Is Imidazolidinyl Urea safe in cosmetics?
Imidazolidinyl Urea has a safety rating of "MODERATE" in our database. EU status: restricted. US status: permitted.
Imidazolidinyl Urea
Also known as: EINECS 254-372-6, UNII-M629807ATL, N,N''-methylenebis(N'-(3-(hydroxymethyl)-2,5-dioxo-4-imidazolidinyl)urea), methanebis(N,N'-(5-ureido-2,4-diketotetrahydroimidazole)-N,N-dimethylol)
INCI: IMIDAZOLIDINYL UREA
Imidazolidinyl Urea (CAS 39236-46-9) is a cosmetic preservative functioning as Preservative; formaldehyde-releasing agent. EU Regulation 1223/2009 status: restricted, max 0.6%. Industrial safety data is also available in the chemical safety database. Same-CAS public records also appear in industrial chemical safety and pharmaceutical data.
View industrial chemical safety profile for CAS 39236-46-9 →
Auto-generated CPSR Part A draft with source citations
Function
Preservative; formaldehyde-releasing agent
Safety Rating
MODERATE
Regulatory Status
EU EU Status
restricted
EU Max Conc.
0.6%
US US Status
permitted
US Notes
Permitted; no concentration cap under FDA/MoCRA; associated with heavier microbial growth in mascara contamination studies
For full compliance data across multiple jurisdictions, use the Substance Compliance tool.
Safety Data
Margin of Safety, dermal absorption, and sensitization profile summaries for Imidazolidinyl Urea.
Calculate MoS for your specific formulation with the MoS Calculator.
Sensitization Profile
Contact sensitization data for Imidazolidinyl Urea based on clinical patch test studies and IFRA standards.
Sensitization Rate
moderate
Allergen Class
preservative
EU Allergen Listed
no
Patch Test Positive Rate
1.2%
Cross-reactivity Group
formaldehyde-releaser-group
Reaction Type
contact-dermatitis
Source: ESSCA 2019/20; IVDK; FDA
Dermal Penetration Profile
Skin absorption and penetration characteristics of Imidazolidinyl Urea, relevant to systemic exposure and MoS calculations.
Absorption %
1-3%
Penetration Level
surface
Penetration Depth
stratum corneum
Molecular Weight
388.3 Da
Log P
-3.2
Systemic Absorption
minimal
Topical Bioavailability
0.5-2%
Safety Margin Factor
low
Vehicle Dependent
Yes — absorption varies by formulation
Source: CIR
Sensitization AOP Dashboard
Adverse Outcome Pathway data across 5 assays (DPRA, KeratinoSens, hCLAT, LLNA, NESIL) aggregated from public sources.
DPRA Cys %
53.54%
DPRA Lys %
19.55%
KeratinoSens IC50
94.7 µM
hCLAT CV75
40.1 µg/mL
LLNA EC3
24%
NESIL
2500 µg/cm²
LLNA: Weak (1B)
GHS: 1B
Human: positive
Source: LLNA: Gerberick et al. (2005); DPRA: Joint Research Centre of the European Union 2013 | Gerberick et al. 2007 [DOI:10.1093/toxsci/kfm064]; KS: Emter et al. 2010 [DOI:10.1016/j.taap.2010.03.009] | Bauch et al. 2011 [DOI:10.1016/j.tiv.2011.05.030]; hCLAT: Urbisch et al. 2015 [DOI:10.1016/j.yrtph.2014.12.008] | Bauch et al. 2011 [DOI:10.1016/j.tiv.2011.05.030]; HPPT: [28] Jordan Jr WP and King SE (1977): https://doi.org/10.1111/j.1600-0536.1977.tb03582.x
HRIPT Human Patch Test Studies
3 human repeat insult patch tests aggregated from dermatological literature.
| Test Type | N | Sensitized | Dose µg/cm² | NESIL µg/cm² | Potency |
|---|---|---|---|---|---|
| HMT | - | 0 | 2500 | - | - |
| HRIPT | - | 0 | 2500 | - | - |
| OECD_DA_Human | - | 0 | - | - | 1B (Weak sensitizer) |
Endocrine Disruptor Evidence (Expanded)
Cross-referenced EDC classifications, mechanism data, and dose-response evidence from EDLists, SIN List, and cosmetic-specific detail sources.
