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Annex II Entry 1380 Allergen 27/07/2020

3 and 4-(4-Hydroxy-4-methylpentyl)cyclohex-3-ene-1-carbaldehyde

3 and 4-(4-Hydroxy-4-methylpentyl)cyclohex-3-ene-1-carbaldehyde is listed in Annex II as a prohibited substance for cosmetic products placed on the EU market.

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Prohibited substance— Annex II, EU Regulation 1223/2009
Entry: 1380
Allergen
Declared fragrance allergen

This substance is on the EU list of fragrance allergens that must be named individually in the ingredient list, rather than being covered by the word "parfum", once it exceeds 0.001% in a leave-on product or 0.01% in a rinse-off product.

This substance is also prohibited in EU cosmetics, so the declaration applies only to an unintended trace that Article 17 tolerates — not to anything deliberately added. See the allergen record

Chemical identity and properties

PubChem 2D chemical structure for CAS 31906-04-4
CAS 31906-04-4PubChem CID 91604

Liral

IUPAC name
4-(4-hydroxy-4-methylpentyl)cyclohex-3-ene-1-carbaldehyde
Molecular formula
C13H22O2
Molecular weight
210.31 g/mol
Exact mass
210.161979940 Da
XLogP3
1.7
Topological polar surface area
37.3 Ų
Hydrogen-bond donors
1
Hydrogen-bond acceptors
2
Covalent units
1
Defined stereocentres
0

Also known as

hydroxyisohexyl 3-cyclohexene carboxaldehyde4-(4-Hydroxy-4-methylpentyl)-3-cyclohexene-1-carboxaldehyde3-Cyclohexene-1-carboxaldehyde, 4-(4-hydroxy-4-methylpentyl)-QUE43B9Z2QRefChem:789491250-863-4Lyral4-(4-Hydroxy-4-methylpentyl)cyclohex-3-enecarbaldehyde
16 more reported names
4-(4-Hydroxy-4-methylpentyl)-cyclohex-3-enecarbaldehydeEINECS 250-863-4UNII-QUE43B9Z2QBRN 2046455MSK3313Tox21_200394FS-4825HY-W035214hydroxymethylpentylcyclohexenecarboxaldehydeCAS-31906-04-4DB-068548CS-0085252HYDROXYMETHYLPENTYLCYCLOHEXENE-CARBOXYALDEHYDE4-(4-hydroxy-4-methylpentyl)cyclohex-3-encarbaldehyd4(4-hydroxy-4-methylpentyl)3-cyclohexene carboxaldehyde4-(4-hydroxy-4-methylpentyl)-3-cyclohexenecarbaldehyde
Open full PubChem recordPubChem annotations3D structure image
External database identifiers

Retrieved from NIH PubChem on 2026-09-02 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.

PubChem 2D chemical structure for CAS 51414-25-6
CAS 51414-25-6PubChem CID 162105

3-(4-Hydroxy-4-methylpentyl)cyclohex-3-ene-1-carbaldehyde

IUPAC name
3-(4-hydroxy-4-methylpentyl)cyclohex-3-ene-1-carbaldehyde
Molecular formula
C13H22O2
Molecular weight
210.31 g/mol
Exact mass
210.161979940 Da
XLogP3
1.7
Topological polar surface area
37.3 Ų
Hydrogen-bond donors
1
Hydrogen-bond acceptors
2
Covalent units
1
Defined stereocentres
0

Also known as

EINECS 257-187-93-(4-Hydroxy-4-methylpentyl)-3-Cyclohexene-1-carboxaldehyde3-Cyclohexene-1-carboxaldehyde, 3-(4-hydroxy-4-methylpentyl)-RefChem:493123257-187-93-(4-hydroxy-4-methylpentyl)cyclohex-3-enecarbaldehyde3-(4-hydroxy-4-methylpentyl)-1-cyclohex-3-enecarboxaldehydeOLXLPKQCGWYRFQ-UHFFFAOYSA-N
Open full PubChem recordPubChem annotations3D structure image
External database identifiers

Retrieved from NIH PubChem on 2026-09-02 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.

