Flavor ingredient regulatory record
Phenethyl isothiocyanate
Phenethyl isothiocyanate is an isothiocyanate in the spice family, FEMA GRAS under FEMA number 4014 (CAS 2257-09-2). Its odor is pungent, mustard-like, spicy, sulfurous.
- FEMA
- 4014
- CAS
- 2257-09-2
- JECFA
- 1563
- EU FL
- 12.193
- Formula
- C9H9NS
- EC
- 218-855-5
GRAS status: FEMA GRAS, publication 20. Recorded by FDA in the Substances Added to Food inventory under CAS 2257-09-2.
Structure
Identity
Also known as: Benzene, (2-isothiocyanatoethyl)-, Isothiocyanic acid, phenethyl ester, (2-Isothiocyanatoethyl)benzene, Phenethyl mustard oil, β-Phenylethyl isothiocyanate, Phenylethyl isothiocyanate, Phenylethyl mustard oil, 2-Phenylethyl isothiocyanate, β-Phenethyl isothiocyanate, NSC 87868, JC 5411, 1-(2-Isothiocyanatoethyl)benzene.
Can Phenethyl isothiocyanate be labeled natural?
Since phenethyl isothiocyanate is found in nature, US labeling follows how it was obtained: natural flavor from a natural source and a natural process, artificial when phenethyl isothiocyanate is synthesized. 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.
- 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
Phenethyl isothiocyanate is FEMA GRAS under FEMA number 4014. 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 12.193, Annex I Part A under Regulation (EC) 1334/2008, evaluation status approved (EFSA). The UK retains the same list.
JECFA (WHO / FAO)
JECFA number 1563, evaluated at the 65th meeting in 2005. ACCEPTABLE (CONDITIONAL).
Other US flags
Not on the California Proposition 65 list.
TSCA Inventory status
A flavor ingredient is also an industrial chemical. Phenethyl isothiocyanate appears on the EPA Toxic Substances Control Act Chemical Substance Inventory under CAS 2257-09-2, where EPA names it Benzene, (2-isothiocyanatoethyl)-.
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: Pungent, mustard-like, spicy, sulfurous.
Where it is used
Phenethyl isothiocyanate is used in seasoning, condiment, snack foods and sauces, typically as a spice note.
Structurally similar flavor ingredients
Flavor ingredients with a GRAS determination closest to Phenethyl isothiocyanate by structure. Whether one can replace it is a sensory and regulatory call; the reformulation tool works that through.
| Material | FEMA | Similarity | Occurrence |
|---|---|---|---|
| Hexyl isothiocyanate | 4422 | 91% | In nature |
| 5-Hexenyl isothiocyanate | 4421 | 89% | In nature |
| Amyl isothiocyanate | 4417 | 89% | In nature |
| 4-Pentenyl isothiocyanate | 4427 | 89% | In nature |
| 3-(Methylthio)propyl isothiocyanate | 3312 | 89% | In nature |
More isothiocyanates in this index
4-Pentenyl isothiocyanate · 5-(Methylthio)pentyl isothiocyanate · 2-Butyl isothiocyanate · Isoamyl isothiocyanate · Hexyl isothiocyanate · 3-(Methylthio)propyl isothiocyanate
Phenethyl isothiocyanate FAQ
Is phenethyl isothiocyanate FEMA GRAS?
Yes. The FEMA Expert Panel lists phenethyl isothiocyanate as GRAS under FEMA number 4014. It is also codified at 21 CFR 172.515.
What are the FEMA and CAS numbers for phenethyl isothiocyanate?
Phenethyl isothiocyanate is FEMA 4014, CAS 2257-09-2. FEMA files it in the spice flavor category.
Does phenethyl isothiocyanate count as natural in the US and the EU?
Phenethyl isothiocyanate occurs in nature, so the label depends on the route: phenethyl isothiocyanate won from a natural source by a physical, enzymatic or microbiological process is natural flavor in the United States, and synthesized phenethyl isothiocyanate is artificial. The EU and UK follow the same logic without a middle class; Mercosur and Mexico label synthetic phenethyl isothiocyanate identical-to-natural.
Is phenethyl isothiocyanate on the EU Union List?
Phenethyl isothiocyanate is on the EU Union List of flavouring substances as FL 12.193 (Annex I Part A) under Regulation 1334/2008.
Has JECFA evaluated phenethyl isothiocyanate?
Yes. JECFA number 1563, evaluated at the 65th meeting in 2005. Conclusion: ACCEPTABLE (CONDITIONAL).
How is phenethyl isothiocyanate described, and where does it show up?
Flavorists describe phenethyl isothiocyanate as pungent, mustard-like, spicy, sulfurous. It is used in seasoning, condiment, snack foods 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 PHENETHYL ISOTHIOCYANATE under CAS 2257-09-2 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.