Fragrance allergens / Trimethylcyclopentenyl Methylisopentenol
Trimethylcyclopentenyl Methylisopentenol
Trimethylcyclopentenyl Methylisopentenol must be declared in the EU and Northern Ireland, but it is NOT on the Great Britain list: GB retains the older, shorter list and has not adopted Reg (EU) 2023/1545.
Identity
| Name in the ingredient list | Trimethylcyclopentenyl Methylisopentenol |
|---|---|
| CAS / EC number | 67801-20-1 / EC 267-140-4 |
| EU Annex III entry | 339 |
It was ADDED to the EU list by Reg (EU) 2023/1545, so products made for the older 26-entry list may need relabelling.
When it must appear on the label
Trimethylcyclopentenyl Methylisopentenol may be present as a constituent of essential oils or fragrance compounds. It must be named individually in the ingredient list when its total concentration in the finished product exceeds 0.001% in leave-on products (lotions, balms) or 0.01% in rinse-off products (soap, shower gel), summed across every fragrance source in the recipe. Below the threshold it stays within the collective term "Parfum".
United States: no individual fragrance-allergen labelling is in force yet (MoCRA rulemaking pending); fragrance is declared collectively as "Fragrance".
Common questions
Do I have to list Trimethylcyclopentenyl Methylisopentenol on my label?
Trimethylcyclopentenyl Methylisopentenol must be declared in the EU and Northern Ireland, but it is NOT on the Great Britain list: GB retains the older, shorter list and has not adopted Reg (EU) 2023/1545. It must be named individually once it exceeds 0.001% of a leave-on product or 0.01% of a rinse-off product, summed across every fragrance source in the recipe. Below that it stays inside the collective term "Parfum".
What is the CAS number for Trimethylcyclopentenyl Methylisopentenol?
Trimethylcyclopentenyl Methylisopentenol is listed under CAS 67801-20-1 (EC 267-140-4), Annex III entry 339.
Sources
- Commission Regulation (EU) 2023/1545 (OJ L 188, 27.7.2023), as corrected by the corrigendum of 11.11.2025, Annex (EUR-Lex)
Transcribed from the official texts linked above and source-audited against them; a labelling reference, not safety advice. You remain responsible for your product's compliance.
Rule tables last checked 21 August 2026.