Imidazolidinyl Urea

Imidazolidinyl urea is a synthetic preservative that releases small amounts of formaldehyde in water-based formulations. It limits microbial growth and prolongs shelf life in lotions, shampoos, and other personal care products.
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Ingredient Snapshot

Overview
A preservative that keeps formulas fresh by fighting microbial growth.
Category
Preservative
Type
Preservative

Ingredient Ratings

Overall Rating

Fair

Comedogenic Risk

None

Skin Benefits

Helps keep formulas safe to use longer by discouraging microbial growth. Those with very reactive skin may prefer to patch test due to potential sensitivity.

Uses In Skincare & Cosmetics

Commonly included in water-based products such as moisturizers, cleansers, and shampoos to maintain product integrity during use.

Comedogenic Rating

This ingredient is not typically evaluated for comedogenicity, and no standardized rating is available.

Safety

Can cause irritation or allergic contact dermatitis, especially in individuals sensitive to formaldehyde; patch testing is prudent for reactive skin. Many regions cap free formaldehyde levels in finished products and require labeling above certain thresholds. Avoid use on compromised skin if sensitivity is known.

Is Imidazolidinyl Urea a Good Ingredient?

Rated Fair because it offers effective broad-spectrum preservation through slow formaldehyde release, but that benefit is balanced by a higher irritation and sensitization risk for sensitive skin and those with formaldehyde allergies. It works fine for low-cost, water-phase preservation, but many formulators reach for alternatives when reactive users are a concern, which keeps the rating in the middle.

Products with Imidazolidinyl Urea

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