Ingredient

METHYLISOTHIAZOLINONE

Name / description

Methylisothiazolinone (MI, MIT), 2-Methyl-4-isothiazolin-3-one, 2-Methyl-2,3-dihydroisothiazol-3-one

Function(s) of this ingredient in cosmetic products

PRESERVATIVE

Protects cosmetic products from microbial spoilage

Origin

synthetic

Occurrence in cosmetics

Various rinse-off products, also in combination with methylchloroisothiazolinone or chloromethylisothiazolinone (CMIT / MCI)

Occurrence in other products

Paints, glues and cooling lubricants, household and industrial cleaning agents, stationery, lubricants, wood care and water treatment agents

Background information on use in cosmetics

Preservatives protect cosmetic products against microbial spoilage and hence make a major contribution to consumer health. Preservatives are particularly required in cosmetic formulations containing water, because microorganisms can colonise and reproduce in an aqueous (water-containing) environment. Cosmetics often contain more than one preservative substances and these preservative systems act simultaneously against different bacteria, yeasts or moulds. Each of these substances has been comprehensively tested and assessed for safety (individually and in combination). Manufacturers always use only the lowest possible effective concentration in a product so that an optimum shelf life and safe application are ensured.

Information on safe use

Methylisothiazolinone is used in cosmetic rinse-off products up to a concentration of 15 ppm as preservative. The European Scientific Committee for Consumer Safety (SCCS) assessed the use of methylisothiazolinone in rinse-off products in its opinion of December 2015 on the basis of extensive scientific data as safe. In accordance with the EC Cosmetics Regulation (Regulation (EC) No. 1223/2009), which applies to the entire EU market, preservatives means substances which are exclusively or mainly intended to inhibit the development of microorganisms in the cosmetic product. Annex V of the Regulation defines the substances which may be used as preservatives in cosmetic products. In this so-called positive list of preservatives, maximum concentrations are defined for the use of these substances in cosmetic products as well as the permissible uses. Preservatives are examined in respect of their toxicological safety prior to their approval in Annex V and undergo extensive tests. Manufacturers must prove the health safety in extensive scientific studies.

Why are we talking about it?

Methylisothiazolinone (MIT) and methylchloroisothiazolinone (MCIT) have a sensitising potential, i.e. they can induce an allergy. The facts: MIT and MCIT have been widely used as preservatives in cosmetic products to replace the unjustly criticised parabens. In view of the resurgence of skin allergy cases and the data confirming the sensitising potential of MIT and MCIT, cosmetics industry representative bodies at European level have recommended limiting their use since 2013 (1). In this context, the industry decided of its own accord to limit MIT use and alerted scientific experts on the grounds for this decision. MIT and MCIT are now banned in leave-on cosmetic products, and severely restricted in rinse-off products (much shorter contact time) (2, 3 and 4). The authorised concentration in rinse-off products is considered to be low enough to avoid inducing allergies in non-sensitised people (5). Key points to take away: Current restrictions on the use of MIT and MCIT allow for a safe use in rinse-off cosmetic products with regard to possible allergy induction in a non-allergic person. As with any ingredient in a cosmetic product, the presence of MIT and/or MCIT is indicated on the packaging. Thus, people who are already sensitised to MIT or MCIT can avoid using cosmetic products containing them. Sources: (1) https://cosmeticseurope.eu/files/3614/7634/5470/Recommendation_on_MIT.pdf (2) Cosmetic Products Regulation (EC) No 1223/2009; Annex V (3) European Scientific Committee on Consumer Safety (SCCS): SCCS/1521/13: https://ec.europa.eu/health/scientific_committees/consumer_safety/docs/sccs_o_145.pdf (4) European Scientific Committee on Consumer Safety (SCCS): SCCS/1557/15: https://ec.europa.eu/health/scientific_committees/consumer_safety/docs/sccs_o_178.pdf (5) Cosmetic Ingredient Review: Amended Safety Assessment of Methylisothiazolinone and Methylchloroisothiazolinone as Used in Cosmetics, 2021: https://pubmed.ncbi.nlm.nih.gov/34259066/

Further information

For the clarification of a suspicion of a contact allergy this substance can be routinely tested in the epicutaneous test at the dermatologist.

Belongs to the following substance groups

Preservatives

Regulating cosmetics

Cosmetics Ingredients are subject to regulation. Please note, different regulations may apply to cosmetic ingredients outside the EU.

Understanding your cosmetics

How are cosmetics kept safe in Europe?

Strict laws make sure that cosmetics and personal care products sold in the European Union are safe for people to use. Companies, national and European regulatory authorities share the responsibility of keeping cosmetic products safe.

What should I know about endocrine disruptors?

Some ingredients used in cosmetic products have been claimed to be ‘endocrine disruptors’ because they have the potential to mimic some of the properties of our hormones. Just because something has the potential to mimic a hormone does not mean it will disrupt our endocrine system. Many substances, including natural ones, mimic hormones but very few, and these are mostly potent medicines, have ever been shown to cause disruption of the endocrine system. The rigorous product safety assessments by qualified, scientific experts that companies are legally obliged to carry out cover all potential risks, including potential endocrine disruption.

Are cosmetics tested on animals? No!

In the European Union, testing cosmetics on animals has been fully banned since 2013. Over the last 30 years, long before a ban was in place, the cosmetics and personal care industry has invested in research and development to pioneer alternatives to animal testing tools to assess the safety of cosmetics ingredients and products.

What about allergens in cosmetics?

Many substances, natural or man-made, have the potential to cause an allergic reaction. An allergic reaction occurs when a person’s immune system reacts to substances that are harmless to most people. A substance that causes an allergic reaction is called an allergen. Cosmetics and personal care products may contain ingredients that can be allergenic for some people. This does not mean that the product is not safe for others to use.

Database

Cosmetics matter to people and play an important role in our everyday life. On average European consumers use over seven different cosmetics daily. You too? It’s only natural that you want to know more about the ingredients in those products.

In the digital world we live in, there’s a deluge of information on cosmetics. However, it can be difficult to know which sources are reliable. COSMILE Europe is a European cosmetic ingredient database that offers reliable, verified and scientifically supported information on almost 30,000 ingredients used in cosmetics.

This database will help you understand why certain ingredients are in your cosmetic products; which properties they have and much more. The database is currently available in fourteen languages with more to come.

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