Alpha-Isomethyl Ionone

Isomethyl Ionone · Orris Butters

CAUTION, A violet-scented fragrance allergen the EU requires named on-label. Real sensitizer, routinely undisclosed here.

What it is

A synthetic violet- and iris-scented fragrance ingredient (CAS 127-51-5) widely used in personal care products.

In this product: Violet/iris fragrance note.

Dose & route, what actually matters

Dermal, leave-on and rinse-off. Skin sensitization via direct contact.

EUROPEAN UNION

Named-disclosure fragrance allergen under EU Cosmetics Regulation Annex III; included in Regulation (EU) 2023/1545 mandatory allergen list. Must be individually listed on EU labels above threshold.

UNITED STATES

No individual disclosure requirement. May appear inside 'Fragrance' on US labels without being named.

The evidence

Alpha-isomethyl ionone is listed in EU Cosmetics Regulation Annex III as a named-disclosure fragrance allergen; included in the expanded list under Regulation (EU) 2023/1545.

regulatory · 2023 · source

California Prop 65: Not listed.

How to avoid it

Fragrance-free products avoid it. EU labels will name it above threshold; US labels typically will not.

Where it hides

Dove Deep Moisture Body Wash →Bath & Body Works A Thousand Wishes Fine Fragrance Mist →

Editorial analysis of publicly available regulatory and peer-reviewed sources. Not medical advice. We name our evidence and link it, including when an ingredient is fine.