Record details

Chemical name

3 and 4-(4-Hydroxy-4-methylpentyl)cyclohex-3-ene-1-carbaldehyde

Chemical / IUPAC name

3- and 4-(4-Hydroxy-4-methylpentyl) cyclohex-3-ene-1-carbaldehyde (HICC)

Regulatory information

Regulation

(EU) 2017/1410

See every entry this act set

SCCS opinions

Identified ingredients

EU Fragrance Allergen

This substance is linked to an EU fragrance-allergen reference. Check the current Annex III entry for the declaration threshold and any additional conditions.

HYDROXYISOHEXYL 3-CYCLOHEXENE CARBOXALDEHYDE

Key data

CAS
31906-04-4 / 51414-25-6
EC
250-863-4 / 257-187-9
Annex
II
Entry number
1380

Inventory links for 3 and 4-(4-Hydroxy-4-methylpentyl)cyclohex-3-ene-1-carbaldehyde

Direct matches are limited for this record, so nearby entries from Annex II are shown as well.

What Annex II means for 3 and 4-(4-Hydroxy-4-methylpentyl)cyclohex-3-ene-1-carbaldehyde

3 and 4-(4-Hydroxy-4-methylpentyl)cyclohex-3-ene-1-carbaldehyde is listed as a prohibited substance under Annex II of EU Cosmetics Regulation 1223/2009 and must not be intentionally added. Article 17 separately addresses unintended small quantities that are technically unavoidable under good manufacturing practice and compatible with the Article 3 safety requirement.

Formulators must screen their ingredients and raw materials to ensure none contain this substance. Suppliers should provide documentation confirming absence when requested.

This record is linked to 1 CosIng inventory ingredient for name and identifier cross-reference. The page also surfaces 12 related annex records with overlapping identifiers, annex logic or naming patterns.

Compliance checklist

  • Verify this substance is absent from all raw materials and finished formulations.
  • Request absence confirmation or CoA from raw material suppliers.
  • Document the screening result in the Product Information File (PIF).
  • This substance is a regulated fragrance allergen. Declare it on the label by INCI name above 0.001% in leave-on or 0.01% in rinse-off products.

Frequently asked questions

Yes. 3 and 4-(4-Hydroxy-4-methylpentyl)cyclohex-3-ene-1-carbaldehyde is listed in Annex II of EU Cosmetics Regulation 1223/2009 and is prohibited as an intentionally added cosmetic ingredient. Article 17 provides a narrow exception for unintended small quantities that are technically unavoidable under good manufacturing practice, provided the product remains safe under Article 3.

CAS 31906-04-4 / 51414-25-6 is the unique numerical identifier assigned to 3 and 4-(4-Hydroxy-4-methylpentyl)cyclohex-3-ene-1-carbaldehyde by the Chemical Abstracts Service. In cosmetic compliance work, the CAS number is used to cross-reference the substance across regulatory databases, raw material specifications and safety assessment reports. Multiple EU annex entries may share the same CAS number if the same substance appears under different conditions or in different annexes.

Yes. 3 and 4-(4-Hydroxy-4-methylpentyl)cyclohex-3-ene-1-carbaldehyde is on the EU list of regulated fragrance allergens. It must be declared on the cosmetic product label by its INCI name when present above 0.001% in leave-on products or above 0.01% in rinse-off products, as required by EU Cosmetics Regulation 1223/2009.

Use the INCI Checker tool on this site to paste your full ingredient list (INCI) and scan it against all Annex II–VI entries. The tool highlights any ingredients that match restricted, prohibited or allergen-flagged records. This is useful for rapid compliance screening of finished product formulas or raw material declarations.
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Source note for Annex II record 3 and 4-(4-Hydroxy-4-methylpentyl)cyclohex-3-ene-1-carbaldehyde

This page summarizes one Annex II record for 3 and 4-(4-Hydroxy-4-methylpentyl)cyclohex-3-ene-1-carbaldehyde from public European Commission cosmetic materials and adds linked inventory or identifier matches when available.

Use this record page to review Annex II conditions for 3 and 4-(4-Hydroxy-4-methylpentyl)cyclohex-3-ene-1-carbaldehyde, but confirm any final regulatory decision against the current official annex wording and source files.

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