Flavor ingredient regulatory record
5-Methylhexanoic acid
5-Methylhexanoic acid is an acid in the fruity family, FEMA GRAS under FEMA number 3572 (CAS 628-46-6). Its odor is fruity, fatty, sweet, floral.
- FEMA
- 3572
- CAS
- 628-46-6
- JECFA
- 266
- EU FL
- 08.061
- Formula
- C7H14O2
GRAS status: FEMA GRAS, publication 11. Recorded by FDA in the Substances Added to Food inventory under CAS 628-46-6.
Structure
Identity
Also known as: Hexanoic acid, 5-methyl-, Caproic acid, δ-methyl-, Isoenanthic acid, 5-Methylhexylic acid, 5-Methylcaproic acid, NSC 1075, isoenanthic acid, 5-methylcaproic acid, isoamylacetic acid, hexanoic acid, 5-methyl-, 5-methyl hexanoic acid, isovenanthic acid.
Can 5-Methylhexanoic acid be labeled natural?
5-Methylhexanoic acid occurs in nature, so the label depends on the route: 5-Methylhexanoic acid won from a natural source by a physical, enzymatic or microbiological process is natural flavor in the United States, and synthesized 5-Methylhexanoic acid is artificial. The EU and UK follow the same logic without a middle class; Mercosur and Mexico label synthetic 5-Methylhexanoic acid 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
5-Methylhexanoic acid is FEMA GRAS under FEMA number 3572. 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 08.061, Annex I Part A under Regulation (EC) 1334/2008, evaluation status approved (JECFA). The UK retains the same list.
JECFA (WHO / FAO)
JECFA number 266, evaluated at the 49th meeting in 1998. 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. 5-Methylhexanoic acid appears on the EPA Toxic Substances Control Act Chemical Substance Inventory under CAS 628-46-6, where EPA names it Hexanoic acid, 5-methyl-.
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 regulatory flags
| Flag | EPA definition | What it obliges |
|---|---|---|
| PMN | Indicates a commenced PMN substance. | Nothing new. The substance already went through premanufacture review and someone filed a notice of commencement, which is why it is on the Inventory. It is an existing chemical and needs no new premanufacture notice. Read more |
PMN does not establish: The flag records how the substance arrived, not what may be done with it. Check the flags beside it.
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: Fruity, fatty, sweet, floral.
Where it is used
5-Methylhexanoic acid is used in beverage, confection, dairy and savory dishes, typically as a fruity note.
Structurally similar flavor ingredients
Flavor ingredients with a GRAS determination closest to 5-Methylhexanoic acid by structure. Whether one can replace it is a sensory and regulatory call; the reformulation tool works that through.
| Material | FEMA | Similarity | Occurrence |
|---|---|---|---|
| Hexanoic acid | 2559 | 93% | In nature |
| 3-Hexenoic acid | 3170 | 87% | In nature |
| cis-3-Hexenoic acid | 4493 | 87% | In nature |
| 2-Methylhexanoic acid | 3191 | 79% | In nature |
| 6-Methyl-5-hepten-2-ol | 4884 | 74% | In nature |
More acids in this index
2-Methylhexanoic acid · 4-Hydroxy-3-methoxy benzoic acid · o-trans-Coumaric acid · 3-Hydroxybenzoic acid · 4-Methylnonanoic acid · 5&6-Decenoic acid
5-Methylhexanoic acid FAQ
Is 5-Methylhexanoic acid on the FEMA GRAS list?
It is. FEMA number 3572 covers 5-Methylhexanoic acid. It is also codified at 21 CFR 172.515.
What is the FEMA number for 5-Methylhexanoic acid?
The FEMA number for 5-Methylhexanoic acid is 3572 and its CAS registry number is 628-46-6. FEMA files it in the fruity flavor category.
Is 5-Methylhexanoic acid natural or artificial?
Since 5-Methylhexanoic acid is found in nature, US labeling follows how it was obtained: natural flavor from a natural source and a natural process, artificial when 5-Methylhexanoic acid is synthesized. The EU and UK follow the same logic without a middle class; Mercosur and Mexico label synthetic 5-Methylhexanoic acid identical-to-natural.
Is 5-Methylhexanoic acid approved in the EU?
5-Methylhexanoic acid is on the EU Union List of flavouring substances as FL 08.061 (Annex I Part A) under Regulation 1334/2008.
Has JECFA evaluated 5-Methylhexanoic acid?
Yes. JECFA number 266, evaluated at the 49th meeting in 1998. Conclusion: no safety concern at current levels of intake.
What is 5-Methylhexanoic acid used for?
5-Methylhexanoic acid is described as fruity, fatty, sweet, floral. It shows up in beverage, confection, dairy and savory dishes.
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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 5-METHYLHEXANOIC ACID under CAS 628-46-6 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.