Flavor ingredient regulatory record
4-Hydroxybutyric acid lactone
4-Hydroxybutyric acid lactone is a lactone in the fruity family, FEMA GRAS under FEMA number 3291 (CAS 96-48-0). Its odor is sweet, creamy, fruity, coconut.
- FEMA
- 3291
- CAS
- 96-48-0
- JECFA
- 219
- EU FL
- 10.006
- Formula
- C4H6O2
- EC
- 202-509-5
GRAS status: FEMA GRAS, publication 5. Recorded by FDA in the Substances Added to Food inventory under CAS 96-48-0.
Structure
Identity
Also known as: 2(3H)-Furanone, dihydro-, Dihydro-2(3H)-furanone, NIH 10540, γ-BL, Butyrolactone, 1,4-Butanolide, γ-Butyrolactone, 4-Hydroxybutanoic acid lactone, γ-Hydroxybutyric acid lactone, Butanoic acid, 4-hydroxy-, γ-lactone, Butyric acid lactone, Tetrahydro-2-furanone.
Can 4-Hydroxybutyric acid lactone be labeled natural?
The process decides for 4-Hydroxybutyric acid lactone. It occurs in nature, so a natural-source, natural-process material is natural flavor in the US and synthetic 4-Hydroxybutyric acid lactone is artificial. 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
4-Hydroxybutyric acid lactone is FEMA GRAS under FEMA number 3291. 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 10.006, Annex I Part A under Regulation (EC) 1334/2008, evaluation status approved (JECFA). The UK retains the same list.
JECFA (WHO / FAO)
JECFA number 219, evaluated at the 49th meeting in 1997. 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. 4-Hydroxybutyric acid lactone appears on the EPA Toxic Substances Control Act Chemical Substance Inventory under CAS 96-48-0, where EPA names it 2(3H)-Furanone, dihydro-.
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, creamy, fruity, coconut.
Taste: Sweet, creamy, slightly tangy.
Where it is used
4-Hydroxybutyric acid lactone is used in beverage, dairy, confection, bakery and desserts, typically as a fruity note.
Structurally similar flavor ingredients
Flavor ingredients with a GRAS determination closest to 4-Hydroxybutyric acid lactone by structure. Whether one can replace it is a sensory and regulatory call; the reformulation tool works that through.
| Material | FEMA | Similarity | Occurrence |
|---|---|---|---|
| 4,5-Dihydro-3(2H) thiophenone | 3266 | 90% | In nature |
| gamma-Valerolactone | 3103 | 78% | In nature |
| Propionic acid | 2924 | 75% | In nature |
| Pyruvaldehyde | 2969 | 74% | In nature |
| 1-Pyrroline | 3898 | 74% | In nature |
More lactones in this index
Hydroxynonanoic acid delta-lactone · 5-Hydroxy-2,4-decadienoic acid delta-lactone · (+/-)-(2,6,6,-Trimethyl-2-hydroxycyclohexylidene)acetic acid gamma-lactone · Dihydrocoumarin · gamma-Valerolactone · 4,4-Dibutyl-gamma-butyrolactone
4-Hydroxybutyric acid lactone FAQ
Is 4-Hydroxybutyric acid lactone FEMA GRAS?
Yes. The FEMA Expert Panel lists 4-Hydroxybutyric acid lactone as GRAS under FEMA number 3291. The Code of Federal Regulations lists it at 21 CFR 172.515.
What are the FEMA and CAS numbers for 4-Hydroxybutyric acid lactone?
4-Hydroxybutyric acid lactone is FEMA 3291, CAS 96-48-0. Its flavor category is fruity.
How is 4-Hydroxybutyric acid lactone described, and where does it show up?
Flavorists describe 4-Hydroxybutyric acid lactone as sweet, creamy, fruity, coconut. On the palate it is sweet, creamy, slightly tangy. It is used in beverage, dairy, confection, bakery and desserts.
What did JECFA conclude about 4-Hydroxybutyric acid lactone?
JECFA evaluated 4-Hydroxybutyric acid lactone at the 49th meeting in 1997 under JECFA number 219. The panel concluded: No safety concern at current levels of intake when used as a flavouring agent.
Is 4-Hydroxybutyric acid lactone on the EU Union List?
Yes. FL 10.006 is the Union List entry for 4-Hydroxybutyric acid lactone, annex I Part A, under Regulation 1334/2008, and the UK keeps the same list.
Does 4-Hydroxybutyric acid lactone count as natural in the US and the EU?
Nature makes 4-Hydroxybutyric acid lactone, which is why the US label turns on process. A natural route gives natural flavor; synthesis gives artificial 4-Hydroxybutyric acid lactone, same molecule. 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.
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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 4-HYDROXYBUTANOIC ACID LACTONE under CAS 96-48-0 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.