DIAZOLIDINYL UREA (N-(1,3-bis(hydroxymethyl)-2,5-dioxo-4-imidazolidinyl)-N,N'-bis(hydroxymethyl)urea)
Official label name (INCIInternational name of cosmetic ingredients: the one printed on the pack. name, EU glossary of cosmetic ingredient names), No 8436
- Preservative allowed under conditions (Annex V)
DIAZOLIDINYL UREA (N-(1,3-bis(hydroxymethyl)-2,5-dioxo-4-imidazolidinyl)-N,N'-bis(hydroxymethyl)urea): Preservative allowed under conditions, maximum 0.5% in the ready-for-use preparation (Annex V, entry 46), under Regulation (EC) No 1223/2009. Annexes of the Regulation consulted on 23 October 2026.
Who it concerns
What official classifications and rules say for each group. A classification describes the hazard of the pure substance, not the risk of a product that contains it, which depends on the dose and the exposure.
Prohibition or serious classificationThe text prohibits the substance for this use, or ranks it among the most serious hazards (known or presumed carcinogenic, mutagenic or reprotoxic, identified endocrine disruptor).Worth watchingThe text sets a condition or flags a hazard worth knowing: allergen, suspected effect, condition for children, hazard to the aquatic environment.For informationOfficial information with no condition on a finished product: warning to read, irritation of the pure substance.
Pregnancy and breastfeeding
No classification harmonised by the European Union covers reproduction, the unborn child or breastfeeding for this substance. This does not mean it has been judged to have no effect during pregnancy.
Babies and children
The Cosmetics Regulation sets no age-related condition for this ingredient.
Skin, eyes and allergies
No harmonised classification for sensitisation, irritation or eye damage, and no obligation to label it as an allergen.
Environment
No harmonised classification as hazardous to the aquatic environment, and it is not on ECHAEuropean Chemicals Agency.'s Candidate List as an endocrine disruptor for the environment.
Read on the label
The Cosmetics Regulation requires no warning to be printed for this ingredient.
In plain words
What it is used for
Functions declared by manufacturers:
Preservative: inhibits primarily the development of micro-organisms in cosmetics.
Functions declared in the CosIngThe European Commission's database of cosmetic ingredients. inventory. CosIng, inventory of cosmetic ingredients (INCI names, CAS, EC, functions), retrieved 21 October 2026.
Definitions of functions (decision repealed on 8 May 2020, cited for information). Decision 2006/257/EC, inventory of cosmetic ingredients (definitions of functions), retrieved 22 October 2026.
What the rules say
An ingredient can be used as a preservative only if it appears on the list of Annex V. DIAZOLIDINYL UREA is on it with a maximum concentration.
CosIng, Annex V of Regulation (EC) No 1223/2009 (allowed preservatives), retrieved 23 October 2026, source updated 13 October 2026.
Origin and odour
No natural occurrence recorded in Wikidata (LOTUS database); this does not prove that the ingredient is synthetic.
Basis: one CosIng CAS, with no natural occurrence recorded in this database.
Wikidata: names of substances in six languages and taxa in which they occur (largely from the LOTUS database), retrieved 23 October 2026.
Other names: diazolidinyl urée (French), N-(1,3-bis(hydroxymethyl)-2,5-dioxo-4-imidazolidinyl)-N,N'-bis(hydroxymethyl)urea (English), 1-(1,3-Bis(hydroxymethyl)-2,5-dioxoimidazolidin-4-yl)-1,3-bis(hydroxymethyl)harnstoff (German).
Wikidata: names of substances in six languages and taxa in which they occur (largely from the LOTUS database), retrieved 23 October 2026.
Present in 0.5% of recorded cosmetics (106 out of 19 458), mainly: hair gels, roll-on deodorants, shampoos.
Open Beauty Facts, export of cosmetic products, retrieved 23 October 2026.
Data “Open Beauty Facts and its contributors”, licensed under ODbL 1.0 (opendatacommons.org/licenses/odbl/1-0); derived table distributed under the same licence.
The text of the annexes
Preservative allowed under conditions
- Maximum concentration
- 0.5%
- Entry
- Annex V, No 46
- Substance
- N-(Hydroxymethyl)-N-(dihydroxymethyl-1,3-dioxo-2,5-imidazolidinyl-4)-N'-(hydroxymethyl)urea
- Glossary names
- DIAZOLIDINYL UREA
- CAS
- 78491-02-8
- EC
- 278-928-2
Regulation (EC) No 1223/2009, Annex V, entry 46. CosIng, Annex V of Regulation (EC) No 1223/2009 (allowed preservatives), retrieved 23 October 2026, source updated 13 October 2026.
Entry from Regulation (EC) No 1223/2009, adopted on 30 November 2009.
SCCSEU Scientific Committee on Consumer Safety: it assesses cosmetic ingredients. opinions cited: Opinion on The Determination of certain Formaldehyde Releasers in Cosmetic Products; SCIENTIFIC ADVICE ON the threshold for the warning ‘contains formaldehyde’ in Annex V, preamble point 2 for formaldehyde-releasing substances.
