Methylisothiazolinone (methylisothiazolinone) in cosmetics. What is it, harm, what is it for, properties

A common chemical preservative found in cosmetics and personal hygiene products is methylisothiazolinone. By inhibiting the growth of mold and bacteria, it helps keep products safe to use and fresh for extended periods of time. It may be present in lotions, shampoos, conditioners, and even cosmetics.

Nevertheless, methylisothiazolinone has sparked worries about possible health hazards despite being widely used. Using products containing this ingredient may cause sensitivity, allergic reactions, or skin irritation in certain people. These responses have sparked conversations and increased awareness regarding its safety in cosmetics.

This article will discuss the functions of methylisothiazolinone, any potential negative effects, and the reasons behind its use in cosmetics. You can choose your skincare and haircare products more wisely if you are aware of their function and potential risks.

What is methylisothiazolinone

One member of the isothiazolinone group of contemporary preservative additives is methylisothiazolinone (MIT). An alternative to harmful formaldehydes and parabens—which are debatable from a safety perspective—was presented as isothiazolinones.

The substance dissolves easily in water, has a slight smell, and works well with:

• various types of surfactants (surfactants);
• proteins – basic components of any emulsions;
• emulsifiers.

Every member of the isothiazolinone family possesses the characteristic of being able to sustain their biocidal action, which eliminates detrimental microorganisms, at:

• temperature differences (including when heated to 60 degrees Celsius);
• change in acidity (pH values ​​from 2 to 9).

Methylchloroisothiazolinone (CMIT) is a related compound to methylisothiazolinone. Chlorine is a component of the halogenated preservative CMIT’s chemical formula. They are frequently combined; in the composition, MIT and CMIT are used.

Also, the following signs may point to the presence of MIT or CMIT in cosmetics:

• Kathon CG;
• Kordek;
• MCI / MCIT;
• Microcare MT;
• Neolone PE;
• Optiphen MIT;
• Rokonsal KS 4;

The action of methylisothiazolinone in cosmetics

Warning: Methylisothiazolinone is present in water-based cosmetics.

• mold;
• unpleasant odor;
• formation of toxins as a result of active microbial activity.

Water-based cosmetics must be stored, no matter how they are packaged.

If not, the following is greatly diminished:

• shelf life – even if the package is closed (some bacteria can multiply in the absence of air);
• shelf life after opening (indicated on the packaging by the icon "jar with open lid") – air access significantly "enriches" the composition of harmful microflora.

Three combined effects are produced by methylisothiazolinone, or MIT as it is commonly known in the cosmetics industry.

• bactericidal (fight against bacteria);
• fungicidal (prevention of the vital activity of fungal cells);
• algicidal (destruction of varieties of mold microalgae).

Because of the strong toxic activity of the MIT molecule, microorganisms are unable to respire inside their cells. It is advised that the substance be introduced into cosmetics at a percentage of between 0.1 and 2.5% because at 5% it is unquestionably unsafe. The actual numbers can be significantly lower for a number of brands, ranging from 0.002 to 0.004%.

What cosmetics contain

The European Association of Cosmetologists’ current guidelines state that methylisothiazolinone should only be utilized in rinse-off products.

Consequently, the component may be "legally" added to the following:

• cleansing milk/toner;
• toothpastes;
• mouthwashes;
• liquid soap, shower gels and foams;
• scrubs and peels;
• intimate hygiene products;
• hair shampoos and conditioners;
• nail polish removers.

In actuality, though, MIT is evident in the makeup of leave-in products:

• serums and creams;
• body lotions and milk;
• wet wipe impregnations;
• sunscreens;
• children"s cosmetics.

Simultaneously, mass-market brands (low price segment) actively use the component, such as:

• Yves Rocher;
• Nivea;
• Procter and Gamble.

The ingredients of L’Occitane, a product in the intermediate price range, include methylisothiazolinone.

A costly preservative (MIT is more costly than parabens) is also in demand from producers of high-end makeup:

• Giorgio Armani;
• Helena Rubinstein;
• Clarins;
• Sensai.

