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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 CULLUN Tropical Bio-Toning Essence HydroSkinCare Ha² Serum 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 Mario Badescu Glycolic Acid Toner OXY Sensitive Face Wash Elemis Absolute Eye Serum La Tulipe Acne Care Serum Beautifully Scrumptious Body Butter Aloe Vera Erno Laszlo Hydraphel Skin Supplement Hydrating Toner Freeman beauty Detoxifying Charcoal + Black Sugar SunSense Daily Face Spf 50+ This Works Deep Sleep Pillow Spray Nanowhite Fresh Mattifying Moisturiser Skin Actives T-Zone Serum Ziaja Manuka Tree Face Toner 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 O’Keeffe’s Working Hands Hand Cream Purpose Dual Treatment Moisture Lotion With Spf 10 Stratia Soft Touch Aha Mario Badescu Glycolic Eye Cream Nu Skin Liquid Body Lufra Annique 180 Moisture Balm Dermadrate Dry Skin Treatment 10% Urea Cream Freeman beauty Cleansing Apple Cider Vinegar Clay Mask + Scrub Joico Joiwhip Firm Hold Designing Foam 07 Skin doctors pH Balancing Face Cleanser Ziaja Manuka Tree Purifying Night Cream Mario Badescu Acne Facial Cleanser Mario Badescu Cleansing Milk With Carnation & Rice Oil Mario Badescu Enzyme Cleansing Gel Neutrogena Healthy Skin Eye Cream Neutrogena Moisture Spf15 Peter Thomas Roth Therapeutic Sulfur Mask Real Chemistry Fresh-Start Foaming Cleanser Stratia Rewind Ziaja Sensitive Skin Enzyme Peeling Beekman 1802 Pure Goat Milk Hand Cream - Fragrance Free Freeman Anti Stress Dead Sea Minerals Clay Mask Home Health Hyaluronic Acid Moisturizing Cream Mario Summer Shine Body Lotion Mario Badescu Glycolic Foaming Cleanser Mary Kay Timewise Age-Fighting Moisturizer