Flavor ingredient regulatory record
Nootkatone
Nootkatone is a terpene in the citrus family, FEMA GRAS under FEMA number 3166 (CAS 4674-50-4). Its odor is citrusy, woody, grapefruit, fresh.
- FEMA
- 3166
- CAS
- 4674-50-4
- JECFA
- 1398
- EU FL
- 07.089
- Formula
- C15H22O
GRAS status: FEMA GRAS, publication 4. Recorded by FDA in the Substances Added to Food inventory under CAS 4674-50-4.
Structure
Identity
Also known as: 2(3H)-Naphthalenone, 4,4a,5,6,7,8-hexahydro-4,4a-dimethyl-6-(1-methylethenyl)-, (4R,4aS,6R)-, 4βH,5α-Eremophila-1(10),11-dien-2-one, 2(3H)-Naphthalenone, 4,4a,5,6,7,8-hexahydro-4,4a-dimethyl-6-(1-methylethenyl)-, [4R-(4α,4aα,6β)]-, (4R,4aS,6R)-4,4a,5,6,7,8-Hexahydro-4,4a-dimethyl-6-(1-methylethenyl)-2(3H)-naphthalenone, (+)-Nootkatone, Nootkanone, (4R,4AS,6R)-4,4a-dimethyl-6-(prop-1-en-2-yl)-4,4a,5,6,7,8-hexahydronaphthalen-2(3H)-one, (+)-nootkatone, (4r,4as,6r)-4,4a-dimethyl-6-prop-1-en-2-yl-3,4,5,6,7,8-hexahydronaphthalen-2-one, 1(10),11-eremophiladien-2-one, 2(3h)-naphthalenone, 4,4a,5,6,7,8-hexahydro-4,4a-dimethyl-6-(1-methylethenyl)-, (4r,4as,6r)-, 4betah,5alpha-eremophila-1(10),11-dien-2-one.
Can Nootkatone be labeled natural?
Since nootkatone is found in nature, US labeling follows how it was obtained: natural flavor from a natural source and a natural process, artificial when nootkatone is synthesized. The EU and UK follow the same logic without a middle class; Mercosur and Mexico label synthetic nootkatone 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
Nootkatone is FEMA GRAS under FEMA number 3166. 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 07.089, Annex I Part A under Regulation (EC) 1334/2008, evaluation status approved (EFSA). The UK retains the same list.
Purity. At least 93%; secondary component 3-4% dihydronootkatone
JECFA (WHO / FAO)
JECFA number 1398, evaluated at the 63rd meeting in 2004. 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. Nootkatone appears on the EPA Toxic Substances Control Act Chemical Substance Inventory under CAS 4674-50-4, where EPA names it 2(3H)-Naphthalenone, 4,4a,5,6,7,8-hexahydro-4,4a-dimethyl-6-(1-methylethenyl)-, (4R,4aS,6R)-.
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: Citrusy, woody, grapefruit, fresh.
Taste: Bitter, citrus, refreshing.
Where it is used
Nootkatone is used in beverage, flavoring, cosmetics and food products, typically as a citrus note.
Structurally similar flavor ingredients
Flavor ingredients with a GRAS determination closest to Nootkatone by structure. Whether one can replace it is a sensory and regulatory call; the reformulation tool works that through.
| Material | FEMA | Similarity | Occurrence |
|---|---|---|---|
| alpha-iso-Methylionone | 2714 | 78% | In nature |
| beta-Isomethylionone | 4151 | 77% | In nature |
| alpha-Irone | 2597 | 76% | In nature |
| Santalyl acetate | 3007 | 76% | In nature |
| Tetramethyl ethylcyclohexenone | 3061 | 72% | Not determined |
More terpenes in this index
d-Limonene · Valencene · p-Mentha-1,3-diene · d-Limonen-10-ol · Allyl alpha-ionone · Tetrahydrolinalool
Nootkatone FAQ
Does nootkatone have FEMA GRAS status?
Nootkatone holds FEMA GRAS status under FEMA number 3166. It is also codified at 21 CFR 172.515.
How do I cite nootkatone by FEMA or CAS number?
Cite nootkatone as FEMA 3166 or CAS 4674-50-4; both point to the same entry. FEMA files it in the citrus flavor category.
Can nootkatone be labeled a natural flavor?
Nootkatone occurs in nature, so the label depends on the route: nootkatone won from a natural source by a physical, enzymatic or microbiological process is natural flavor in the United States, and synthesized nootkatone is artificial. The EU and UK grant the natural claim only to that natural route; Mercosur and Mexico call synthetic material identical-to-natural.
Can nootkatone be used in the EU and UK?
Nootkatone is on the EU Union List of flavouring substances as FL 07.089 (Annex I Part A) under Regulation 1334/2008.
Has JECFA evaluated nootkatone?
Yes. JECFA number 1398, evaluated at the 63rd meeting in 2004. Conclusion: no safety concern at current levels of intake.
What does nootkatone smell and taste like, and where is it used?
The odor of nootkatone is citrusy, woody, grapefruit, fresh. On the palate it is bitter, citrus, refreshing. Typical uses are beverage, flavoring, cosmetics and food products.
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Guides: What Is FEMA GRAS? · Natural vs artificial · Filing a GRAS notification
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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 NOOTKATONE under CAS 4674-50-4 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.