TL;DR: Methylisothiazolinone (MIT), often paired with methylchloroisothiazolinone (CMIT), is a preservative found in some baby washes, shampoos, and especially wet wipes. It was named "Allergen of the Year" in 2013 after contact allergy rates spiked, and the EU has since restricted or banned it in leave-on products because no safe concentration could be established for allergy risk. It's still permitted in the U.S. at low levels, so the only reliable way to know if it's in your baby's products is to read the ingredient label. Kindred Naturals' Baby Shampoo & Body Wash is formulated without MIT or CMIT, using soapwort as our plant-based cleanser instead.
You've probably scanned a "gentle" or "hypoallergenic" label, felt reassured, and moved on. That's exactly the problem. Those words aren't regulated, and a preservative with a documented allergy track record can sit quietly in the ingredient list of a product marketed as safe for sensitive skin. If your baby has ever developed an unexplained rash after a bath or a fresh pack of wipes, methylisothiazolinone is worth knowing about.
What Is Methylisothiazolinone, and Why Is It in Baby Products?
Methylisothiazolinone (MIT) is a synthetic preservative used to prevent bacteria and mold from growing in water-based products. It's often combined with a related compound, methylchloroisothiazolinone (CMIT), and the pairing shows up on labels as "methylchloroisothiazolinone (and) methylisothiazolinone." You'll find it in baby shampoos, body washes, wipes, and lotions because it's inexpensive and effective at keeping products shelf-stable.
The catch is that effectiveness against bacteria doesn't mean it's gentle on skin. MIT and CMIT are recognized skin sensitizers, meaning repeated exposure can train the immune system to react to them, sometimes after months or years of a product seeming fine.
Why Did Methylisothiazolinone Become "Allergen of the Year"?
In 2013, the American Contact Dermatitis Society named methylisothiazolinone its Allergen of the Year, a designation given when a single ingredient causes a sharp, well-documented rise in contact allergy cases. Dermatologists across the U.S. and Europe reported a wave of allergic contact dermatitis, itchy, red, sometimes blistering rashes, traced back to MIT in everyday personal care products.
That surge pushed European regulators to take a closer look. The EU's Scientific Committee on Consumer Safety concluded that MIT is only acceptable in rinse-off products, like shampoo or body wash, and only at a maximum of 15 parts per million (0.0015%). For leave-on products such as lotions and moisturizers, the committee found no concentration low enough to rule out allergy risk, and the EU banned MIT from leave-on cosmetics entirely.
Is It Regulated the Same Way in the U.S.?
Not quite. The U.S. hasn't adopted the same restrictions, which means MIT and CMIT can still legally appear in rinse-off and some leave-on products sold here, including items marketed for babies. That gap is a big part of why label reading matters more than trusting a "gentle" claim on the front of the bottle.
Is Methylisothiazolinone More Concerning in Wipes Than in Wash?
Yes, and the reason comes down to contact time and skin barrier. Wet wipes involve direct, repeated rubbing against skin, often on the diaper area, where the skin barrier is already more permeable and prone to irritation. Regulatory reviewers have specifically flagged wipes as a higher-risk category, noting that MIT would need to be kept below 100 parts per million in wipe-type products to have any chance of being considered safe, well below what's typically used in rinse-off products like body wash.
A quick rinse-off bath product that's fully washed away is a different exposure than a wipe left in contact with skin for a moment during a diaper change, repeated many times a day, every day.
How Can You Tell If a Product Contains MIT?
Check the ingredient list for any of these names, sometimes listed together, sometimes alone:
Methylisothiazolinone, MIT, or MI. Methylchloroisothiazolinone, CMIT, or MCI. The combined listing "methylchloroisothiazolinone (and) methylisothiazolinone," often abbreviated as CMIT/MIT or MCI/MI.
If you see any of these on a baby wash, shampoo, or wipe label, especially paired together, that product carries the sensitization risk described above, regardless of what the front label promises.
What Does Kindred Naturals Use Instead?
Our Baby Shampoo & Body Wash doesn't use MIT or CMIT. We built the formula around soapwort, a plant-based cleanser, along with a preservation approach chosen for gentleness rather than the cheapest shelf-stable option. Every ingredient is listed plainly on our packaging and at shopkindrednaturals.com, so you can check for yourself rather than taking our word for it.
Frequently Asked Questions
Is methylisothiazolinone banned in the United States?
No. The EU has restricted MIT to low levels in rinse-off products and banned it from leave-on products, but the U.S. has not adopted equivalent restrictions. MIT and CMIT remain legal in many personal care products sold domestically.
What does an MIT allergy look like on a baby's skin?
Typically a red, itchy rash, sometimes with small blisters, appearing where the product made contact, often the diaper area with wipes, or the body with wash and shampoo. It can develop even after months of using a product without a reaction, since sensitization builds over repeated exposure.
Are "hypoallergenic" baby products free of MIT?
Not necessarily. "Hypoallergenic" isn't a regulated or standardized term in the U.S., so a product can carry that label and still contain MIT or CMIT. Reading the actual ingredient list is the only reliable way to know.
Is CMIT more concerning than MIT alone?
Research suggests dermal irritation is more common in products containing CMIT or CMIT/MIT combinations than in products with MIT alone, which is part of why the European Society of Contact Dermatitis has recommended against CMIT in leave-on skin products specifically.
What should I look for instead of MIT-preserved products?
Look for a full, transparent ingredient list rather than marketing terms, and check for plant-based preservation systems or brands that name their preservative approach openly rather than hiding behind "preservative blend."
Reading past the front-of-bottle claims can feel like one more job on an already full plate, but you don't need a chemistry degree to do it, just a habit of flipping the bottle over. If you're ready to simplify that search, our Baby Shampoo & Body Wash is formulated without MIT or CMIT and every ingredient is listed in plain language at shopkindrednaturals.com.
Written by Mike & Carly Pronsky, founders of Kindred Naturals.