![Skeletal formula of Fenchone (1,3,3-Trimethylbicyclo[2.2.1]heptan-2-one), C10H16O, drawn from PubChem's 2D record. Stereochemistry is not shown.](/lab/materials/img/fenchone-512.1c61bdbb4f.webp)
In short
Fenchone is a bicyclic monoterpene ketone found in fennel and thuja. It has a camphoraceous, herbal odour with a bitter-fennel character.
What Fenchone smells like
Fenchone has a warm-camphoraceous, powerful and diffusive, basically sweet odour, with a warm, somewhat burning, bitter taste and a medicinal note, in a 1969 flavour and fragrance reference quoted in a patent. A flavour database lists earthy, cedar leaf, camphor, thuja, herbal, woody and bitter. Fennel oil has the highest levels, and fenchone is used in reconstructing it; it is the marker that separates fennel from anise.
- Leading note
- Warm camphor
- Supporting facets
- Earthy, bitter
- Faint facets
- Herbal, cedar leaf
- Character
- Powerful, diffusive, warm
What makes Fenchone distinctive
The camphor inside fennel: what makes fennel greener and cooler than anise.
Where the descriptions disagree: One flavour database lists its FEMA profile as floral, unlike every other description.
How Fenchone is used
Used in fennel reconstructions and herbal, camphoraceous effects, and in flavours.
Typical role: modifier (used in small amounts to change the character of a blend).
How Fenchone differs from similar materials
- Sweet Fennel Oil
- Fennel oil is mostly sweet anethole, with fenchone giving its cool, camphor-like edge. (compared directly by a cited source)
- Camphor
- Camphor is mustier and more penetrating; fenchone is described as basically sweet, warm and earthy.
- Fenchol
- Fenchol, the corresponding alcohol, is cleaner and cooler, with pine and lime; fenchone is warmer and more earthy-bitter.
- Cedar Leaf Oil
- Cedar leaf is sharper and greener; fenchone is warmer and earthier, though both share thuja-like facets.
An asterisk marks a difference that a cited source states directly. The others compare the published descriptions of each material. Smell varies with grade, supplier and dilution; compare them side by side on blotters before substituting one for another.
Identity and classification
- Type
- Aroma chemical
- Origin
- Occurs in nature
- Odour family
- Aromatic / Woody
- Note position
- Top note
- Physical form at room temperature
- Liquid
- Also known as
- 1,3,3-Trimethylbicyclo[2.2.1]heptan-2-one
- CAS number
- 1195-79-5
- Molecular formula
- C10H16O
- Molecular weight
- 152.23 g/mol
- IUPAC name
- 1,3,3-trimethylbicyclo[2.2.1]heptan-2-one
The CAS number, formula and molecular weight are taken from PubChem compound 14525, whose own record lists this CAS number; checked 19 October 2026.
Safety and compliance
Hazard classification of the neat substance, as PubChem summarises it, read 26 October 2026. Companies notifying the ECHA C&L Inventory classify it (324 reports): H226 flammable liquid and vapor (13% of reports). 269 of the reports find it does not meet the hazard criteria. Unless it is harmonised, this is the notifiers' own classification, not a binding one.
This page is general information, not a safety assessment or a specification. Confirm identity, composition, IFRA status and allergen content from your supplier's documents for the lot you hold.
Materials it works with
-
Camphor
Aroma chemical · Aromatic / Woody — camphoraceous, medicinal, cooling
-
Fenchol
Aroma chemical · Aromatic / Citrus — camphoraceous, earthy, lime, piney
-
Anethole
Aroma chemical · Aromatic / Spicy — anise, licorice, sweet, herbal
-
Sweet Fennel Oil
Essential oil · Aromatic / Green — anise, sweet, herbal, green
Fenchone is also suggested as a partner on the pages for Cedar Leaf Oil.
Used in formulas and accords
Not currently used in any published formula.
The Formula & Accord Library lists Fenchone here as soon as a published formula, accord or base uses it.
Further reading
Questions about Fenchone
Is Fenchone natural or synthetic?
The molecule occurs in nature. Commercial Fenchone may be made by synthesis or obtained from natural sources, so check the supplier's specification if the distinction matters to you.
What is the CAS number of Fenchone?
1195-79-5. It was checked against PubChem on 19 October 2026.
Sources
- PubChem — compound 14525, checked 19 October 2026.
- PubChem — GHS classification (the ECHA C&L Inventory notifications and any harmonised EU entry), read 26 October 2026.
- US4387048 — patent quoting a 1969 flavour and fragrance reference — published literature.
- Wikipedia — Fenchone — published perfumery reference.
- FlavorDB — fenchone — odour database.
- Olfactory profile: the RUŌOD Lab team's synthesis of the published descriptions above, reviewed 21 October 2026. Evidence: more than one published description. Classification and the short description: revision 1. Descriptions of odour are judgement, not measurement.