Flavor ingredient regulatory record
Ethyl 3-hydroxybutyrate
Ethyl 3-hydroxybutyrate is an ester in the fruity family, FEMA GRAS under FEMA number 3428 (CAS 5405-41-4). Its odor is sweet, fruity, buttery, tropical, estery.
- FEMA
- 3428
- CAS
- 5405-41-4
- JECFA
- 594
- EU FL
- 09.522
- Formula
- C6H12O3
- EC
- 226-456-2
GRAS status: FEMA GRAS, publication 8. Recorded by FDA in the Substances Added to Food inventory under CAS 5405-41-4.
Structure
Identity
Also known as: Butanoic acid, 3-hydroxy-, ethyl ester, Butyric acid, 3-hydroxy-, ethyl ester, Butyric acid, β-hydroxy-, ethyl ester, Ethyl 3-hydroxybutanoate, Ethyl β-hydroxybutyrate, 3-Hydroxybutanoic acid ethyl ester, 3-Hydroxybutyric acid ethyl ester, Ethyl DL-3-hydroxybutyrate, (±)-3-Hydroxybutanoic acid ethyl ester, (±)-Ethyl 3-hydroxybutyrate, Ethyl (±)-3-hydroxybutanoate, NSC 42916.
Can Ethyl 3-hydroxybutyrate be labeled natural?
Ethyl 3-hydroxybutyrate occurs in nature, so the label depends on the route: ethyl 3-hydroxybutyrate won from a natural source by a physical, enzymatic or microbiological process is natural flavor in the United States, and synthesized ethyl 3-hydroxybutyrate is artificial. The EU and UK follow the same logic without a middle class; Mercosur and Mexico label synthetic ethyl 3-hydroxybutyrate 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
Ethyl 3-hydroxybutyrate is FEMA GRAS under FEMA number 3428. 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 09.522, Annex I Part A under Regulation (EC) 1334/2008, evaluation status approved (JECFA). The UK retains the same list.
JECFA (WHO / FAO)
JECFA number 594, evaluated at the 53rd meeting in 1999. No safety concern at current levels of intake when used as a flavouring agent.
Other US flags
Not on the California Proposition 65 list.
TSCA Inventory status
A flavor ingredient is also an industrial chemical. Ethyl 3-hydroxybutyrate appears on the EPA Toxic Substances Control Act Chemical Substance Inventory under CAS 5405-41-4, where EPA names it Butanoic acid, 3-hydroxy-, ethyl ester.
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, fruity, buttery, tropical, estery.
Where it is used
Ethyl 3-hydroxybutyrate is used in beverage, confection, dairy, fruit flavors and bakery, typically as a fruity note.
Structurally similar flavor ingredients
Flavor ingredients with a GRAS determination closest to Ethyl 3-hydroxybutyrate by structure. Whether one can replace it is a sensory and regulatory call; the reformulation tool works that through.
| Material | FEMA | Similarity | Occurrence |
|---|---|---|---|
| Methyl 3-hydroxyhexanoate | 3508 | 78% | In nature |
| Ethyl butyrate | 2427 | 68% | In nature |
More esters in this index
cis and trans-p-1(7)8-Menthadien-2-yl acetate · Ethyl maltol isobutyrate · Isoamyl benzoate · 2-Pentyl 2-methylpentanoate · Isoamyl 2-methylbutyrate · Ethyl 3-(methylthio)-trans-2-propenoate
Ethyl 3-hydroxybutyrate FAQ
Is ethyl 3-hydroxybutyrate on the FEMA GRAS list?
It is. FEMA number 3428 covers ethyl 3-hydroxybutyrate. It is also codified at 21 CFR 172.515.
What is the FEMA number for ethyl 3-hydroxybutyrate?
The FEMA number for ethyl 3-hydroxybutyrate is 3428 and its CAS registry number is 5405-41-4. FEMA files it in the fruity flavor category.
Is ethyl 3-hydroxybutyrate natural or artificial?
Since ethyl 3-hydroxybutyrate is found in nature, US labeling follows how it was obtained: natural flavor from a natural source and a natural process, artificial when ethyl 3-hydroxybutyrate is synthesized. The EU and UK follow the same logic without a middle class; Mercosur and Mexico label synthetic ethyl 3-hydroxybutyrate identical-to-natural.
Is ethyl 3-hydroxybutyrate approved in the EU?
Ethyl 3-hydroxybutyrate is on the EU Union List of flavouring substances as FL 09.522 (Annex I Part A) under Regulation 1334/2008.
Has JECFA evaluated ethyl 3-hydroxybutyrate?
Yes. JECFA number 594, evaluated at the 53rd meeting in 1999. Conclusion: No safety concern at current levels of intake when used as a flavouring agent.
What is ethyl 3-hydroxybutyrate used for?
Ethyl 3-hydroxybutyrate is described as sweet, fruity, buttery, tropical, estery. It shows up in beverage, confection, dairy, fruit flavors and bakery.
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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 ETHYL 3-HYDROXYBUTYRATE under CAS 5405-41-4 and carries its FEMA number, its JECFA flavor number. 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.