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Annex II Entry 1666 Allergen 01/12/2021

2-(4-tert-butylbenzyl) propionaldehyde

2-(4-tert-butylbenzyl) propionaldehyde 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: 1666
Allergen

Record details

Chemical name

2-(4-tert-butylbenzyl) propionaldehyde

Chemical / IUPAC name

2-(4-tert-butylbenzyl) propionaldehyde

Regulatory information

Regulation

(EU) 2021/1902

Identified ingredients

EU Fragrance Allergen

This substance is on the list of 26 regulated EU fragrance allergens. It must be declared on the label above threshold concentrations.

BUTYLPHENYL METHYLPROPIONAL

Key data

CAS
80-54-6
EC
201-289-8
Annex
II
Entry number
1666

Inventory links for 2-(4-tert-butylbenzyl) propionaldehyde

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

What Annex II means for 2-(4-tert-butylbenzyl) propionaldehyde

2-(4-tert-butylbenzyl) propionaldehyde is listed as a prohibited substance under Annex II of EU Cosmetics Regulation 1223/2009. No concentration limit applies — the presence of this substance in any cosmetic product placed on the EU market is not permitted regardless of use level.

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. 2-(4-tert-butylbenzyl) propionaldehyde is listed in Annex II of EU Cosmetics Regulation 1223/2009 as a prohibited substance. It must not be present in any cosmetic product placed on the EU market at any concentration.

CAS 80-54-6 is the unique numerical identifier assigned to 2-(4-tert-butylbenzyl) propionaldehyde 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. 2-(4-tert-butylbenzyl) propionaldehyde 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 2-(4-tert-butylbenzyl) propionaldehyde

This page summarizes one Annex II record for 2-(4-tert-butylbenzyl) propionaldehyde 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 2-(4-tert-butylbenzyl) propionaldehyde, but confirm any final regulatory decision against the current official annex wording and source files.

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