Russian companies whose owners employ MIT in their manufacturing include:

• Black Pearl;
• 100 Beauty Recipes;
• Nevskaya Cosmetics.

The ingredient is frequently found in the contents of goods marketed as "paraben-free," "ECO" or "BIO," made in Russia or elsewhere. However, the manufacturer’s bold claims are not supported by the existence of eco-certificates.

Safety of using methylisothiazolinone

The use of any preservative that is approved for use in cosmetics is theoretically justified because the risk of using cosmetics contaminated with microflora is significantly greater than the likelihood of the chemical compound causing harm. Since the 1970s, methylisothiazolinone has been a component of cosmetics.

Research at the time of component certification revealed that the following substance:

• has no teratogenic/mutagenic effect (does not cause disturbances or mutations during fetal development);
• is not a formaldehyde donor – does not decompose in cosmetics with the release of this toxic substance;
• well soluble in water – migration to the fatty phase with deterioration of the preservation quality is excluded;
• compatible with the components of the formulations;
• does not accumulate and does not pollute the environment (biodegradable).

In the USA, the component may be added to the composition in concentrations of up to 2.5%; usage in the EU and the Russian Federation is restricted in accordance with these regulations:

• EU 1223/2009;
• TR CU 009/2011.

The preservative is not allowed in leave-in products in Japan, and it is not permitted in children’s cosmetics in Germany. Numerous safety studies of the component have been carried out since 2002; the table presents the individual findings of these studies.

Year, country	Topic	Conclusions, comments
2002, USA, Brown University	Effect of low and slightly elevated concentrations on tadpoles	A slight excess of concentration leads to a delay in the development of the nervous system

There is evidence that the chemical can build up in the body and harm mature mammalian nerve cells. Several reports of allergic dermatitis exacerbations following product use enable us to discuss the compound’s immunotoxicity, or its capacity to harm the cells that control the immune system.

Additionally, the following information is included (in chronological order) and is based on research and statistical data:

1. The appeal of British doctors to cosmetics manufacturers with a request to remove methylizotiazolinonon and methyl chlorosotiazolinon from products (2013.).
2. Recognition of methylizotiazolinon "allergen of the year" according to the version of the American Society of Dermatitis (2013.).
3. Recommendations to refuse to use the component in leave-in cosmetics, in particular wet wipes – from the trade group "Cosmetics of Europe" and the "European Society of Contact Dermatitis" (2013).
4. Voluntary ban on the use of the ingredient in body creams from the "Committee of the European Commission on Consumer Safety". According to the commission, the rapid growth of contact reactions to isothiazolinones is associated with an increase in products containing these components. The presence and cause of allergies are confirmed by the results of applications of appropriate ties (2014).
5. Ban on adding to leave-in cosmetics in the European Union (2015).

Nearly 50 years ago, methylisothiazolinone first appeared in cosmetics. Prior to 2013, there was a noticeable rise in the number of allergy cases; however, as of right now, contact reactions are less frequent (perhaps as a result of new restrictions).

Consequences

In cosmetics, methylisothiazolinone is safe for people without hypersensitive skin as long as concentrations are monitored and the product is rinsed. The material does, however, have a high sensitization index of 9.

Cosmetic use can cause the following reactions in customers who are prone to allergies or contact dermatitis:

• itching;
• burning;
• small rash;
• skin damage up to burn-like ulcers – in rare cases;
• photostress contact dermatitis reactions – exacerbation of skin manifestations after sun exposure.

After using a cosmetic product regularly for several months, the reaction may happen right away or later.

Recommendations for choosing cosmetics

Experts predict that rather than a total prohibition on preservative use in the near future, there will likely be adjustments made to the acceptable concentrations. Additionally, producers are always looking for the best mixes of preservatives to lower toxicity and boost preservation system efficacy.

