Alpha-Isomethyl Ionone
- Fragrances
- CAS 127-51-5
- IUPAC: 3-Methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-one
Alpha-Isomethyl Ionone (CAS 127-51-5) appears in 1 of the 1,812 car-care products CarCareTruth tracks (as of June 2026).
A synthetic fragrance ionone compound. Classified as a potential skin sensitizer (H317) under GHS at ingredient level. Also classified H315 (skin irritation) and H319 (eye irritation) at ingredient level. Aquatic chronic toxicity Cat 2 (H411) at ingredient level; not classified at typical mixture concentrations in car care products. EU SDS EUH208 fragrance sensitizer disclosure applies when used in products containing it at or above 0.01%.
Alpha-isomethyl ionone (alpha-iso-methylionone) is a synthetic fragrance compound that imparts woody, violet, and iris scent notes. It is widely used in perfumery and scented consumer products at low concentrations.
At ingredient level it carries H317 (skin sensitizer 1B), H315, H319, and H411 (aquatic chronic Cat 2) classifications. At typical use concentrations in car care aerosol products (0.1–1%), it contributes a fragrance sensitizer obligation under EU CLP (EUH208 disclosure). Aquatic toxicity concern exists at ingredient level but is not typically carried to mixture-level classification at car care use concentrations.
Health & environment profile
- VOC
- no
- Prop 65 listed
- no
- Asthmagen
- no
- EPA Safer Choice
- no
- Aquatic toxicity
- yes
- Biodegradable
- no
- Bioaccumulative
- no
- Persistent
- no
- Ozone depleting
- no
- Microplastic
- no
- PFAS
- no
- Env. score
- 5/5
Common questions about Alpha-Isomethyl Ionone
- What is Alpha-Isomethyl Ionone used for in car care?
- Fragrance — woody, violet, iris scent note
- Is Alpha-Isomethyl Ionone a VOC?
- No. Alpha-Isomethyl Ionone is not classified as a volatile organic compound (VOC).
- Is Alpha-Isomethyl Ionone on California's Proposition 65 list?
- No. Alpha-Isomethyl Ionone is not on California's Proposition 65 list.
1 product contain this
Turtle Wax Power Out! Odor-X Whole Car Blast (2.5 oz)Prop 65odor-eliminator
Related
Health and environment notes translate the manufacturer Safety Data Sheet, the GHS classification, and authoritative regulatory listings (California Prop 65, EPA). Not medical advice. They describe the ingredient itself; whether a hazard applies to a finished product depends on its concentration and how it's used.