Ingredient Index

Is Methylisothiazolinone banned in Europe?

Restricted in EU

No, but nearly: the EU banned methylisothiazolinone from leave-on cosmetics in 2017 and caps it at 15 ppm in rinse-off products, while the US sets no binding limit.

CAS: 2682-20-4 Also seen as: MI, MIT

What the EU does

Restricted hard, after a self-inflicted epidemic. When paraben anxiety pushed formulators toward alternatives in the late 2000s, MI use exploded, and so did contact allergy, with European patch-test clinics recording sensitization rates above 10% at the peak, an outbreak dermatologists called unprecedented. The EU responded in stages: banned from leave-on products in 2017 (Regulation 2016/1198), then capped at 0.0015% (15 ppm) in rinse-off products (Regulation 2017/1224).

It stands as the EU's case study in preservative whack-a-mole: the replacement for the feared ingredient caused more documented harm than the original ever did.

Citation Regulation (EC) No 1223/2009, Annex V/57; Regulations (EU) 2016/1198 and 2017/1224

What the US does

Legal with no binding limit. The industry's CIR panel recommends MI only in rinse-off products and at concentrations the EU's rules roughly mirror, but CIR guidance is advisory: US leave-on products containing MI remain lawful, and some budget lotions and wipes still use it.

The American Contact Dermatitis Society named MI "Allergen of the Year" in 2013, and US sensitization data tracked the European outbreak. The market has substantially (not completely) self-corrected.

Citation FD&C Act general safety standard; CIR assessment of methylisothiazolinone

Products that commonly contain it

MI preserves water-based products. Watch for it in:

Shampoos, conditioners, and body washes (rinse-off; EU-legal at 15 ppm)
Baby wipes and moist towelettes (the leave-on use behind the outbreak; now rare)
Liquid laundry detergents and dish soaps (outside cosmetics rules entirely)
Budget US lotions (still legal; check labels if sensitized)
Wall paints, a genuinely common non-cosmetic sensitization source

What to look for on a label

For the sensitized, the names matter:

"Methylisothiazolinone" (MI) and "methylchloroisothiazolinone" (MCI), often paired as "MCI/MI" or trade name Kathon CG
EU leave-on products should never list MI; US leave-ons still can
"Benzisothiazolinone" (BIT) is the related preservative now appearing in its place; cross-reaction is possible

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Frequently asked questions

Is methylisothiazolinone banned in the EU?

In leave-on cosmetics, yes, since 2017. In rinse-off products it remains legal at up to 0.0015% (15 ppm). It is not fully banned.

Is methylisothiazolinone legal in the United States?

Yes, in any product type, with no binding concentration limit. Industry guidance recommends rinse-off-only use, and most major brands follow it.

Why did MI cause an allergy epidemic?

When brands fled parabens, MI use rose sharply, including in leave-on products and wipes, the highest-sensitization exposure. Patch-test positivity rates above 10% followed in European clinics, and regulators clamped down.

I'm allergic to MI. What should I check?

Ingredient lists for MI, MCI, and the Kathon CG pair; benzisothiazolinone as a possible cross-reactor; and non-cosmetic sources like dish soap, laundry liquid, and fresh wall paint, which are common and unlabeled exposures.

Related ingredients

Primary sources

Last reviewed June 10, 2026 · How we assign statuses