Cosmetic-Specific Mechanism
Category: preservative
Receptor targets: ERα (formaldehyde releaser)
LOEC: N/A (indirect)
EU status: restricted (max 0.6% + labeling)
indirect (via formaldehyde)
Dose-Response Data Points
| Endpoint | Target | Value | Direction |
|---|---|---|---|
| ERα transcriptional activation (indirect via HCHO release) | ERα (indirect) | EC50/IC50: LOEC not precisely reported (~50 µM estimated); LOEC: ~50 µM (estimated); NOEC: not established mixed | weak agonist |
| ARE-Nrf2 pathway activation; sensitization via HCHO release | Nrf2/ARE pathway | EC50/IC50: EC1.5 reported; potency lower than quaternium-15; LOEC: ~50 µg/mL (estimated from Danish EPA data); NOEC: not established mixed | sensitizer |
| Thyroid peroxidase inhibition (indirect via HCHO) | TPO (indirect via HCHO metabolite) | EC50/IC50: No direct IC50; inhibitory capacity proportional to HCHO release rate; LOEC: not established; NOEC: not established mixed | inhibitor (indirect, low potency) |
ECHA REACH Registration
European Chemicals Agency REACH dossier and Substances of Very High Concern listing.
Registration Type
Full
Tonnage Band
100 - 1,000 tonnes
Substance Type
SUBSTANCE
SVHC Candidate
No
EU CosIng Annex Listing
European Commission CosIng database Annex references per Regulation (EC) No 1223/2009.
Annex V — Permitted Preservatives
Max: 0.6%
Expanded Jurisdictional Detail
Additional regulatory detail beyond the 7-jurisdiction summary: Saudi SFDA, Korea MFDS, ASEAN ACD, Japan/Korea, Brazil/India, and cross-jurisdictional restriction entries.
KR Korea MFDS Annex 2 (Restricted)
Category: Preservative. Max: 0.6%. —
SA Saudi SFDA (V - Preservatives)
Max: 0.006.
JPKR Japan/Korea Cosmetics
Japan (Positive (Preservative)): max 0.30
Korea (Restricted): max 0.6%
BRIN Brazil/India Cosmetics
Brazil: Permitted Preservative · max 0,6%
India: Permitted Preservative · max 0.006
Additional Jurisdictional Restrictions (5)
| Jurisdiction | Status | Max % | Product Type |
|---|---|---|---|
| CN | permitted_preservative | 0.6 | All cosmetics |
| IN | permitted_preservative | 0.6 | all cosmetics |
| AU | restricted | 0.6 | preservatives |
| BR | permitted_preservative | 0.6 | - |
| ASEAN | permitted_preservative | 0.6% | All products |
Typical Use Concentrations
Reported concentration ranges per product category from SCCS/CIR/industry sources.
| Product Category | Typical Range | Max Reported | Source |
|---|---|---|---|
| Body Lotion | 0.1–0.5 | 0.5 | CIR |
Additional Ingredient Properties
10 property records from structured ingredient metadata.
allergen_detail
{"eu_allergen_listed": "no", "allergen_class": "preservative", "cross_reactivity_group": "formaldehyde-releaser-group", "patch_test_frequency_pct": "1.2", "sensitization_rate": "moderate", "common_reaction_type": "contact-dermatitis", "ifra_restricted": "no", "source": "ESSCA 2019/20; IVDK; FDA"}
comedogenicity_detail
{"comedogenicity_rating": "0", "irritancy_rating": "3", "skin_type_suitability": "oily,combination", "acne_safe": "caution", "source": "Formaldehyde releaser"}
deodorant
{"cas_number": "39236-46-9", "ingredient_class": "antimicrobial_deodorant", "mechanism_of_action": "bacterial_growth_inhibition", "antiperspirant_efficacy_sweat_reduction_pct": "0", "deodorant_efficacy_hours": "24", "odor_reduction_pct": "60-80", "bacteriostatic": "yes", "bactericidal": "yes", "target_bacteria": "broad_spectrum", "microbiome_impact": "broad", "axillary_microbiome_effect": "varies …
dermal_absorption
{"molecular_weight_da": "388.3", "log_p_value": "-3.2", "skin_penetration_level": "surface", "penetration_depth": "stratum corneum", "absorption_pct": "1-3", "systemic_absorption": "minimal", "penetration_enhancer": "no", "occlusion_effect": "no", "vehicle_dependent": "yes", "skin_barrier_effect": "neutral", "bioavailability_topical_pct": "0.5-2", "safety_margin_factor": "low", "source": "CIR"}
microbiome_impact
