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Diazolidinyl Urea

What-it-does: preservative

Official CosIng Information


An antimicrobial preservative that helps your products not to go wrong too quickly. It works especially well against bacteria, specifically gram-negative species, yeast, and mold.

Somewhat controversial, it belongs to an infamous family of formaldehyde-releasers. That is, it slowly breaks down to form formaldehyde when it is added to a formula. We have written more about formaldehyde-releasing preservatives and the concerns around them at Dmdm Hydantoin, but do not get too scared, those are more theories than proven facts.

As for Diazolidinyl Urea itself, a study from 1990 writes that at concentrations up to 0.4%, it was a mild cumulative skin irritant, but the CIR (Cosmetic Ingredient Review) reviewed it in 2006 and found that, in concentrations of <0.5%, it is safe as used, as the amount of formaldehyde released will be smaller than the recommended limit (of less than 0.2%).

All in all, it is up to your personal decision and skin sensitivity. 

Show me some proof

  • Liebert, M. A. "Final report on the safety assessment of diazolidinyl urea." J. Am. Coll. Toxicol 9 (1990): 229-245.

Products with Diazolidinyl Urea

Thursday Plantation Aloe Vera Gel iNova Pharmaceuticals ReTrieve Cream with Tretinoin Idraet Serum Hialuronico Monu Gentle Toner Monu Rosewood Reviving Mist Needs Face Água Micelar OXY Emergency Wash PROSACEA Medicated Rosacea Gel SunSense Anti-Ageing Face Spf 50+ Sunscreen Urisec 22% Urea Cream CULLUN Tropical Bio-Toning Essence Derma V10 Stimulating Eye Roll On With Caffeine DermaVix Anti Aging Formula HydroSkinCare Ha² Serum Monu Clarifying Toner Cathy Doll Toner Essence Caviahue Serum C Idraet Vitamin C Night Serum JAN MARINI Skin Zyme Face Mask Kaya Purifying Toner Mario Badescu Hair Rinsing Conditioner Uremol 10 Urea 10% Skin Relief Moisturizing Lotion Treatment (2.5% Benzoyl Peroxide) Adasept Antibacterial Face & Body Skin Cleanser Elemis Pro-Collagen Advanced Eye Treatment Fruit of the Earth Aloe Vera 100% Fruit of the Earth Aloe Vera Gel Jessicurl Aquavescent Hair Spray KitosCell Gel Monu Active Toner Needs Face Sabonete Gel OXY Rapid Treatment Face Wash Portia M Pomegranate Toner TianDe Phyto Code Cleanser Ziaja Pro Neutralizator baby bright Lemon & Vit C Whitening Dark Spot Roller Serum elevegan Tónico Facial Para Todo Tipo De Piel Dormer 211 Hyperemollient Cream Idraet Hyaluronic Serum Jessicurl Spiralicious Gel Mario Badescu Glycolic Acid Toner OXY Sensitive Face Wash Ofra Foaming Vitamin C Cleanser Real Chemistry Daily Serum Real Chemistry Luminous 3-Minute Peel Skin Cleaner Gel Hidratante Somme Institute Boost Warming Mask pHisoderm Ph Clinical For Blemish-Prone Skin Alpha Skin Care Essential Renewal Gel With 10% Aha Balay Aloe Vera 99% Soothting Gel