Diazolidinyl Urea (INCI: Diazolidinyl Urea, CAS 78491-02-8) is a widely used antimicrobial preservative across cosmetics, personal care, topical pharmaceuticals, and select household formulations.
Functionally, it acts as a formaldehyde-releasing agent, slowly liberating trace formaldehyde to inhibit bacteria, yeast, and mold. While historically valued for its broad-spectrum efficacy and cost efficiency, its reliance on formaldehyde release has triggered increasing regulatory scrutiny and phase-out efforts worldwide.
In the European Union, formaldehyde donors including Diazolidinyl Urea are tightly restricted under Regulation (EC) 1223/2009 Annex V and subject to labeling when the released formaldehyde concentration exceeds 0.001 % (10 ppm).
Several U.S. states-led by California and Washington-have enacted or proposed bans on intentionally added formaldehyde and formaldehyde-releasing ingredients in cosmetics by 2027, aligning with growing international trends toward “formaldehyde-free” preservation.
This review summarizes the regulatory drivers behind replacement, examines viable non-formaldehyde preservation systems, and profiles verified global suppliers to support R&D reformulation across industries.
Why Replace Diazolidinyl Urea
Health & Regulatory Concerns
1. Formaldehyde Release:
Diazolidinyl Urea hydrolyzes to form formaldehyde under typical formulation and storage conditions. Formaldehyde is classified in the EU as a Category 1B carcinogen and skin sensitizer (1) under CLP Regulation 1272/2008.
2. EU Cosmetic Restriction:
Permitted only under Annex V entry 55 with concentration limits ensuring ≤0.2 % free formaldehyde in finished products. From 2022 onward, labeling is required at ≥ 0.001 % free formaldehyde (Reg. (EU) 2022/1181).
3. U.S. Regulatory Trend:
The Modernization of Cosmetics Regulation Act (MoCRA, 2022) and state-level bills in Washington and California prohibit sale of products containing formaldehyde donors from Jan 2027 onward
4. Allergenicity:
Dermatological studies associate Diazolidinyl Urea with allergic contact dermatitis, particularly at > 0.5 % use level or in leave-on formulations.
5. Consumer Perception:
“Formaldehyde-free” labeling has become a market expectation, especially for skin-contact products marketed as clean, vegan, or hypoallergenic.
Functional Rationale
- Performance Limitations: Antimicrobial activity declines in alkaline media (> pH 7.5) and at elevated storage temperatures, where decomposition accelerates.
- Compatibility Issues: Released formaldehyde can react with amines, proteins, or natural extracts, altering actives or colorants.
- Replacement Imperative: Manufacturers seek safer systems offering comparable microbial protection without donor liabilities, supporting global compliance and consumer acceptance.
Regulatory Landscape for Diazolidinyl Urea
| Region / Authority | Current Status | Key Restrictions | Implications for R&D |
| European Union (EC/EFSA/SCCS) | Allowed under Annex V entry 55 | Max 1 % in finished product; label “releases formaldehyde” ≥ 0.001 % | Reformulation recommended; phase-out under discussion. |
| United States (FDA / State Regulations) | Permitted federally; proposed state bans by 2027 | MoCRA + state bans (CA, WA) | Prepare formaldehyde-free replacements by 2026. |
| Canada (Health Canada Hotlist) | Under review | May be restricted to rinse-off only | Monitor updates; avoid in leave-on. |
| ASEAN / India | Allowed with Annex V alignment | Labeling if donor present | Shift toward non-donor blends. |
| Japan (MHLW) | Permitted under preservative list | Formaldehyde ≤ 0.2 % free | Verify in-use free formaldehyde. |
| Codex / WHO / JECFA | Not applicable (cosmetic additive) | JECFA withdrawn formaldehyde specifications for ingestion | Supports precautionary removal in global trade. |
Manufacturers of Non-Formaldehyde Preservative Alternatives
1. Schülke & Mayr GmbH (Germany; Global)
Schülke markets Euxyl PE 9010 (Phenoxyethanol 90 % + Ethylhexylglycerin 10 %) as a broad-spectrum, paraben- and formaldehyde-free preservative effective at 0.5–1.0 %.
Stable across pH 3–10 and heat-resistant up to 80 °C, PE 9010 meets EU Annex V and FDA GRAS criteria. The company provides preservative efficacy data (ISO 11930) and formulation support for cosmetics, pharmaceuticals, and industrial cleaners.
2. Ashland Global Holdings Inc. (USA; Global)
Ashland’s Optiphen series (Optiphen, Optiphen ND, Optiphen Plus) combines Phenoxyethanol, Caprylyl Glycol, and Sorbic Acid derivatives.They offer broad-spectrum protection at 0.5–1.2 % with high solubility and minimal odor.
