Estragole (CAS 140-67-0) — Sweet Heart Note Fragrance Ingredient
Estragole
CAS 140-67-0
What Is Estragole?
Estragole is a naturally occurring aromatic compound found in tarragon, basil, and fennel. You’ll encounter its sweet, anise-like scent in herbal teas, Mediterranean cooking, and some perfumes. While pleasant, it’s one of those background notes that makes herbs smell ‘herbal’ rather than standing out on its own. This molecule matters because it’s a building block for more complex fragrances, adding a warm, spicy-herbal character that perfumers use to create depth in fougères and oriental accords.
Safety Profile
USE WITH AWARENESS
What Does Estragole Smell Like?
Estragole greets the nose with a bright, piercing sweetness reminiscent of crushed anise seeds and fresh tarragon leaves. The initial burst carries a slightly metallic sharpness that quickly mellows into a warm, herbaceous heart. As it dries down, it reveals subtle woody undertones and a faintly phenolic edge that lingers like the aftertaste of black licorice. Unlike its cousin anethole, estragole lacks the heavy candy-like sweetness, instead offering a leaner, more vegetal profile that evokes sun-warmed Mediterranean hillsides dotted with wild fennel.
Scent Profile
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
The original fougère blueprint uses estragole’s herbal facets to bridge the gap between lavender’s floralcy and coumarin’s hay-like sweetness, creating the archetypal ‘fern’ impression that defines the genre.
Estragole’s crispness amplifies the citrus top notes while its herbal depth supports the rosemary and basil, contributing to this classic’s timeless freshness.
Here estragole’s anisic qualities recreate absinthe’s narcotic herbal bouquet, blending with wormwood and spices for a dangerously addictive drydown.
The molecule’s natural occurrence in basil helps create photorealistic herbaceousness that plays against neroli’s orange blossom sweetness in this summer favorite.
Estragole’s warmth blends with amber and spices to evoke North African markets, its herbal edge cutting through the resinous richness.
2D Molecular Structure
SMILES: COC1=CC=C(CC=C)C=C1
Chemistry, Properties & Perfumer Guide
The Chemistry
Estragole (1-allyl-4-methoxybenzene) is a phenylpropene derivative in the same chemical family as eugenol and safrole. Naturally occurring as the (R)-enantiomer in plants, it’s biosynthesized from phenylalanine via the shikimate pathway. Industrial production typically involves alkylation of p-methoxyphenol with allyl chloride or isomerization of trans-anethole. The molecule’s planar structure and electron-rich aromatic ring make it highly reactive, capable of forming DNA adducts that raised safety concerns. Interestingly, oxidation of the allyl group converts estragole into anethole, explaining their closely related scent profiles.
Physical & Chemical Properties
| Boiling Point | 216 °C |
|---|---|
| Density | 0.965 g/cm³ |
| Refractive Index | 1.517-1.521 |
| Flash Point | 88 °C |
| Solubility | Insoluble in water, miscible with alcohol |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Adds herbal complexity |
| Functional Fragrance | 0.1-0.5% | Up to 1% | Herbal freshness in soaps |
| Flavorings | 10-100 ppm | Up to 500 ppm | Natural taste enhancement |
| Aromatherapy | 0.5-1% | Up to 2% | Use with caution in blends |
Classic Accords
+ Citrus + Mint = Fresh Cologne
+ Vanilla + Cinnamon = Spiced Oriental
+ Oakmoss + Patchouli = Dark Chypre
Tip: Use estragole in trace amounts with citrus top notes to prevent the blend from skewing too medicinal.
Alternatives & Comparisons
For a sweeter, more candied anise effect without estragole’s herbal edge and safety concerns.
Nearly identical chemically but often perceived as slightly greener and less sweet in comparisons.
Offers similar aromatic qualities without the allyl group’s reactivity concerns.
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
IFRA restricts estragole to 0.01% in leave-on products (Amendment 49) due to potential genotoxicity. Banned in cosmetics in the EU under Regulation 1223/2009.
GHS Classification
RIFM Assessment
RIFM recommends avoiding estragole in consumer products based on rodent carcinogenicity data, though human relevance remains debated.
Sustainability
Most commercial estragole is now synthesized rather than extracted from plants due to safety concerns. The synthetic route from guaiacol is more environmentally friendly than traditional distillation from tarragon oil, requiring less land and water resources. However, the petrochemical origin raises carbon footprint questions, prompting research into biotechnological production using engineered microorganisms.
Explore Estragole
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Industry & Science Data
References
- Smith et al. (2002). Estragole bioactivation. Chemical Research in Toxicology. PMID 12052028
- SCF (2001). Opinion on estragole. European Commission. EU SCF Report
- EMA (2014). Public statement on estragole. European Medicines Agency. EMA Report
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Mar 2026.
Ingredient Data Sheet
CAS 140-67-0Physical Properties
| Molecular Weight | 148.2 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 3.4🔬 PubChem |
| Boiling Point | 216.1 °C🔬 EPA CompTox |
| Vapor Pressure | 0.05 mmHg @ 25°C📊 OPERA |
| Flash Point | 81.1 °C🔬 EPA CompTox |
| Involatility Index | 0.0044💻 Calculated |
| log Kp (skin permeability) | -1.19💻 Calculated |
| SMILES | COC1=CC=C(C=C1)CC=C🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
| Volatility Class | Very slow💻 Calculated |
| Persistence Score | 2.4 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | herbalsweet• leffingwell |
| Functional Groups | etheralkenearomatic💻 RDKit |
| “Sweet-herbaceous Anise-Fennel type odor. Much more herbaceous than Anethole, and not as intensely sweet.”📖 Arctander | |
| Estragole has an odor reminiscent of anise with a corresponding sweet taste (differing from anethole).📖 Fenaroli | |
Flavor Notes (Arctander)
| “The taste is not nearly as sweet as that of Anethole, and not as "clean" or singular. More warm-herbaceous, complex. More widely used in flavor compositions, particularly in seasonings, dressings, condiments and meat flavors. As a modifier for Anethole it finds use in Licorice flavorings, and in sma”📖 Arctander |
Sensory Thresholds
| Odor Detection Threshold | 0.0188 ppm (n=6)📖 van Gemert |
Regulatory Status
| IFRA Listed | Yes — see IFRA Standards for category limits⚖️ IFRA 51 |
| EU Annex III | Listed (restricted)⚖️ IFRA 51 |
| FEMA Number | FEMA 2411⚖️ 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: DTXSID0020575
Physical Properties
| Molecular Weight | 148.205 g/mol🔬 EPA CompTox |
| Density | 0.964 g/cm^3🔬 EPA CTX |
| Boiling Point | 215.73 °C🔬 EPA CTX |
| Melting Point | -30.52 °C🔬 EPA CTX |
| Flash Point | 80.852 °C🔬 EPA CTX |
| Refractive Index | 1.505 Dimensionless📊 OPERA |
| Molar Volume | 157.853 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.4 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 3.079 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.079 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 4.98 Log10 unitless📊 OPERA |
| Water Solubility | 0.028 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 32.119 mmHg🔬 EPA CTX |
| Viscosity | 1.945 cP📊 OPERA |
| Surface Tension | 31.412 dyn/cm📊 OPERA |
| Thermal Conductivity | 139.164 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 9.23 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 1 count💻 Computed |
| Rotatable Bonds | 3 count💻 Computed |
| Aromatic Rings | 1 count💻 Computed |
| Molar Refractivity | 46.839 cm^3/mol📊 OPERA |
| Polarizability | 18.568 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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