Flavor ingredient regulatory record
1,6-Hexalactam
1,6-Hexalactam is a lactam in the fruity family, FEMA GRAS under FEMA number 4235 (CAS 105-60-2). Its odor is sweet, creamy, milky, nutty, slightly floral.
- FEMA
- 4235
- CAS
- 105-60-2
- JECFA
- 1594
- EU FL
- 16.052
- Formula
- C6H11NO
- EC
- 203-313-2
GRAS status: FEMA GRAS, publication 22. Recorded by FDA in the Substances Added to Food inventory under CAS 105-60-2.
Structure
Identity
Also known as: 2H-Azepin-2-one, hexahydro-, Hexahydro-2H-azepin-2-one, Aminocaproic lactam, Caprolactam, ε-Caprolactam, 2-Ketohexamethylenimine, 2-Oxohexamethylenimine, Hexanoic acid, 6-amino-, cyclic lactam, Hexahydro-2-azepinone, 2-Azacycloheptanone, 6-Caprolactam, 6-Hexanelactam.
Can 1,6-Hexalactam be labeled natural?
The process decides for 1,6-Hexalactam. It occurs in nature, so a natural-source, natural-process material is natural flavor in the US and synthetic 1,6-Hexalactam is artificial. The EU and UK follow the same logic without a middle class; Mercosur and Mexico label synthetic 1,6-Hexalactam 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
1,6-Hexalactam is FEMA GRAS under FEMA number 4235. 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 16.052, Annex I Part A under Regulation (EC) 1334/2008, evaluation status approved (EFSA). The UK retains the same list.
JECFA (WHO / FAO)
JECFA number 1594.
Other US flags
Not on the California Proposition 65 list.
TSCA Inventory status
A flavor ingredient is also an industrial chemical. 1,6-Hexalactam appears on the EPA Toxic Substances Control Act Chemical Substance Inventory under CAS 105-60-2, where EPA names it 2H-Azepin-2-one, hexahydro-.
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, milky, nutty, slightly floral.
Taste: Umami, slightly sweet, creamy.
Where it is used
1,6-Hexalactam is used in dairy, confection, savory dishes and snacks, typically as a fruity note.
Structurally similar flavor ingredients
Flavor ingredients with a GRAS determination closest to 1,6-Hexalactam by structure. Whether one can replace it is a sensory and regulatory call; the reformulation tool works that through.
| Material | FEMA | Similarity | Occurrence |
|---|---|---|---|
| epsilon-Decalactone | 3613 | 75% | In nature |
| Cyclohexanone | 3909 | 53% | In nature |
| Piperidine | 2908 | 51% | In nature |
| 2-Methylpiperidine | 4244 | 48% | In nature |
| Piperazine | 4250 | 46% | In nature |
More lactams in this index
1,6-Hexalactam FAQ
Is 1,6-Hexalactam on the FEMA GRAS list?
It is. FEMA number 4235 covers 1,6-Hexalactam. The Code of Federal Regulations lists it at 21 CFR 172.515.
What is the FEMA number for 1,6-Hexalactam?
The FEMA number for 1,6-Hexalactam is 4235 and its CAS registry number is 105-60-2. Its flavor category is fruity.
What is 1,6-Hexalactam used for?
1,6-Hexalactam is described as sweet, creamy, milky, nutty, slightly floral. On the palate it is umami, slightly sweet, creamy. It shows up in dairy, confection, savory dishes and snacks.
What did JECFA conclude about 1,6-Hexalactam?
JECFA evaluated 1,6-Hexalactam under JECFA number 1594.
Is 1,6-Hexalactam approved in the EU?
Yes. FL 16.052 is the Union List entry for 1,6-Hexalactam, annex I Part A, under Regulation 1334/2008, and the UK keeps the same list.
Is 1,6-Hexalactam natural or artificial?
Nature makes 1,6-Hexalactam, which is why the US label turns on process. A natural route gives natural flavor; synthesis gives artificial 1,6-Hexalactam, same molecule. The EU and UK grant the natural claim only to that natural route; Mercosur and Mexico call synthetic material identical-to-natural.
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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 CAPROLACTAM under CAS 105-60-2 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.