Flavor ingredient regulatory record
alpha-iso-Methylionone
alpha-iso-Methylionone is a ketone in the floral family, FEMA GRAS under FEMA number 2714 (CAS 127-51-5). Its odor is sweet, floral, violet, powdery, fruity.
- FEMA
- 2714
- CAS
- 127-51-5
- JECFA
- 404
- EU FL
- 07.036
- Formula
- C14H22O
- EC
- 204-846-3
GRAS status: FEMA GRAS, publication 3. Recorded by FDA in the Substances Added to Food inventory under CAS 127-51-5.
Structure
Identity
Also known as: 3-Buten-2-one, 3-methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-, 3-Methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-one, α-Cetone, 4-(2,6,6-Trimethyl-2-cyclohexen-1-yl)-3-methyl-3-buten-2-one, α-Ionone, isomethyl-, Isomethyl-α-ionone, Cetone Alpha, NSC 66432, 3-Methyl-4-(2,6,6-trimethylcyclohex-2-enyl)-3-buten-2-one, 3-methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-one, (3e)-3-methyl-4-(2,6,6-trimethylcyclohex-2-en-1-yl)but-3-en-2-one, alpha-isomethylionone.
Can alpha-iso-Methylionone be labeled natural?
Since alpha-iso-Methylionone is found in nature, US labeling follows how it was obtained: natural flavor from a natural source and a natural process, artificial when alpha-iso-Methylionone is synthesized. The EU and UK grant the natural claim only to that natural route; Mercosur and Mexico call synthetic material identical-to-natural.
- United States
- Natural or artificial, by process
- European Union and UK
- Natural only from natural material
- Mercosur and Mexico
- Natural or identical-to-natural
How each market defines the classes: natural vs artificial flavor under 21 CFR 101.22.
Regulatory status, with citations
United States
alpha-iso-Methylionone is FEMA GRAS under FEMA number 2714. It is cited in the Code of Federal Regulations at 21 CFR 172.515.
European Union and United Kingdom
Listed on the Union List of flavouring substances as FL 07.036, Annex I Part A under Regulation (EC) 1334/2008, evaluation status approved (JECFA). The UK retains the same list.
JECFA (WHO / FAO)
JECFA number 404, evaluated at the 51st meeting in 1999. no safety concern at current levels of intake.
Other US flags
Not on the California Proposition 65 list.
TSCA Inventory status
A flavor ingredient is also an industrial chemical. alpha-iso-Methylionone appears on the EPA Toxic Substances Control Act Chemical Substance Inventory under CAS 127-51-5, where EPA names it 3-Buten-2-one, 3-methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-.
Active in US commerce
EPA designates this substance active, so no Notice of Activity Form B is required before manufacturing. What active and inactive mean.
EPA publishes no regulatory flags on this listing. What the flags mean.
From the EPA non-confidential TSCA Inventory, July 2026 release. EPA also maintains a confidential portion it does not publish. Search the Inventory by CAS number.
Odor and taste
Odor: Sweet, floral, violet, powdery, fruity.
Where it is used
alpha-iso-Methylionone is used in fragrance, beverage, confection and baked goods, typically as a floral note.
Structurally similar flavor ingredients
Flavor ingredients with a GRAS determination closest to alpha-iso-Methylionone by structure. Whether one can replace it is a sensory and regulatory call; the reformulation tool works that through.
| Material | FEMA | Similarity | Occurrence |
|---|---|---|---|
| beta-Isomethylionone | 4151 | 98% | In nature |
| alpha-Irone | 2597 | 87% | In nature |
| Dihydro-alpha-ionone | 3628 | 83% | In nature |
| alpha-Ionone | 2594 | 82% | In nature |
| Dehydrodihydroionone | 3447 | 82% | In nature |
More ketones in this index
Methyl-delta-ionone · Methyl-beta- ionone · beta-Isomethylionone · 2-Aminoacetophenone · Ionone · alpha-Ionone
alpha-iso-Methylionone FAQ
Is alpha-iso-Methylionone on the FEMA GRAS list?
It is. FEMA number 2714 covers alpha-iso-Methylionone. It is also codified at 21 CFR 172.515.
What is the FEMA number for alpha-iso-Methylionone?
The FEMA number for alpha-iso-Methylionone is 2714 and its CAS registry number is 127-51-5. FEMA files it in the floral flavor category.
Is alpha-iso-Methylionone natural or artificial?
alpha-iso-Methylionone occurs in nature, so the label depends on the route: alpha-iso-Methylionone won from a natural source by a physical, enzymatic or microbiological process is natural flavor in the United States, and synthesized alpha-iso-Methylionone is artificial. In the EU and UK the natural claim likewise needs the natural route, while Mercosur and Mexico keep a third class, identical-to-natural, for the synthetic material.
Is alpha-iso-Methylionone approved in the EU?
alpha-iso-Methylionone is on the EU Union List of flavouring substances as FL 07.036 (Annex I Part A) under Regulation 1334/2008.
Has JECFA evaluated alpha-iso-Methylionone?
Yes. JECFA number 404, evaluated at the 51st meeting in 1999. Conclusion: no safety concern at current levels of intake.
What is alpha-iso-Methylionone used for?
alpha-iso-Methylionone is described as sweet, floral, violet, powdery, fruity. It shows up in fragrance, beverage, confection and baked goods.
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Sources and attribution. The identity and regulatory facts on this page are taken from the FDA Substances Added to Food inventory, a US government record, which lists this substance as ALPHA-ISOMETHYLIONONE under CAS 127-51-5 and carries its FEMA number, its JECFA flavor number and its 21 CFR citations. The inventory is searchable at FDA. FDA records its technical effect as flavoring agent or adjuvant.
A FEMA GRAS conclusion is reached by the Expert Panel of the Flavor and Extract Manufacturers Association of the United States, and the FEMA number names that conclusion. FEMA publishes its own entry for this substance in the FEMA Flavor Library, which is the authoritative record of what the Panel decided and is worth reading alongside this page.
Ambrose Compliance is not affiliated with, endorsed by, or sponsored by FEMA. FEMA and FEMA GRAS are used here as identifiers for a published regulatory determination, not as marks of any relationship between FEMA and Ambrose.
About this page. Facts come from the FDA Substances Added to Food inventory, the Code of Federal Regulations, the EPA TSCA Inventory, the EU Union List, JECFA and the Ambrose database, with FEMA's published determination cited where it applies; parts of the text are written by Ambrose AI, which can make mistakes. Check the cited source before relying on anything here. This is not regulatory or legal advice.