Alpha-Isomethyl Ionone
Alpha-isomethyl ionone
- Role
- A scent molecule from the ionone group used in fragrances.
- Catalog formulas
- 27
- Type
- Scent
- Verified
- 06.11.2026
What does this ingredient do in an antiperspirant?
One of the components of the fragrance blend that the EU requires to be named separately above the labelling threshold.
Part of a system, not a label in isolation
In an antiperspirant or deodorant it only contributes to the scent and does not reduce sweating. Its presence in the list means the product is fragranced.
In the EU it is on the list of fragrance allergens (Regulation 1223/2009, Annex III, entry 90): it must be named separately in the ingredient list above 0.001% in leave-on and 0.01% in rinse-off products.
The 2012 SCCS opinion lists it as an established contact allergen in humans, with 11 to 100 positive patch-test reactions reported.
This is one specific substance. Parfum is the umbrella name for the whole fragrance blend, whereas the EU requires this component to be named separately.
Products containing Alpha-Isomethyl Ionone
Links are based on the complete published INCI list for the exact product version.
Sources
The conclusions apply to the stated conditions and jurisdictions, not automatically to every concentration or product.
- CosIng Checker: Annex III, entry 90 (Alpha-Isomethyl Ionone) Supports: restrictions, allergen labelling
- SCCS/1459/11: Opinion on fragrance allergens in cosmetic products Supports: allergenicity assessment