Methylchloriosothiazolinone ●
TL;DR. This ingredient is a synthetic preservative used to control bacteria, yeast, and mold in water-based personal care formulas. It is mainly associated with shampoos, body washes, and other rinse-off products.
What does Methylchloriosothiazolinone do in a cosmetic formula?
This ingredient is a synthetic preservative used to control bacteria, yeast, and mold in water-based personal care formulas. It is mainly associated with shampoos, body washes, and other rinse-off products.
Is Methylchloriosothiazolinone clean?
From a clean-beauty perspective, this ingredient is highly restricted because of its well-documented contact-sensitization profile. Many retailer standards exclude it, and EU rules limit it to rinse-off products at very low levels while prohibiting it in leave-on products.
Is Methylchloriosothiazolinone sustainable?
This material is synthetically produced, generally from petrochemical feedstocks, and is used at trace concentrations rather than as a renewable input. Its environmental profile is less aligned with low-impact formulation because it is biologically active and subject to tight concentration controls.
Is Methylchloriosothiazolinone COSMOS-approved?
This ingredient is not permitted under COSMOS-natural or COSMOS-organic standards. It has weak Green Chemistry alignment because it is synthetic, non-renewable, and selected for biocidal activity rather than benign degradation behavior.
How does Methylchloriosothiazolinone work chemically?
The molecule is a chlorinated, sulfur- and nitrogen-containing five-membered heterocycle that preserves formulas by disrupting microbial enzymes and cell metabolism. In the EU, it is allowed only in rinse-off cosmetics up to 0.0015% when used in its common preservative blend, and it is not allowed in leave-on cosmetics.
Last updated 2026-05-15