Gamma-Terpinene (CAS 99-85-4) — Citrus Top Note Fragrance Ingredient
Gamma-Terpinene
CAS 99-85-4
What Is Gamma-Terpinene?
Gamma-Terpinene is a naturally occurring terpene found in citrus oils and many herbs like oregano and marjoram. You’ll encounter it in household cleaners, citrus-scented products, and some perfumes where it adds a fresh, herbaceous lift. This molecule matters because it’s a key building block in fragrance chemistry, contributing to the bright, clean character of many citrus and herbal compositions while being generally safe for consumer use.
Safety Profile
GENERALLY SAFEWhat Does Gamma-Terpinene Smell Like?
Gamma-Terpinene bursts with a crisp, herbaceous aroma reminiscent of crushed citrus leaves and fresh oregano. The initial impression is sharply green with peppery undertones, evolving into a cleaner, pine-like character as it dries. Unlike its citrusy cousin limonene, gamma-terpinene carries more woody-herbal depth while maintaining excellent diffusion. In drydown, it leaves a subtle earthy-resinous trail that blends beautifully with woody notes.
Scent Profile
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used as part of the citrus-herbal top note accord, contributing to the fragrance’s signature freshness without overpowering the delicate citrus bouquet.
Provides naturalistic herbaceous lift to the citrus top notes, enhancing the classic cologne’s brightness and longevity.
Accents the blood orange note with green, sappy facets that make the citrus accord smell freshly peeled rather than candied.
2D Molecular Structure
SMILES: CC(C)C1=CCC(C)=CC1
Chemistry, Properties & Perfumer Guide
The Chemistry
Gamma-Terpinene is a monocyclic monoterpene hydrocarbon (C10H16) belonging to the p-menthadiene class. It occurs naturally as a minor component (1-5%) in citrus peel oils and Mediterranean herbs. Industrially produced via fractional distillation of citrus oils or isomerization of other terpenes. The molecule’s reactivity makes it prone to oxidation, forming p-cymene and other aromatic compounds. Unlike alpha-terpinene, gamma-terpinene lacks significant conjugation, giving it different photochemical behavior.
Physical & Chemical Properties
| Boiling Point | 183 °C |
|---|---|
| Density | 0.849 g/cm³ |
| Refractive Index | 1.474 |
| Flash Point | 48 °C |
| Vapor Pressure | 1.3 mmHg at 25°C |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-3% | Up to 5% | Citrus/herbal accent |
| Household Cleaners | 1-5% | Up to 10% | Freshness booster |
| Functional Fragrances | 0.1-2% | Up to 3% | Green modifier |
Classic Accords
Tip: Stabilize with antioxidants like BHT to prevent oxidation during storage.
Alternatives & Comparisons
For brighter citrus character with less herbal depth.
When more aromatic, tea-like qualities are desired.
For floral-woody nuances in place of herbal aspects.
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 restrictions under current IFRA standards.
GHS Classification
RIFM Assessment
RIFM evaluation confirms safe use at current levels in fragrance applications.
Sustainability
Most gamma-terpinene is derived as a byproduct of citrus oil processing, making efficient use of agricultural waste. Synthetic production via terpene isomerization offers consistent quality without seasonal variation. Both routes have relatively low environmental impact compared to many fragrance ingredients.
Explore Gamma-Terpinene
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References
- Burdock, G.A. (2010). Fenaroli’s Handbook of Flavor Ingredients. CRC Press. ISBN 9781439837508
- PubChem Compound Summary for CID 7461 PubChem 7461
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Mar 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID6041210
Physical Properties
| Molecular Weight | 136.238 g/mol🔬 EPA CompTox |
| Density | 0.847 g/cm^3🔬 EPA CTX |
| Boiling Point | 182.16 °C🔬 EPA CTX |
| Melting Point | -13.517 °C🔬 EPA CTX |
| Flash Point | 51.55 °C🔬 EPA CTX |
| Refractive Index | 1.476 Dimensionless📊 OPERA |
| Molar Volume | 161.128 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 4.6 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 4.299 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 4.299 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 4.32 Log10 unitless📊 OPERA |
| Water Solubility | 0 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0.023 atm-m3/mole🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 29.282 mmHg🔬 EPA CTX |
| Viscosity | 1.063 cP📊 OPERA |
| Surface Tension | 26.117 dyn/cm📊 OPERA |
| Thermal Conductivity | 119.244 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 0 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 0 count💻 Computed |
| Rotatable Bonds | 1 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 45.442 cm^3/mol📊 OPERA |
| Polarizability | 18.015 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.
