Ingredient

methylchloroisothiazolinone

High risk

FunctionPreservative

What it is

Methylchloroisothiazolinone (MCI) is a strong preservative, usually paired with methylisothiazolinone. It is effective at very low concentrations.

What it does

It protects products from bacteria, mould and yeast, keeping formulas safe and stable, particularly in rinse-off products.

Typical use

Found mainly in rinse-off products such as shampoos and cleansers; its use in leave-on products is restricted in the EU.

Who it suits / good to know

People with sensitive or allergy-prone skin often prefer to avoid isothiazolinone preservatives.

Safety

Graded high risk as a potent contact sensitiser. It is tightly regulated and can trigger allergic reactions, so it is best avoided by those prone to contact allergy. Patch-test any new product. This is general information, not medical advice.

Why we grade it High: High risk - isothiazolinone preservative and potent contact sensitizer.
Cross-reference

Found in these DHALIORA products

Found in 0 DHALIORA products

Not currently in any DHALIORA product.

How grades are set — Risk reflects our own reading of publicly available safety data, an EWG-style reading shown at the worst-case grade we've assigned this ingredient across products. It isn't a third party's proprietary score, and it isn't medical advice. Always read the packaging and patch-test where indicated.
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