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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

PROSACEA Medicated Rosacea Gel HydroSkinCare Ha² Serum Treatment (2.5% Benzoyl Peroxide) Fruit of the Earth Aloe Vera 100% Erno Laszlo Hydraphel Skin Supplement Hydrating Toner Freeman beauty Detoxifying Charcoal + Black Sugar SunSense Daily Face Spf 50+ Skin Actives T-Zone Serum Alpha Skin Care Intensive Renewal Serum, 14% Glycolic Aha DrGL Skin Repair Holy Snails Shark Sauce Invisible Zinc Environmental Skin Protector Spf30+ Nip+fab body Cellulite Fix Purpose Dual Treatment Moisture Lotion With Spf 10 Stratia Soft Touch Aha Mario Badescu Glycolic Eye Cream Dermadrate Dry Skin Treatment 10% Urea Cream Freeman beauty Cleansing Apple Cider Vinegar Clay Mask + Scrub Ziaja Manuka Tree Purifying Night Cream Mario Badescu Acne Facial Cleanser Mario Badescu Cleansing Milk With Carnation & Rice Oil Mario Badescu Enzyme Cleansing Gel Real Chemistry Fresh-Start Foaming Cleanser Stratia Rewind Ziaja Sensitive Skin Enzyme Peeling Home Health Hyaluronic Acid Moisturizing Cream Mario Badescu Glycolic Foaming Cleanser Mary Kay Timewise Age-Fighting Moisturizer Joico Colour Endure Violet Shampoo Neutrogena Oil-Free Moisture For Sensitive Skin Neutrogena Oil-Free Moisture-Combination Skin Moisturiser Stratia Velvet Cleansing Milk Biore Pore Unclogging Scrub Nature Pure Teen Skin Nourisher Black Tie Cosmetics Sheer Glo Manuka Doctor Apiclear Blemish Cream O’Keeffe’s O'Keeffe'S Skin Repair Body Lotion DevaCurl One Condition Original Gold Bond Ultimate Healing Lotion With Aloe Fragrance-Free Mario Badescu Hydro Moisturizer With Vitamin C gatineau Ultimate Smoothing Serum DevaCurl No-Poo Original DevaCurl No-Poo® Decadence DevaCurl One Condition™ Decadence MINISO Rose Hydrating Toner OGX Shampoo Thick&Full Biotin & Collagen Skin + Pharmacy Advanced Acne Therapy Overnight Salicylic Acid Lotion Delectable Coconut & Cream Body Lotion Peter Thomas Roth Ultra-Light Oil-Free Moisturizer Mary Kay Time Wise Microdermabrasion