Flavor ingredient regulatory record
3-Mercaptohexanol
3-Mercaptohexanol is a thiol in the sulfur family, FEMA GRAS under FEMA number 3850 (CAS 51755-83-0). Its odor is garlic, onion, pungent, earthy, sulfurous.
- FEMA
- 3850
- CAS
- 51755-83-0
- JECFA
- 545
- Formula
- C6H14OS
GRAS status: FEMA GRAS, publication 18. Recorded by FDA in the Substances Added to Food inventory under CAS 51755-83-0.
Structure
Identity
Also known as: 1-Hexanol, 3-mercapto-, 3-Mercapto-1-hexanol, 3-Sulfanylhexan-1-ol, 3-mercapto-1-hexanol, 3-sulfanylhexan-1-ol, 1-hexanol, 3-mercapto-, 3-mercaptohexan-1-ol, 3-thiohexan-1-ol, 3-sulphanylhexan-1-ol, 3-sulfanyl-1-hexanol, 3-mercapto-1-hexanol; 3-mercaptohexanol; 3-sulfanylhexan-1-ol, 3-mercapto-hexan-1-ol.
Can 3-Mercaptohexanol be labeled natural?
Since 3-Mercaptohexanol is found in nature, US labeling follows how it was obtained: natural flavor from a natural source and a natural process, artificial when 3-Mercaptohexanol is synthesized. The EU and UK follow the same logic without a middle class; Mercosur and Mexico label synthetic 3-Mercaptohexanol 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
3-Mercaptohexanol is FEMA GRAS under FEMA number 3850. It is cited in the Code of Federal Regulations at 21 CFR 172.515.
European Union and United Kingdom
No EU FL number is on file for 3-Mercaptohexanol. That is not a finding either way. The Union List covers defined flavouring substances, so natural complex materials are handled as flavouring preparations under Parts B to F and never receive a number, and substances used as additives sit under Regulation 1333/2008 instead. Confirm the position before EU or UK use.
JECFA (WHO / FAO)
JECFA number 545, 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. Listed on the EPA TSCA inventory.
TSCA Inventory status
A flavor ingredient is also an industrial chemical. 3-Mercaptohexanol appears on the EPA Toxic Substances Control Act Chemical Substance Inventory under CAS 51755-83-0, where EPA names it 1-Hexanol, 3-mercapto-.
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: Garlic, onion, pungent, earthy, sulfurous.
Where it is used
3-Mercaptohexanol is used in savory dishes, seasonings, meat products and sauces, typically as a sulfur note.
Structurally similar flavor ingredients
Flavor ingredients with a GRAS determination closest to 3-Mercaptohexanol by structure. Whether one can replace it is a sensory and regulatory call; the reformulation tool works that through.
| Material | FEMA | Similarity | Occurrence |
|---|---|---|---|
| 3-Mercaptohexanal | 4585 | 92% | Not determined |
| cis-3-Hexen-1-ol | 2563 | 86% | In nature |
| 2,4-Hexadien-1-ol | 3922 | 82% | In nature |
| (+/-) 3-(Ethylthio)butanol | 4282 | 75% | Not determined |
| cis-3-Hexenoic acid | 4493 | 73% | In nature |
More thiols in this index
4-Mercapto-4-methyl-2-hexanone · Phenyl disulfide · 4-(Methylthio)butanal · 2-Methyltetrahydrothiophen-3-one · 2,3 or 10-Mercaptopinane · S-Methyl benzothioate
3-Mercaptohexanol FAQ
Does 3-Mercaptohexanol have FEMA GRAS status?
3-Mercaptohexanol holds FEMA GRAS status under FEMA number 3850. It is also codified at 21 CFR 172.515.
How do I cite 3-Mercaptohexanol by FEMA or CAS number?
Cite 3-Mercaptohexanol as FEMA 3850 or CAS 51755-83-0; both point to the same entry. FEMA files it in the sulfur flavor category.
Can 3-Mercaptohexanol be labeled a natural flavor?
3-Mercaptohexanol occurs in nature, so the label depends on the route: 3-Mercaptohexanol won from a natural source by a physical, enzymatic or microbiological process is natural flavor in the United States, and synthesized 3-Mercaptohexanol is artificial. The EU and UK grant the natural claim only to that natural route; Mercosur and Mexico call synthetic material identical-to-natural.
Is 3-Mercaptohexanol approved in the EU?
No EU FL number is on file for 3-Mercaptohexanol. It has a JECFA evaluation (JECFA 545), which the EU list draws on, but the Union List entry itself should be confirmed before EU use.
Has JECFA evaluated 3-Mercaptohexanol?
Yes. JECFA number 545, evaluated at the 53rd meeting in 1999. Conclusion: No safety concern at current levels of intake when used as a flavouring agent.
What does 3-Mercaptohexanol smell and taste like, and where is it used?
The odor of 3-Mercaptohexanol is garlic, onion, pungent, earthy, sulfurous. Typical uses are savory dishes, seasonings, meat products and sauces.
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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 3-MERCAPTOHEXANOL under CAS 51755-83-0 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.