Imidazolidinyl Urea.
Also known as: Germall 115, imidurea, N,N'-methylenebis(N'-(1-(hydroxymethyl)-2,5-dioxo-4-imidazolidinyl)urea)
A formaldehyde-releasing antimicrobial preservative used in cosmetics, pharmaceuticals, and personal care products. While less aggressive than quaternium-15, it still releases formaldehyde — a known human carcinogen — over time as it preserves the product.
By the numbers.
1 = low concern, 10 = avoid.
Risk by usage.
How risk shifts depending on how often you use products with Imidazolidinyl Urea.
Low-level formaldehyde exposure even from occasional use. Sensitized individuals should avoid entirely.
Daily use creates chronic low-level formaldehyde exposure. Avoid in leave-on products especially.
Significant carcinogen and allergen risk from cumulative formaldehyde exposure across products.
What the research says.
Releases formaldehyde, a known human carcinogen (IARC Group 1), slowly over the shelf life of the product.
IARC Monographs Volume 100F — Formaldehyde
Common contact allergen; ranked among the top cosmetic sensitizers in patch testing studies.
North American Contact Dermatitis Group — standard allergen series results
Can cause dermatitis, redness, and irritation, particularly in individuals already sensitized to formaldehyde.
Global status.
How imidazolidinyl urea is regulated in cosmetics around the world.
80% of countries with data ban or restrict this ingredient
Details
Max 0.6% as preservative (Annex V); must label 'contains formaldehyde' if >0.05%.
Details
Max 0.6% with labeling requirements.
Details
Restricted as formaldehyde releaser on Hotlist.
Details
Permitted under MHLW positive list with limits.
Details
Permitted with limits and formaldehyde labeling.
Details
Max 0.6% per Safety Technical Standards.
Details
Max 0.6% per ANVISA.
Details
Max 0.6%, aligned with EU.
The reason brands include it.
Effective antimicrobial preservative active against bacteria. Often used in combination with parabens or other preservatives for broader-spectrum protection.
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products in our database
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brands use it
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Better alternatives exist. Brands choose imidazolidinyl urea because it’s cheap and effective, but safer options like potassium sorbate, sodium benzoate, ethylhexylglycerin deliver similar results without the health concerns.
Imidazolidinyl Urea in product types.
Click a category to see every product containing imidazolidinyl urea.
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What to use instead.
What Numbrrrz uses instead
Numbrrrz is formaldehyde-free — always. Our lip balms are preserved naturally by Vitamin E, and our simple formula does not require synthetic antimicrobial preservation.