Take the Quiz - Get 15% OFF your 1st Order
Search

Chapter 6: Preservatives

Methylisothiazolinone (MIT)

  • Poison schedule (Australia)
  • Officially classed skin allergen
Also called
MI, methylisothiazolone
Found in
dishwashing liquid, laundry liquid, sprays, paint

The worst fact: MIT allergy hit "epidemic proportions" in some European countries, even showing up in toddlers. In one Croatian clinic study, dishwashing liquid and laundry detergent were the most common culprits. In Australia it's a Schedule 6 Poison above 0.1% in a household product not meant to go on skin (1 part in 1,000), and above 0.0015% in a rinse-off cosmetic like shampoo. That's 15 parts per million, about one drop in a 3-litre bucket.

Why brands use it: it's used at tiny levels: 2 to 100 parts per million in cosmetics, and up to about 300 in some paints, so a drop goes a long way.

Take care if: you have eczema or are already allergic to it. Household labels don't always list it.

Comes from: made in a lab. It's fully synthetic.

Myth check: "a tiny amount can't cause allergy": it can. Many allergic people reacted at 0.005% (50 parts per million), half the cosmetic limit at the time.

Contaminants: nil.

Fair to say: most people never react. The EU now allows it only in rinse-off cosmetics, at no more than 0.0015%.

Correct as of November 2026. What the badges mean

Sources

  • Australian Government. Poisons Standard October 2026 (SUSMP), F2026L01327. Entries: methylisothiazolinone, methylchloroisothiazolinone, 2-phenoxyethanol, benzalkonium chloride. legislation.gov.au
  • Safe Work Australia. Hazardous Chemical Information System (HCIS): classifications for each chemical and for benzene, ethylene oxide, toluene, phenol and benzyl chloride. hcis.safeworkaustralia.gov.au
  • Scientific Committee on Consumer Safety (SCCS). Opinions on methylisothiazolinone (SCCS/1557/15), benzisothiazolinone (SCCS/1482/12) and phenoxyethanol (SCCS/1575/16). health.ec.europa.eu
  • Ljubojević Hadžavdić S et al. Methylisothiazolinone contact allergy in Croatia. Contact Dermatitis 2018;79:162-167.
  • Lundov MD et al. Methylisothiazolinone contact allergy. Br J Dermatol 2011. doi:10.1111/j.1365-2133.2011.10523.x

The full source list is at the end of Chapter 6.