Ingredient guide
Methylchloroisothiazolinone (MCI) in Face Moisturizer
What Methylchloroisothiazolinone (MCI) does in face moisturizer and how it's regulated.
About Methylchloroisothiazolinone (MCI)
A potent synthetic biocide and preservative, almost always used in combination with methylisothiazolinone (MI) as the blend 'Kathon CG.
Why brands use it in face moisturizer
Extremely effective broad-spectrum preservative at very low concentrations. The MCI/MI blend (Kathon CG) is one of the most cost-effective preservation systems available.
Regulatory status
- US FDA: Still permitted in US cosmetics at any concentration. No restrictions despite being banned in EU leave-on cosmetics and heavily restricted in rinse-off products.
- European Union: Not permitted in cosmetics
- Canada: Restricted in cosmetics
Common alternatives
Other ingredients formulators use for a similar job in face moisturizer:
potassium sorbate
sodium benzoate
ethylhexylglycerin
tocopherol (vitamin E)
rosemary extract
FAQ
What is Methylchloroisothiazolinone (MCI)?
A potent synthetic biocide and preservative, almost always used in combination with methylisothiazolinone (MI) as the blend 'Kathon CG.
Why is Methylchloroisothiazolinone (MCI) used in face moisturizer?
Extremely effective broad-spectrum preservative at very low concentrations. The MCI/MI blend (Kathon CG) is one of the most cost-effective preservation systems available.
How is Methylchloroisothiazolinone (MCI) regulated?
Still permitted in US cosmetics at any concentration. No restrictions despite being banned in EU leave-on cosmetics and heavily restricted in rinse-off products. It is not permitted in cosmetics sold in the EU. Canada restricts its use in cosmetics.
Does Numbrrrz lip balm contain Methylchloroisothiazolinone (MCI)?
No. Numbrrrz is organic coconut oil, organic beeswax, organic jojoba oil and vitamin E, plus organic essential oils or flavoring in the scented versions. That is a formulation choice, not a judgment about other products.
