Preservative from the formaldehyde-releaser group: gradually releases trace amounts of formaldehyde. A portion of people reacts with contact allergy.
Topical application
DVery weak or conflicting data.
Patch tests find formaldehyde sensitization in 2–5% of people with contact eczema. Modern formulas increasingly switch to alternative preservatives without free formaldehyde.
Imidazolidinyl Urea is a preservative from the formaldehyde-releaser group. In aqueous environment it slowly releases trace formaldehyde (10-50 ppm) that inhibits bacterial and fungal growth. Used since the 1960s. Where applied. Shampoos, conditioners, creams, lotions, soaps, micellar waters (0.1-0.6%). In Spain – Garnier, L'Oréal Paris, Babaria, Pantene. EU permits up to 0.6% (Regulation 1223/2009 Annex V). Often in blend with propylene-/diazolidinyl urea to broaden antimicrobial coverage. Allergy. Imidazolidinyl urea is among the top ten most frequent contact allergens in cosmetics. IVDK data: sensitization in 1.5-2.5% of dermatitis patients. More often patients react not to the substance itself but to released formaldehyde. ESCD keeps it in the standard patch-test panel. Safety. CIR rated imidazolidinyl urea safe at cosmetic concentrations up to 0.6% (1980, re-evaluated 2017). EU SCCS confirmed safety. Formaldehyde itself has been banned as a cosmetic preservative in the EU since 2014, but formaldehyde-releasers are allowed with package labeling ("released formaldehyde from preservatives"). Pregnancy – topical use at cosmetic concentrations is acceptable, no direct teratogenicity data. Lactation – no specific restrictions, minimal risk. Alternatives: phenoxyethanol, benzyl alcohol, sorbic acid – in patients with confirmed formaldehyde-releaser allergy. This is a formaldehyde-releasing preservative: in the water phase it slowly gives off small amounts of free formaldehyde. If you are allergic to formaldehyde or have very sensitive skin, choose a product without it – at permitted levels the risk for everyone else is low. When several such preservatives are combined, their formaldehyde adds up, and in the EU a total above 0.001% requires a "releases formaldehyde" label. It often appears next to parabens on the label – that is not a reaction between them but a ready-made preservative blend (e.g. Germaben): the urea releases formaldehyde, parabens have nothing to do with it.
Irritation potential
MediumAllergen risk
HighPregnancy
CautionReleases formaldehyde
This is a formaldehyde-releasing preservative: it slowly gives off small amounts of formaldehyde in the water phase. If you are allergic to formaldehyde or have very sensitive skin, choose a product without it. At permitted levels the risk for everyone else is low. When several such preservatives are combined, their formaldehyde adds up – that matters more than any single one.
Use with caution
The Evigrade extension adds an evidence panel to iHerb, Sephora, Druni and 12 more stores. This ingredient and every other one in the product show evidence-tier, allergen risk and pregnancy/lactation flags at a glance.
Imidazolidinyl Urea should be used with caution during pregnancy. Consulting a dermatologist or OB-GYN is advisable.
Use with caution in: sensitive.
Imidazolidinyl Urea has moderate irritation potential. Sensitive skin may show a transient reaction that usually settles with adaptation.
Imidazolidinyl Urea has high allergen potential. Perform a patch test on the inner forearm 24 hours before facial application.
Preservative from the formaldehyde-releaser group: gradually releases trace amounts of formaldehyde.
The INCI name is Imidazolidinyl Urea.
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