TL;DR: Formaldehyde releasers — preservatives with names like DMDM hydantoin, quaternium-15, and imidazolidinyl urea — appear in many conventional baby shampoos and body washes. They work by slowly releasing small amounts of formaldehyde, a known human carcinogen, to prevent microbial growth. US regulators permit them; the EU restricts several of them in children’s products. Here’s what to look for on the label and why it matters for daily-use products applied to baby skin.
Why Does the Ingredient List on Your Baby’s Shampoo Actually Matter?
If you’ve ever flipped over a bottle of baby shampoo and run your finger down the ingredient list, you’ve probably scrolled past names like DMDM hydantoin or quaternium-15. They don’t sound alarming. They don’t sound like anything in particular. But they belong to a category of preservatives called formaldehyde releasers — and once you understand what they actually do, you won’t skip them again.
I started reading ingredient labels the same way most moms do: out of necessity. After learning that a product I trusted contained things I couldn’t explain, I made label-reading a habit. Formaldehyde releasers were something I kept running into — even in brands with words like “gentle” and “natural” on the front.
What Are Formaldehyde Releasers, and How Do They Actually Work?
Formaldehyde releasers are a class of preservatives that extend a product’s shelf life by slowly releasing small amounts of formaldehyde over time. The released formaldehyde prevents bacterial and fungal growth in the formula. They’re inexpensive, effective, and widely used — which is why they turn up in so many conventional shampoos, conditioners, lotions, and wipes, including products specifically marketed for babies.
The most common formaldehyde releasers you’ll find on ingredient labels include:
- DMDM hydantoin
- Quaternium-15
- Imidazolidinyl urea
- Diazolidinyl urea
- Bronopol (2-bromo-2-nitropropane-1,3-diol)
- Hydroxymethylglycinate
None of them say “formaldehyde” on the label. That’s the part worth knowing.
Why Does It Matter That Formaldehyde Is Being Released Into a Product?
Formaldehyde is classified as a Group 1 known human carcinogen by the International Agency for Research on Cancer (IARC) — meaning there is sufficient scientific evidence it causes cancer in humans. The National Cancer Institute has linked formaldehyde exposure to leukemia and nasopharyngeal cancer, primarily in occupational settings where concentrations are far higher than what’s present in a bottle of shampoo.
The standard industry position is that the amounts released by cosmetic preservatives are too small to pose a meaningful risk. For a single product used occasionally, that argument has some merit. But two things complicate that picture when we’re talking about babies specifically:
Cumulative daily exposure. Babies are often bathed every day with shampoo, body wash, lotion, and wipes — potentially several products at once, each containing a formaldehyde releaser. The National Institute of Environmental Health Sciences (NIEHS) notes that cumulative exposure from multiple low-level sources is a relevant factor when assessing total body burden, particularly for young children whose detoxification systems are still maturing.
Skin sensitization. Formaldehyde releasers are among the most frequently cited causes of preservative-related contact dermatitis in personal care products. Babies have thinner, more permeable skin than adults, which means ingredients absorb differently — and reactions, when they occur, can be harder to trace back to a specific ingredient buried in a daily-use product.
Are Formaldehyde Releasers Regulated Differently for Baby Products?
In the United States, the FDA does not require pre-market safety approval for cosmetic ingredients and has no specific prohibition on formaldehyde releasers in products designed for infants. The FDA has acknowledged the concerns around these ingredients but has not moved to restrict their use in baby products.
The European Union applies a stricter standard. Several formaldehyde-releasing preservatives are restricted or banned in EU cosmetics, and some are specifically prohibited in rinse-off products intended for children under three. That regulatory gap is real: a product sold legally in the US may not be permitted for use on young children in the EU. If you’ve ever used EU regulatory standards as a benchmark for ingredient safety, this is a meaningful difference to be aware of.
How Do You Actually Find These Ingredients on a Label?
They almost never appear as “formaldehyde” on an ingredient list — that’s exactly what makes them easy to miss. You have to recognize them by their individual names. Keep this short list somewhere accessible when you’re reading labels:
- DMDM hydantoin
- Quaternium-15 (one of the highest formaldehyde releasers in the category)
- Imidazolidinyl urea
- Diazolidinyl urea
- Bronopol
- Hydroxymethylglycinate
If you see any of these on a baby wash, shampoo, or lotion label, the product uses a formaldehyde-releasing preservative system. That’s the information you need to make the right call for your family.
What Does Kindred Naturals Use Instead?
Our baby shampoo and body wash was formulated from the start without formaldehyde releasers, synthetic fragrances, or ingredients we couldn’t explain out loud. We use soapwort as our plant-based surfactant — a gentle botanical cleanser that lathers without the harsh stripping of conventional surfactants — and we built the rest of the formula the same way: with ingredients we put on our own kids because we trust them.
Ingredient transparency isn’t a feature we added later. It’s the reason the brand exists.
Frequently Asked Questions
Is DMDM hydantoin safe for babies?
DMDM hydantoin works by slowly releasing formaldehyde to preserve a product’s shelf life. It’s permitted in US baby products but more tightly regulated in the EU. Given that baby skin is more permeable than adult skin and many families apply multiple products daily, many ingredient-conscious parents choose to avoid it. Effective preservation alternatives exist that don’t rely on formaldehyde release.
What is quaternium-15, and why does it show up in baby wash?
Quaternium-15 is a preservative that prevents bacterial growth in a formula by releasing formaldehyde — and it’s one of the strongest formaldehyde releasers in personal care products. It’s commonly found in mainstream baby shampoos and body washes and is also one of the leading preservative-related causes of contact dermatitis. Both facts are true at the same time, which is why it’s worth looking for on a label.
Are formaldehyde releasers banned in the US?
No. The FDA currently permits formaldehyde releasers in personal care products, including those marketed for babies, with no specific restrictions based on the child’s age. The EU applies stricter limits, particularly for products used on children under three. If you use EU standards as a safety benchmark, this is a meaningful gap to know about.
How do I know if my baby’s shampoo contains formaldehyde releasers?
Read the full ingredient list and look specifically for: DMDM hydantoin, quaternium-15, imidazolidinyl urea, diazolidinyl urea, bronopol, or hydroxymethylglycinate. Any of these names indicate the product uses a formaldehyde-releasing preservative. They will rarely appear under the word “formaldehyde” itself.
Are there effective preservatives for baby skincare that don’t release formaldehyde?
Yes. There are plant-derived and non-formaldehyde-releasing preservation systems that maintain product stability without relying on this mechanism. A brand that prioritizes transparency should be able to tell you what preservation system they use, how it works, and why they chose it. If they can’t, that’s worth noting.
If you want to see an ingredient list built on that standard, we’d love to show you ours at shopkindrednaturals.com.
Written by Mike & Carly Pronsky, founders of Kindred Naturals.