Aesop are an apothecary-style luxury skincare blend, founded around 30 years ago in Australia, but available worldwide.

They offer cleansers, moisturisers, toners, masques, sun care, men’s products, hair care products, body gels and lotions, and others such as lip balms, deodorants, scents, oral care and more.

There have been a few discussions online about their policy on MI / MCI in the past, so I thought I’d write to them for a full position statement.

The response I received was quite long, so this is an edited response, focusing on the issue at hand:

Aesop does not use any Methylchloroisothiazolinone (MCI) and Methylisothiazolinone (MI) in any of our products designed to be left on the skin … Our products do not contain artificial fragrance, colourants, mineral oils, animal derivatives, pearlising agents and silicones, all of which may aggravate sensitive skin …


Preservatives such as these are a necessary and sensible part of all personal care formulations, their inclusion being crucial to the performance and longevity of the product. As a general note, as we use many botanical ingredients in our formulations, we include preservatives in doses as small as possible to ensure our products make it to your shelf in their most useful state … Our preference at Aesop is to minimise the need for preservatives by packaging in dark protective glass and anodized aluminium tubes (and thus minimising UV spoilage of product) and incorporating micro amounts of scientifically validated preservatives.


A number of Aesop rinse-off products contain a blend of MCI and MI well below the recommended limits set by regulatory agencies globally. These products are intended to be rinsed off the skin; therefore, the amount of time that the preservative is in contact with the skin is limited and the risk of skin sensitisation is very low.


Should you wish to explore rinse-off products without this blend, Parsley Seed Facial Cleansing Oil, Nurturing Shampoo, Geranium Leaf Body Scrub, Redemption Body Scrub do not contain this preservative blend.


We are currently in the process of reformulating Purifying Facial Exfoliant and our Cleansing Masques to remove this preservative blend due to the fact that, although rinsed-off, they do remain on the skin for a period of time.

I’ve looked at the ingredients of some products, and the MI / MCI blend is included in products you might expect — including some of their hair care products — but it’s a reassurance that leave-on products by Aesop are safe.

It’s also good to hear of Aesop’s plans to remove MI / MCI from leave-on/rinse-off products such as masques.

To learn more, see the Aesop Website, where all ingredients are provided. 


  1. Vee

    Thank you for the info.

  2. chris

    My allergy to MCI includes products that you rinse off (conditioner, shampoo, dish soap etc). The reason it took me 1 1/2 years to figure this out is because most allergies to this product do not occur until 48 hours afterwards so most people are thinking that it has to be something recent causing the reaction. This answer from the company means that you should just avoid any products that have MCI listed whether it is rinse off or not.

    1. MI Free (Post author)

      Irrespective of the answer from Aesop, you should avoid MI / MCI in all products if you are already sensitised, yes.


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