We can provide customers with the following advice in the interim.:

• refrain from buying children"s cosmetics/leave-on products containing methylisothiazolinone;
• when purchasing imported products, pay attention to the actual place of production (in the territory of the European Union, the USA, or the Russian Federation);
• if you have a tendency to dermatitis or photosensitivity, give preference to cosmetics with “green” preservatives that have certificates (Ecocert, Russian and European eco-certificates);
• avoid contact of products with methylisothiazolinone with the area around the eyes or mucous membranes of the organs of vision.

Compared to less expensive "light" products, professional luxury products’ methylisothiazolinone presence ought to raise fewer red flags.

There are two nuances to this:

• such cosmetics contain more active components. And the “more powerful” the product as a whole, the more effective the preservation system should be;
• respected brands protect their reputation and carefully control the content of preservatives, choosing low concentrations and/or safe combinations.

Alternative options

Experts say we shouldn’t anticipate the introduction of new preservatives to the market. You should be aware that every preservative has benefits, drawbacks, and usage nuances when selecting cosmetics.

The following summary is provided in the table:

• are natural preservatives;
• rarely causes irritation and dermatitis.

• irritation and allergic reactions are possible;
• can dry the skin and destroy the lipid layer of the skin.

• are found in plants and extracts, can be synthesized in the laboratory;
• do not affect the skin microflora;
• do not suppress the immune system;
• do not increase sensitivity to ultraviolet light.

• not effective enough against bacteria (antifungal activity is satisfactory);
• often require combination with other preservatives.

• effective in low concentrations;
• have high activity against bacteria;
• do not have a carcinogenic and mutagenic effect.

• increase sensitivity to sunlight;
• cause contact dermatitis;
• can accumulate in the environment.

• effective in low concentrations;
• low toxicity.

• can react with the components of the formulation to form carcinogens;
• may cause allergies and dermatitis.

• the preservative effect is provided by the auxiliary substances declared, such as, for example, fragrances.

• the inscription "without preservatives" creates the opinion among consumers that preservatives are always bad;
• cosmetics have a short shelf life

When "green" preservatives (those devoid of parabens, halogens, and aldehydes) are added, the manufacturer must:

• perfect production hygiene;
• high concentrations of preservative ingredients;
• use of premium-quality active components;
• special water treatment.

Because of the substantial price increases caused by all of these factors, you should exercise caution when purchasing inexpensive cosmetics that are labeled as "green."

A contemporary preservative that effectively increases the shelf life of cosmetics is methylisothiazolinone. As long as the concentrations are monitored and the substance is utilized in rinse-off products, it is safe. On the other hand, consumers who are hypersensitive or prone to dermatitis should avoid products containing methylisothiazolinone and instead choose "green" preservatives.

Topic	Details
What is methylisothiazolinone?	A preservative used in cosmetics to prevent bacteria and mold growth.
Harm	Can cause skin irritation, allergic reactions, and sensitivity, especially in high concentrations.
Why is it used?	It"s effective in extending the shelf life of products by preventing contamination.
Properties	Anti-bacterial, anti-fungal, and preservative.

A common preservative in cosmetics, methylisothiazolinone works to stop mold and dangerous bacteria from growing in the product. Due to its efficacy, it is frequently found as an ingredient in skincare and haircare products. But it’s critical to understand any possible hazards.

Methylisothiazolinone has been linked to allergies, skin irritation, and in some cases, even more severe reactions, according to studies. Those with sensitive skin or pre-existing conditions should be especially concerned. Because of this, a lot of manufacturers are beginning to use safer substitutes in its place and cutting back on its usage.

Choose cosmetics that use kinder preservatives if you’re worried about this ingredient and make sure to carefully read product labels. By doing this, you can lessen the possibility of irritation while maintaining the safety and efficacy of your products.

A common preservative used in cosmetics to stop bacteria from growing and increase shelf life is methylisothiazolinone. Though useful, it has been connected to allergic reactions and skin irritation, which raises questions about its safety in personal care products. Comprehending the intended use, possible risks, and characteristics of cosmetics can aid consumers in making well-informed selections.

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