Flavor ingredient regulatory record
2-Mercapto-3-butanol
2-Mercapto-3-butanol is a thiol in the sulfur family, FEMA GRAS under FEMA number 3502 (CAS 37887-04-0). Its odor is pungent, sulfurous, onion, garlic, earthy.
- FEMA
- 3502
- CAS
- 37887-04-0
- JECFA
- 546
- EU FL
- 12.024
- Formula
- C4H10OS
- EC
- 253-701-0
GRAS status: FEMA GRAS, publication 10. Recorded by FDA in the Substances Added to Food inventory under CAS 54812-86-1.
Structure
Identity
Also known as: 2-Butanol, 3-mercapto-, (2R,3S)-rel-, 2-Butanol, 3-mercapto-, (R*,S*)-, rel-(2R,3S)-3-Mercapto-2-butanol, rel-(2r,3s)-3-mercapto-2-butanol, (2r,3s)-3-mercaptobutan-2-ol, (2r,3s)-3-sulfanylbutan-2-ol, rel-(2r,3s)-3-mercaptobutan-2-ol, 3-mercapto-2-butanol,(2r,3s)-, 2-butanol, 3-mercapto-, (2r,3s)-, as-79823.
Can 2-Mercapto-3-butanol be labeled natural?
Since 2-Mercapto-3-butanol is found in nature, US labeling follows how it was obtained: natural flavor from a natural source and a natural process, artificial when 2-Mercapto-3-butanol is synthesized. The EU and UK follow the same logic without a middle class; Mercosur and Mexico label synthetic 2-Mercapto-3-butanol 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
2-Mercapto-3-butanol is FEMA GRAS under FEMA number 3502. 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 12.024, Annex I Part A under Regulation (EC) 1334/2008, evaluation status approved (JECFA). The UK retains the same list.
JECFA (WHO / FAO)
JECFA number 546, 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.
Odor and taste
Odor: Pungent, sulfurous, onion, garlic, earthy.
Where it is used
2-Mercapto-3-butanol is used in savory dishes, seasoning, sauces and snacks, typically as a sulfur note.
Structurally similar flavor ingredients
Flavor ingredients with a GRAS determination closest to 2-Mercapto-3-butanol by structure. Whether one can replace it is a sensory and regulatory call; the reformulation tool works that through.
| Material | FEMA | Similarity | Occurrence |
|---|---|---|---|
| 3-Methyl-2-butanol | 3703 | 87% | In nature |
More thiols in this index
2-Mercaptopropionic acid · Furfuryl isopropyl sulfide · 4-Mercapto-4-methyl-2-hexanone · bis-(2-Methyl-3-furyl) tetrasulfide · 2-Methylthiophene · 3-(Methylthio)propylamine
2-Mercapto-3-butanol FAQ
Does 2-Mercapto-3-butanol have FEMA GRAS status?
2-Mercapto-3-butanol holds FEMA GRAS status under FEMA number 3502. It is also codified at 21 CFR 172.515.
How do I cite 2-Mercapto-3-butanol by FEMA or CAS number?
Cite 2-Mercapto-3-butanol as FEMA 3502 or CAS 37887-04-0; both point to the same entry. FEMA files it in the sulfur flavor category.
Can 2-Mercapto-3-butanol be labeled a natural flavor?
2-Mercapto-3-butanol occurs in nature, so the label depends on the route: 2-Mercapto-3-butanol won from a natural source by a physical, enzymatic or microbiological process is natural flavor in the United States, and synthesized 2-Mercapto-3-butanol is artificial. The EU and UK grant the natural claim only to that natural route; Mercosur and Mexico call synthetic material identical-to-natural.
Can 2-Mercapto-3-butanol be used in the EU and UK?
2-Mercapto-3-butanol is on the EU Union List of flavouring substances as FL 12.024 (Annex I Part A) under Regulation 1334/2008.
Has JECFA evaluated 2-Mercapto-3-butanol?
Yes. JECFA number 546, evaluated at the 53rd meeting in 1999. Conclusion: No safety concern at current levels of intake when used as a flavouring agent.
What does 2-Mercapto-3-butanol smell and taste like, and where is it used?
The odor of 2-Mercapto-3-butanol is pungent, sulfurous, onion, garlic, earthy. Typical uses are savory dishes, seasoning, sauces and snacks.
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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 2-MERCAPTO-3-BUTANOL under CAS 54812-86-1 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.