Characteristics
- INCI
- Alpha-Isomethyl Ionone
- CAS
-
127-51-5
This is the substance number in the Chemical Abstracts Service registry. The CAS number uniquely identifies a substance regardless of language, trade name, or synonyms.
- EC
-
204-846-3
This is the substance number in the European chemical identification system (EC number), used in European regulatory databases including ECHA/CosIng.
- IUPAC
- 3-Methyl-4-(2,6,6-Trimethyl-2-Cyclohexenyl)-3-Buten-2-One; Methyl-Gamma-Ionone; Gamma-Methylionone
- Functions
- perfuming, skin conditioning
- EU Restr.
-
III/90
EU regulatory status: restricted use. The ingredient is permitted in EU cosmetics but its use and labelling are regulated.
More detail →
Who it's for
Description
That soft, powdery, slightly violet-like scent in a lot of perfumes and scented lotions often has a little help from Alpha-Isomethyl Ionone. It’s one of those fragrance ingredients that mostly works behind the scenes, making a formula smell more rounded, more floral, and a bit more expensive than it probably was. If you have sensitive skin, though, this is one of those names worth noticing rather than ignoring.
From a chemistry point of view, it belongs to the family of fragrance compounds used in everything from perfumes to body care and hair products. The reason it gets so much attention is not because it does anything exciting for your skin barrier or hydration — it doesn’t — but because it can be a fragrance allergen for some people. In patch testing, fragrance ingredients like this one are among the more common triggers of allergic contact dermatitis, especially in people who already react to scented products. So while most people can use it without any drama, your skin may not be thrilled if it is reactive, eczema-prone, or already on the sensitive side.
Regulators in the EU treat it as one of the fragrance allergens that must be separately listed when present above certain thresholds in leave-on products, which is basically the cosmetics world’s way of saying, “please don’t hide this in the generic word fragrance.” That label detail matters because it helps you spot a potential problem before your skin does the detective work for you. In everyday use, most people tolerate it just fine, but if you know your skin tends to throw tantrums over scented products, a fragrance-free formula is usually the safer bet. This ingredient is there for the nose, not for the skin — and your nose may enjoy it while your skin would rather it kept its distance.
More detail
It’s a common fragrance ingredient that is one of the “EU 26 fragrances” that has to be labelled separately (and cannot be simply included in the term “fragrance/perfume” on the label) because of allergen potential. Best to avoid if your skin is sensitive.
Products with Alpha-Isomethyl Ionone (6 994 total)
Most often found in Nivea products (255 items)