{"microbiome_effect": "negative", "prebiotic": "no", "probiotic_compatible": "no", "antimicrobial_spectrum": "broad", "preservative_effect_on_microbiome": "Formaldehyde-releasing; bactericidal to S. epidermidis at <1 hour", "skin_flora_disruption": "severe", "gut_microbiome_risk": "low", "microbiome_recovery_time": "14-28 days", "selective_antimicrobial": "no", "pathogen_inhibition": "S. aureus, S…
pediatric_safety
{"safe_for_newborn_0_6m": "avoid", "safe_for_infant_6_12m": "caution", "safe_for_toddler_1_3y": "caution", "safe_for_child_3_12y": "yes", "safe_for_teen_12_18y": "yes", "pediatric_max_concentration_pct": "0.0", "adult_max_concentration_pct": "0.6", "pediatric_dermal_absorption_factor": "higher", "immature_skin_barrier_risk": "moderate", "oral_ingestion_risk": "moderate", "eye_irritation_risk": "mo…
ph_stability
{"optimal_ph_min": "4.0", "optimal_ph_max": "7.0", "stable_ph_min": "3.5", "stable_ph_max": "8.0", "degrades_above_ph": "8.5", "degrades_below_ph": "3.0", "ph_dependent_function": "Formaldehyde releaser", "formulation_note": "Similar to diazolidinyl urea", "source": "SpecialChem 2025"}
pregnancy_detail
{"pregnancy_safe": "avoid", "breastfeeding_safe": "avoid", "trimester_restriction": "all", "risk_category": "not-rated", "reason": "Formaldehyde releaser", "alternative_ingredient": "Phenoxyethanol; Sodium Benzoate", "source": "dermatology literature"}
Function Categories & List Membership
Cosmetic/Chemical Function Categories
Preservative
Processing aids not otherwise specified
Regulatory List Membership (3)
EU Regulated in Personal Care
EU Restricted for Children (Cosmetics)
EU CosIng Cosmetics Ingredient Database
Expert Verdict
Expert safety assessment and concern-level summary for Imidazolidinyl Urea.
Regulatory Flags
preservative
formaldehyde-releaser
eu-annex-v
eye-area
sensitization-risk
formaldehyde-release
mascara-contamination-concern
ocular-irritant
eu_children_restricted
eu_cosing_listed
Known Synonyms
EINECS 254-372-6
UNII-M629807ATL
N,N''-methylenebis(N'-(3-(hydroxymethyl)-2,5-dioxo-4-imidazolidinyl)urea)
methanebis(N,N'-(5-ureido-2,4-diketotetrahydroimidazole)-N,N-dimethylol)
Chemical Function
Preservative
Processing aids not otherwise specified
Regulatory Lists
Europe; Personal care - body hygiene - hand soap
children; Europe; Personal care
children; Europe; Personal care - specialized bath products - bath salts
children; Europe; Personal care - general moisturizing - hand/body lotion
children; Europe; Personal care
children; Europe; Personal care
children; Europe; Personal care
Europe; Personal care - deodorant
Personal care - general moisturizing
inert_ingredient; non_food_use; Pesticides
Canada; pharmaceutical
Canada; pharmaceutical
Europe; Personal care
active_ingredient; Europe; Pesticides
Australian Status
AICIS status: listed
Cross-Vertical Safety Context
Same-CAS public records found in pharmaceutical data.
SOURCE
ChEMBL / DrugCentral / FAERS
DB_PHARMA CAS match
Pharmaceutical Data
Same-CAS rows from the pharmaceutical spoke database.
Compound
IMIDUREA
ChEMBL ID
CHEMBL65433
Max Phase
-1
Frequently Asked Questions
Is Imidazolidinyl Urea allowed in the EU?
Imidazolidinyl Urea EU regulatory status: restricted. Maximum allowed concentration: 0.6%. This is based on EU Regulation 1223/2009 and its amendments.
What does Imidazolidinyl Urea do in cosmetics?
Imidazolidinyl Urea functions as: Preservative; formaldehyde-releasing agent. It is classified as a Preservative in our database. CAS number: 39236-46-9.
Is Imidazolidinyl Urea used outside cosmetics?
Imidazolidinyl Urea also appears in industrial chemical safety and pharmaceutical data. The cross-vertical cards on this page render same-CAS public rows from the matched databases.
Compliance Tools
Check Imidazolidinyl Urea compliance across multiple jurisdictions:
Ingredient Decoder
Paste a full ingredient list for instant analysis
82 Allergen Checker
Check for EU declarable fragrance allergens
Substance Compliance
Check compliance across multiple jurisdictions
MoS Calculator
Calculate Margin of Safety using SCCS methodology
Heavy Metal Limits
Compare limits across jurisdictions
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