Ingredient decoder

Methylisothiazolinone: is it comedogenic? What it does in skincare

INCI name: Methylisothiazolinone

Acne verdict Watch

Worth watching on acne-prone skin

  • ComedogenicNo published rating
  • IrritancyNo published rating

What it does

Strong preservative and a common contact allergen.

  • Preservative

Methylisothiazolinone in plain English

Methylisothiazolinone is a strong preservative used in very small amounts, mostly in rinse-off products like shampoos and washes. It became one of the most common causes of contact allergy, so the EU no longer allows it in leave-on cosmetics and caps it in rinse-off products. It does not clog pores, but if your skin reacts easily it is a good one to avoid.

Is methylisothiazolinone bad for acne?

Not usually, but it is worth watching. Methylisothiazolinone is not a proven pore-clogger, but this preservative family is a well-known cause of skin allergies and irritation. Notice how your skin reacts when a product lists it near the top.

Clean routine and still breaking out? The cause may be internal. See what is driving it

Also called

  • Methylisothiazolinone
  • MIT
  • 2-methyl-4-isothiazolin-3-one
  • Methylisothiazolone

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Frequently asked questions

Is methylisothiazolinone comedogenic?

Methylisothiazolinone has no published comedogenic rating in Fulton's 1989 table. It is not a proven pore-clogger, but it is worth watching on acne-prone skin.

What does methylisothiazolinone do in skincare?

In short: strong preservative and a common contact allergen. In formulas it is used for preservative.

What else is methylisothiazolinone called on ingredient labels?

On ingredient lists, methylisothiazolinone can also appear as MIT, 2-methyl-4-isothiazolin-3-one or Methylisothiazolone.

Sources