What has changed, and what will change
Dates of the texts that cover this ingredient. A text date may cover several substances: the details of each entry are below.
Annex V, entry 46: introduced or replaced by Regulation (EC) No 1223/2009
Annex V, entry 46: applies from this date
- upcoming
Washington State: Prohibited
Identity
- CosIng identifier
- 33218
- CAS (according to CosIng)
- 78491-02-8
- EC (according to CosIng)
- 278-928-2
- Declared functions
- Preservative
- Wikidata
- Q5272201
- PubChem
- 62277
- ECHA InfoCard
- 100.071.732
- InChIKey
- SOROIESOUPGGFO-UHFFFAOYSA-N
CosIng inventory. CosIng, inventory of cosmetic ingredients (INCI names, CAS, EC, functions), retrieved 21 October 2026.
Wikidata, items with a CosIng identifier (P3073), retrieved 22 October 2026.
Wikidata, PubChem and ECHA links are published only when verified: same CosIng identifier, a single item, matching CAS number.
Elsewhere in the world
Information on other jurisdictions, with no effect on sale in France. What is covered, and what is not yet.
Comparison between countries
Most restrictive status in each country, and the maximum concentration cited. The details and the source of each rule follow.
| Country | Rule | Maximum concentration cited |
|---|---|---|
| European Union | Preservative allowed under conditions | 0.5% |
| United Kingdom | Preservative allowed under conditions | 0.5% |
| Switzerland | EU Regulation applies | 0.5% |
| United States (federal) | No federal rule recorded | not cited |
| Washington State | Prohibited differs from the EU | not cited |
| Japan | No entry in the lists recorded | not cited |
| South Korea | Restricted | 0.5% |
| China | Not on the prohibited lists recorded (lists of allowed substances are not recorded) | not cited |
| Australia | No entry in the lists recorded | not cited |
| Brazil | Allowed under conditions | 0.5% |
United Kingdom (Great Britain)
- Preservative allowed under conditions (Annex V)
Same entries as in the European Union. Their maximum concentrations are compared in the “Comparison between countries” table; other conditions (product types, warnings) may differ.
Annexes II to VI in force. United Kingdom, Annexes II to VI of Regulation (EC) No 1223/2009 as retained and amended, retrieved 21 October 2026.
Contains public sector information licensed under the Open Government Licence v3.0.
Northern Ireland applies EU law.
Switzerland
Regulation (EC) No 1223/2009 applies in Switzerland (Article 54 of the Ordinance on Foodstuffs and Utility Articles).
Switzerland, FDHA Ordinance on Cosmetic Products (OCos, SR 817.023.31), consolidated version, retrieved 22 October 2026.
United States, federal rules
None of the integrated sections of the federal code (21 CFR 700.11 to 700.27 and 250.250) targets this name. The FDA does not publish a list of allowed ingredients.
United States, 21 CFR part 700 and section 250.250 (FDA rules on cosmetic ingredients), eCFR, retrieved 21 October 2026.
The eCFR is not an official legal edition of the Code of Federal Regulations.
Washington State (United States)
- Prohibited: Diazolidinyl Urea
libérateur n° 2, from 1 January 2027. Prohibited when intentionally added; a retailer in the state may sell existing stock until January 1, 2028.
Washington State, Toxic-Free Cosmetics Act: RCW 70A.560.020 and WAC 173-339, retrieved 22 October 2026.
South Korea
- Restricted: 디아졸리디닐우레아 (N-(히드록시메칠)-N-(디히드록시메칠-1,3-디옥소-2,5-이미다졸리디닐-4)-N'-(히드록시메칠)우레아)
별표 2, 보존제 성분 (preservatives), entry 5, page 1. Limit: 0.5%.
South Korea, MFDS Regulation on Safety Standards for Cosmetics, Notification 2026-19, retrieved 22 October 2026.
Source: 식품의약품안전처 (MFDS), 화장품 안전기준 등에 관한 규정, via law.go.kr; table formatted by the publisher of this site.
Brazil
- Allowed under conditions: N-(hidroximetil)-N-(dihidroximetil-1,3-dioxo-2,5-imidazolidinil-4)-N’(hidroximetil)urea (DIAZOLIDINYL UREA)
RDC 528/2021, Anexo (allowed preservatives), entry 41, page 4. Limit: 0.5%.
Brazil, ANVISA resolutions RDC 529/2021, 528/2021, 600/2022 and 628/2022, retrieved 22 October 2026.
Source: ANVISA. Text of the adopted draft resolutions, as the Official Journal could not be accessed; the 2021 lists of prohibited substances and preservatives were compared with the copy of the published text distributed by the State of Paraná, the 2022 lists of UV filters and colorants were not.
Recorded cosmetics that contain it
106 recorded products list it, according to Open Beauty Facts contributors. Records are dated: the formula may have changed. See the list (in French).
Open Beauty Facts, export of cosmetic products, retrieved 23 October 2026.
Data “Open Beauty Facts and its contributors”, licensed under ODbL 1.0 (opendatacommons.org/licenses/odbl/1-0); derived table distributed under the same licence.
Glossary: Commission Implementing Decision (EU) 2025/1175. Page updated on 23 October 2026.