Preservative · DMDM Hydantoin · CAS 6440-58-0

DMDM Hydantoin

This substance protects a product from bacteria by slowly releasing formaldehyde. The problem is exactly which preservative it releases in the process.

QDRO position

We avoid it

Avoided in QDRO. A formaldehyde donor: it gradually releases formaldehyde (an IARC Group 1 carcinogen) and is a contact allergen. We use mild preservative systems.

Any water-based product needs a preservative — otherwise it becomes a breeding ground for bacteria and mold. The question is not whether a preservative is needed, but which one. DMDM hydantoin is an example of a preservative whose cost outweighs its benefit.

How It Works

DMDM hydantoin belongs to the class of formaldehyde releasers. It is not formaldehyde itself, but in an aqueous environment it gradually releases it — and it is exactly the free formaldehyde that kills microorganisms. In other words, the preservative activity of the substance by definition means the presence of formaldehyde in the product.

The same group includes imidazolidinyl urea, diazolidinyl urea, and quaternium-15. The mechanism is common to all of them.

What the Problem Is

Formaldehyde is not a neutral substance. In 2012 IARC (the International Agency for Research on Cancer) confirmed its classification as a Group 1 carcinogen — proven for humans.

"There is sufficient evidence that formaldehyde causes nasopharyngeal cancer in humans."

— IARC Monographs, Vol. 100F

At the concentrations used in cosmetics, the concern is primarily about two effects: irritation and contact allergy. Formaldehyde releasers are among the most frequent causes of allergic contact dermatitis, and on contact with the oral mucosa this risk is especially undesirable.

Regulators are responding by tightening the rules. Since 2023 in the EU (Regulation 2022/1181), the threshold at which a product must carry a "releases formaldehyde" warning has been lowered to 0.001%. An additional backdrop is the wave of consumer lawsuits in the US over products containing DMDM hydantoin, which brought the topic into the mainstream.

What to Use Instead

Modern cosmetic chemistry has preservatives without a formaldehyde footprint: where needed — mild systems based on organic acids, phenoxyethanol in permitted concentrations, or formulations with low water activity that do not require an aggressive preservative.

QDRO selects preservative solutions on the principle of "as little as sufficient and without proven carcinogens in the chain." Formaldehyde releasers do not fit that principle — so there is no DMDM hydantoin in our products.