI was used for its ability to prevent bacteria, yeast, and fungi growth in low doses.
Nowadays, you'll most likely see MI combined with Methylchloroisothiazolinone (MCI). Trade names for this combination include Kathon CG or Euxyl K 100.
Since then, numerous studies have shown this ingredient to cause contact dermatitis, or skin irritation.
The use of this ingredient varies around the world:
- The EU has banned this ingredient for leave-on products and it is capped at 0.0015% for rinse-off products.
- The US allows this ingredient in concentrations of up to 15 parts per million (ppm) in rinse-off products and 8 ppm in other products.
- Canada allows this ingredient to be used with MCI in rinse-off products. The combination must not exceed 0.0015%.
See all 992 products with Methylisothiazolinone
Users who like it
1%
Users who avoid it
99%
What it does
Preservative
Tending to preserve or capable of preserving.
Alternative names
Euxyl K 100
Mi
5-Chloro-2-Methyl-4-Isothiazolin-3-One
Mc/Mci-Cg
Mc/Mci-886
Kathon
5-Chloro-20methyl-3[H2]-Isothiazolinone
Prevalence
Uncommon
Percentage of products that contain it
1.1%
Top categories
Cleansers
Haircare
Treatments
Position
Predominant list placement
Bottom 25%
Concentration
Concentrations we've seen
1%
References
Products with Methylisothiazolinone
CosIng Data
CosIng ID
35341
INCI Name
METHYLISOTHIAZOLINONE
EC #
 220-239-6
All Functions
Preservative
