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Diazolidinyl Urea

What-it-does: preservative


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 Monu Gentle Toner Monu Rosewood Reviving Mist PROSACEA Medicated Rosacea Gel Urisec 22% Urea Cream CULLUN Tropical Bio-Toning Essence Derma V10 Stimulating Eye Roll On With Caffeine HydroSkinCare Ha² Serum Monu Clarifying Toner Mario Badescu Hair Rinsing Conditioner Treatment (2.5% Benzoyl Peroxide) Elemis Pro-Collagen Advanced Eye Treatment Fruit of the Earth Aloe Vera 100% Fruit of the Earth Aloe Vera Gel Monu Active Toner baby bright Lemon & Vit C Whitening Dark Spot Roller Serum Mario Badescu Glycolic Acid Toner OXY Sensitive Face Wash Real Chemistry Daily Serum Real Chemistry Luminous 3-Minute Peel Balay Aloe Vera 99% Soothting Gel Elemis Absolute Eye Serum La Tulipe Acne Care Serum PH Advantage One Step Cleanser Beautifully Scrumptious Body Butter Aloe Vera Erno Laszlo Hydraphel Skin Supplement Hydrating Toner Freeman beauty Detoxifying Charcoal + Black Sugar Löwengrip Eyelighter Eye Cream SunSense Daily Face Spf 50+ This Works Deep Sleep Pillow Spray evagloss Lightening Serum Jamieson Provitamina Moisture Rich Vitamin E Moisturizing Cream Marcelle Flawless Foundation Monu Firming Moisturiser Monu Revitalising Moisturiser Nanowhite Fresh Mattifying Moisturiser Neutrogena Sheer Oil-Lotion Light Sesame Formula Skin Actives T-Zone Serum Ziaja Manuka Tree Face Toner Alpha Skin Care Intensive Renewal Serum, 14% Glycolic Aha DrGL Cleanser Lightening DrGL Skin Repair Elemis Pro-Collagen Eye Renewal Holy Snails Shark Sauce Invisible Zinc Environmental Skin Protector Spf30+ Mario Badescu Vitamin E Night Cream Nip+fab body Cellulite Fix O’Keeffe’s Working Hands Hand Cream Purpose Dual Treatment Moisture Lotion With Spf 10 Stratia Soft Touch Aha