Skatole (CAS 83-34-1) — fecal base Note Fragrance Ingredient
Skatole
CAS 83-34-1
What Is Skatole?
Skatole is a fragrance molecule with a dual personality. At high concentrations, it smells distinctly fecal, but at trace levels it contributes warm, floral nuances. You’ll encounter it in some perfumes and flavorings. This paradoxical ingredient matters because it demonstrates how concentration transforms perception – what’s repulsive at one level becomes desirable at another.
Safety Profile
USE WITH AWARENESSWhat Does Skatole Smell Like?
Skatole presents a fascinating olfactory paradox. Undiluted, it assaults with an intensely fecal, animalic character reminiscent of barnyards. Yet when meticulously diluted below 0.1%, it metamorphoses into a warm, sweet floral with narcotic undertones – like overripe tropical fruit dipped in honey. As a base note, it provides animalic depth that evolves into a velvety floralcy over hours. Master perfumers use it to add carnal complexity to white florals, where it behaves like a shadowy twin to jasmine absolute.
Scent Profile
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used as a counterpoint to the lush florals, skatole adds animalic warmth that transforms the composition from pretty to primal. It creates tension with the vanilla base.
Skatole contributes to the legendary animalic musk accord, providing fecal facets that make the scent feel alive and human.
2D Molecular Structure
SMILES: CC1=CNC2=C1C=CC=C2
Chemistry, Properties & Perfumer Guide
The Chemistry
Skatole (3-methylindole) is an aromatic heterocyclic compound belonging to the indole class. While found naturally in mammalian feces and some flowers like orange blossoms, commercial skatole is synthesized via Fischer indole synthesis from phenylhydrazine and propionaldehyde. The planar structure allows π-π stacking interactions that influence its odor threshold. Chirality isn’t relevant as the molecule lacks stereocenters.
Physical & Chemical Properties
| Boiling Point | 265-266 °C |
|---|---|
| Melting Point | 95 °C |
| Vapor Pressure | 0.0055 mmHg |
| XLogP | 2.6 |
| Solubility | Alcohol, benzene, chloroform |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.001-0.01% | Up to 0.1% | Animalic modifier |
| Flavorings | 0.0001-0.001 ppm | Up to 0.01 ppm | Fruity nuance |
Classic Accords
Tip: Always pre-dilute to 0.1% or below before incorporating to avoid overwhelming fecal character.
Alternatives & Comparisons
Less animalic but similar floral effects at low levels. Prefer when skatole’s fecal notes are too pronounced.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. IFRA, REACH, EU Cosmetics Regulation standards update periodically. Consult current IFRA Standards Library before formulating. Not legal or regulatory advice.
IFRA Status
No IFRA restrictions. FEMA GRAS# 3019.
GHS Classification
RIFM Assessment
RIFM evaluation confirms safe use at current levels in fragrances.
Sustainability
Synthetic production avoids animal-derived sources. Manufacturing uses standard petrochemical feedstocks with moderate environmental impact. No known ecological concerns at usage levels.
Explore Skatole
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References
- PubChem Skatole CID 6736
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Mar 2026.
Report a data errorIngredient Data Sheet
CAS 83-34-1Physical Properties
| Molecular Weight | 131.17 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 2.6🔬 PubChem |
| Boiling Point | 265 °C🔬 EPA CompTox |
| Vapor Pressure | 0.0055 mmHg @ 25°C📊 OPERA |
| Flash Point | 132 °C🔬 EPA CompTox |
| Involatility Index | 0.0005💻 Calculated |
| log Kp (skin permeability) | -1.654💻 Calculated |
| SMILES | CC1=CNC2=CC=CC=C12🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
| Volatility Class | Very slow💻 Calculated |
| Persistence Score | 3.5 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | animalicfloralfruity• leffingwell |
| Functional Groups | aromatic💻 RDKit |
| “The use of Skatole in flavors may come as a surprise to some perfumers who find it hard to believe that we can "eat" this odor. But minute traces are useful in Grape and Cheese imitation flavor, fruit complexes, Nut flavors, etc., highest in Cheese flavor. Concentrations in the end product vary from 0.01 to 1 ppm.”📖 Arctander | |
| Skatole has a characteristic putrid, fecal odor at high concentrations, becoming pleasant, sweet, warm at very low concentrations. It has a warm overripe fruity flavor below 1 ppm.📖 Fenaroli | |
Flavor Notes (Arctander)
| “The taste of Skatole is warm, overripe fruity at concentrations below 0.1 ppm, while it becomes more animal near 1 ppm. The use of Skatole in flavors may come as a surprise to some perfumers who find it hard to believe that we can "eat" this odor. But minute traces are useful in Grape and Cheese imi”📖 Arctander |
Sensory Thresholds
| Odor Detection Threshold | 0.0126 ppm (n=24)📖 van Gemert |
Regulatory Status
| FEMA Number | FEMA 3019⚖️ FEMA GRAS |
| GRAS Status | Generally Recognized as Safe⚖️ FEMA GRAS |
| IOFI Classification | Nature Identical📖 Fenaroli |
Physical data: PubChem (NIH/NLM), U.S. EPA CompTox Dashboard, EPA OPERA models, RDKit. Odor & flavor: Arctander (Perfume & Flavor Chemicals), Fenaroli's Handbook of Flavor Ingredients, Leffingwell. Thresholds: van Gemert (Compilations of Odour Threshold Values). Regulatory: IFRA Standards 51st, FEMA GRAS. Trade names: Surburg (Common Fragrance & Flavor Materials). All data compiled and cross-referenced for perfumertools.com.
Physicochemical Properties
DTXSID: DTXSID8021775
Physical Properties
| Molecular Weight | 131.178 g/mol🔬 EPA CompTox |
| Density | 1.115 g/cm^3📊 OPERA |
| Boiling Point | 265.625 °C🔬 EPA CTX |
| Melting Point | 96.084 °C🔬 EPA CTX |
| Flash Point | 132.05 °C🔬 EPA CTX |
| Refractive Index | 1.655 Dimensionless📊 OPERA |
| Molar Volume | 118.147 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 2.6 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 2.578 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 2.593 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 7.77 Log10 unitless📊 OPERA |
| Water Solubility | 0.004 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0.17 atm-m3/mole🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 0.006 mmHg🔬 EPA CTX |
| Viscosity | 4.881 cP📊 OPERA |
| Surface Tension | 46.401 dyn/cm📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 15.79 Ų💻 Computed |
| H-Bond Donors | 1 count💻 Computed |
| H-Bond Acceptors | 0 count💻 Computed |
| Rotatable Bonds | 0 count💻 Computed |
| Aromatic Rings | 2 count💻 Computed |
| Molar Refractivity | 43.353 cm^3/mol📊 OPERA |
| Polarizability | 17.187 Å^3📊 OPERA |
Data Sources:
🔬 EPA Experimental data from U.S. EPA CompTox Chemicals Dashboard & CTX APIs. 📊 OPERA Predicted using EPA's OPERA QSAR models. 💻 Computed Calculated from SMILES using RDKit.
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