Ingredient
MIT
MIT is flagged for general use, pregnancy, breastfeeding, postpartum, trying to conceive and PCOS. The concern behind the strongest flag is common allergen and irritant.
- Methylisothiazolinone
- 2-Methyl-4-isothiazolin-3-one
- MI
Verdict by profile
Truva checks every ingredient against six profiles. Jump to any of them for the full assessment.
- Strongest verdict
- Not Recommended
- Its verdict for general use, the profile this one is worst in
- Profiles flagged
- 6 of 6
- Counting avoid, high risk and medium risk
- Irritancy
- 4 of 5
- Higher means more likely to sting or redden
MIT and pregnancy
Caution Advised
- Common allergen
- Irritant
Methylisothiazolinone (MIT) is a preservative used to prevent microbial contamination in cosmetic products. While it's effective at preventing bacterial growth, it has gained notoriety as one of the most common causes of cosmetic-related allergic contact dermatitis. There are no specific studies indicating MIT causes harm to fetal development, and it's not classified as a teratogen. However, pregnancy can make skin more sensitive and reactive due to hormonal changes. The high rate of sensitization and allergic reactions associated with MIT makes it less suitable during pregnancy when skin sensitivity is often heightened. Allergic reactions during pregnancy can cause significant discomfort and may require treatment that could be more complicated during pregnancy. While regulatory bodies have not specifically prohibited MIT use during pregnancy, the EU has banned it from leave-on cosmetic products for the general population due to sensitization concerns. Many dermatologists recommend pregnant women avoid potential allergens like MIT, especially in leave-on products, to minimize the risk of developing contact dermatitis when treatment options may be limited.
MIT and breastfeeding
Caution Advised
- Common allergen
- Irritant
MIT is a preservative with well-documented sensitizing properties. While there is minimal systemic absorption from topical application, making transfer to breast milk unlikely, the primary concern during breastfeeding relates to its allergenic potential and skin irritation. If MIT products are applied near the breast area, there's a risk of direct infant contact with the preserved product or with skin experiencing an allergic reaction. Allergic contact dermatitis on the chest area could make breastfeeding uncomfortable and potentially expose the infant to irritated skin or residue from the product. The SCCS notes that MIT is a potent sensitizer that can cause reactions even at low concentrations. Dermatologists generally recommend breastfeeding mothers avoid known strong allergens like MIT, particularly in products used on the chest, hands, or face where infant contact is likely. Many physicians suggest choosing products with gentler preservatives during the breastfeeding period to minimize the risk of developing sensitization or exposing the infant to potential irritants.
MIT and postpartum
Caution Advised
- Common allergen
- Irritant
For postpartum women not breastfeeding, the concerns with MIT are the same as for the general population: primarily its high potential for causing allergic contact dermatitis. Postpartum hormonal changes may make skin more reactive and sensitive. While there are no specific postpartum contraindications beyond the general sensitization risk, many women prefer to avoid potent allergens during the postpartum period when skin may already be dealing with hormonal changes and increased sensitivity. Consider choosing products with gentler, less allergenic preservatives.
MIT and trying to conceive
Caution Advised
- Common allergen
- Irritant
MIT is a preservative with well-documented allergenic properties but no known effects on fertility or reproductive health. It does not interfere with conception or hormone balance based on current evidence. However, since women trying to conceive should consider avoiding substances they'll need to discontinue during pregnancy, and given MIT's high sensitization rate, it may be prudent to choose products with gentler preservatives. This allows you to establish a skincare routine that can safely continue through conception and pregnancy. Additionally, developing a new allergic sensitization to MIT while trying to conceive could complicate your skincare options once pregnant.
MIT and PCOS
Caution Advised
- Common allergen
- Irritant
- Can inflame skin
MIT is a preservative with no direct hormonal effects, meaning it doesn't interact with androgens or affect the endocrine system. However, its strong allergenic and irritant properties are relevant for women with PCOS. Women with PCOS often have more sensitive or acne-prone skin due to hormonal factors. Introducing a potent allergen and irritant like MIT may exacerbate skin inflammation or trigger reactions that could worsen acne or other PCOS-related skin concerns. Inflammatory responses from allergic reactions could potentially aggravate existing skin issues. While MIT doesn't directly affect PCOS or hormone balance, dermatologists often recommend women with PCOS-related skin sensitivity choose gentler, less irritating preservatives. The EU ban on MIT in leave-on products reflects widespread concern about its sensitizing potential across all populations.
MIT and general use
Not Recommended
- Common allergen
- Irritant
MIT is one of the most common causes of allergic contact dermatitis from cosmetics. The American Contact Dermatitis Society named it the Contact Allergen of the Year in 2013 due to epidemic rates of sensitization. It can cause reactions ranging from mild redness and itching to severe blistering and eczema. According to the SCCS, the rate of MIT sensitization has increased dramatically since it began replacing parabens in cosmetics. Once sensitized, individuals must avoid MIT for life as reactions typically worsen with repeated exposure. The preservative is particularly problematic in leave-on products where prolonged skin contact increases sensitization risk. The EU banned MIT from leave-on cosmetic products in 2017 and restricted its concentration in rinse-off products to 0.0015%. Many dermatological societies, including the American Academy of Dermatology, recommend avoiding MIT-preserved cosmetics, especially for individuals with sensitive skin or a history of contact dermatitis. Numerous countries have followed the EU's lead in restricting this ingredient.
Everything else flagged for the same profiles
Related ingredients
Ingredients suggested in place of MIT, each one with its own page here.
Ingredients that raise the same concerns.
Where this came from
Truva summarises published guidance from bodies including ACOG, the FDA, the EU SCCS and the Cosmetic Ingredient Review. It has no access to your medical history and it is not a substitute for your doctor, dermatologist or midwife. These assessments have not been reviewed by a clinician, and nothing here is a diagnosis or a prescription. If you are pregnant, breastfeeding or being treated for PCOS, take the ingredient list to the person looking after you.
Assessment last pulled from the ingredient database on .
One ingredient is the easy case.
A label has thirty of them. Truva reads the whole list at once and answers for the profile you set: pregnancy, breastfeeding, postpartum, trying to conceive, PCOS, or general use.
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