EWG Risk Score:
What is it?
Methylisothiazolinone is a synthetic cosmetic preservative.
Why is it a risk?
- Methylisothiazolinone is a known neurotoxin. In 2004, the European Scientific Committee on Cosmetic Products and Non-Food Products Intended for Consumers (SCCNFP) suggested that companies limit the maximum concentration to 0.01% (100 ppm). However, US companies are not required to follow this guideline.
- It is known to be absorbed through skin. A study at the Pittsburgh School of Medicine concluded that "Prolonged exposure to low levels of MIT and related compounds may have damaging consequences to the developing nervous system."
- Is a developmental toxin. (Source)
- Is a known contact allergen. (Source)
Although concentrations of this ingredient are typically very low in a formulation, I personally suggest avoiding this ingredient.