Optiphen ND is optimized for natural emulsions (pH ≤ 6.5) and Ecocert/COSMOS-approved.
Ashland supports preservative stress testing and claims substantiation.
3. Lonza (Specialty Ingredients, Switzerland; Global)
Lonza (now Arxada) supplies Geogard® Ultra (Gluconolactone + Sodium Benzoate) and Geogard® ET (Phenoxyethanol + Ethylhexylglycerin).
Both are globally accepted, broad-spectrum, and listed in Annex V & EPA Safer Choice programs.Geogard Ultra functions optimally at pH 3–6 and is suitable for natural and clean-label systems.
4. Clariant AG (Switzerland; Global)
Clariant’s Nipaguard SCE is a synergistic preservative blend (Sodium Benzoate, Potassium Sorbate, and Gluconolactone) tailored for “preservative-free claim” formulations.
Effective at 0.75–1.5 % in aqueous and emulsion systems, it is readily biodegradable, COSMOS-approved, and REACH-registered.Clariant provides formulation guidelines for leave-on and rinse-off products with pH ≤ 6.
5. Evonik Industries AG (Germany; Global)
Evonik offers Verstatil BL and Verstatil TBG as next-generation non-donor preservation systems. Verstatil® TBG (Phenylpropanol + Caprylyl Glycol + Glycerin) is effective 0.8–1.2 %, heat-stable ≤ 85 °C, pH 3–9, and suitable for both emulsions and aqueous gels.Compliant with REACH and COSMOS, these blends enable “formaldehyde-free” claims and high sensory acceptance.
6. Symrise AG (Germany; Global)
Symrise’s SymOcide BHO (Benzyl Alcohol + Caprylyl Glycol + Glyceryl Caprylate) provides balanced antibacterial and antifungal coverage at 0.8–1.0 %.
Its blend avoids parabens and formaldehyde donors, maintaining broad pH (4–8) stability and positive sensory profiles.Symrise supplies microbiological challenge data and regulatory dossiers per EU and ASEAN requirements.
7. INOLEX Inc. (USA; Global)
INOLEX’s Lexgard Natural MB (Caprylyl Glycol + Glyceryl Caprylate) and Aminat CG (Phenoxyethanol + Caprylyl Glycol) serve as multifunctional antimicrobials compatible with emulsions, surfactant systems, and wipes.They are biobased, vegan, and COSMOS-approved, supporting clean-label and natural formulations.
Formulation Considerations
- Target Spectrum:
- Phenoxyethanol-based systems: broad antibacterial with moderate antifungal; combine with organic acids for yeast/mold coverage.
- Organic acid systems: effective at acidic pH (< 6); less suited for alkaline cleaners.
- Phenoxyethanol-based systems: broad antibacterial with moderate antifungal; combine with organic acids for yeast/mold coverage.
- Dosage & pH:
- Phenoxyethanol blends: 0.5–1.2 %; stable pH 3–10.
- Organic acid systems: 0.75–1.5 %; effective pH 3–6.
- Glycol/glycerin blends: 0.8–1.2 %; pH 3–9.
- Phenoxyethanol blends: 0.5–1.2 %; stable pH 3–10.
- Compatibility:
Test interactions with surfactants, proteins, and actives; chelating agents (EDTA, gluconates) improve efficacy. Avoid anionic conflict with sorbates/benzoates. - Thermal Stability:
Add preservatives during cool-down (< 60 °C) to prevent degradation. Conduct accelerated aging (45 °C, 12 weeks) and freeze-thaw cycles. - Packaging:
Use oxygen-barrier and low-headspace packaging (HDPE, PET, airless pumps). Avoid metal contact if benzoates or acids are present. - Shelf Life Validation:
Conduct preservative efficacy (ISO 11930), microbial limits (USP <61>, <62>), and sensory stability testing over 6–12 months. - Labeling & Claims:
For global compliance, declare preservatives per INCI; apply allergen labeling if benzyl alcohol ≥ 0.001 % in leave-on products.
Conclusion
Diazolidinyl Urea has served as a cost-effective preservative for decades, yet its formaldehyde-releasing mechanism is no longer aligned with modern regulatory or market expectations.Pending U.S. state bans, EU tightening of formaldehyde-labeling thresholds, and global consumer aversion collectively render the ingredient commercially obsolete for new developments.
Modern non-formaldehyde preservation systems-notably phenoxyethanol/glycol blends, organic acid systems, and multifunctional biobased boosters-offer equivalent antimicrobial efficacy, global regulatory acceptance, and superior sensory performance.
Cross-industry R&D teams should prioritize these alternatives, supported by robust efficacy validation and supplier documentation.
Looking to replace Diazolidinyl Urea with safer, compliant preservatives? Use the form below to connect with our experts for specifications, supplier references, and technical support.
