Do Aesop products contain the preservatives Methylchloroisothiazolinone (MCIT) and Methylisothiazolinone (MIT)?

Methylchloroisothiazolinone (MCIT) and Methylisothiazolinone (MIT) are two commonly used preservatives for personal care products, conferring anti-microbial benefits by preventing the growth and reproduction of micro-organisms. MCIT and MIT are considered effective preservatives because they can be used at very low concentrations and are stable in even the most difficult to preserve formulations. Under stringent current cosmetic regulations, both ingredients continue to be recommended as safe for use in rinse-off products.

Aesop does not use MIT or MCIT in any product designed to be left on the skin. A number of our rinse-off products contain a blend of both ingredients, at levels well below the recommended limits set by regulatory agencies globally. If these products are used as directed, the preservative is in contact with the skin only for a limited time and the risk of skin sensitisation is therefore very low.


Regarding ongoing usage, we would emphasis that we consistently undertake systematic reviews of all existing products to ensure that our formulas are always as safe, robust and effective as possible. 

We have recently reformulated a number of products to replace MCIT/MIT with another preservative system. Further, we are in the process of reformulating all Aesop cleansing products, with a number having been completed; while this is primarily focused on improving formula robustness, the reformulations will include replacement of both MCIT and MIT.

Our decision to reformulate our products has not been made lightly. The process is challenging for any product, and particularly complex when working with preservative systems. However, we believe there is an opportunity to improve the performance and quality of our products by replacing MIT and MCIT, and to this end a number of products have undergone reformulation to remove these preservatives.

Subject to any unforeseen delays, reformulations for any remaining cleansing products are expected to be available from late 2020. Subsequent to this, no Aesop formulation will contain MCIT or MIT.

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