Tea tree oil (CAS 68647-73-4) — Green Top to middle Note Fragrance Ingredient
Tea tree oil
CAS 68647-73-4
What Is Tea tree oil?
Tea tree oil is a potent essential oil extracted from the leaves of the Australian Melaleuca alternifolia plant. People encounter it in antiseptic creams, natural cleaning products, and aromatherapy blends. Its sharp, medicinal aroma is instantly recognizable in first aid products. This oil matters because it’s one of nature’s most powerful antimicrobial agents, used for centuries by Indigenous Australians. Modern research confirms its efficacy against bacteria, fungi, and even some viruses, making it a staple in natural medicine cabinets worldwide.
Safety Profile
USE WITH AWARENESSWhat Does Tea tree oil Smell Like?
Tea tree oil bursts with an intensely medicinal, camphoraceous punch – imagine crushed eucalyptus leaves mixed with turpentine and fresh bandages. The initial sharpness carries a slightly sweet, nutty undertone that emerges as the top notes evaporate. Over hours, it settles into a dry, woody-herbal character with lingering antiseptic freshness. In dilution, hidden citrusy facets appear, reminiscent of crushed lime leaves. The scent profile is persistently clean but never soapy, maintaining its therapeutic character throughout evaporation.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used for its invigorating medicinal quality in this health-focused fragrance, tea tree oil adds an antiseptic crispness that complements the citrus and spice notes, creating a ‘feel-good’ aromatic effect.
The oil’s sharp freshness cuts through mint’s sweetness in this shower gel, delivering an intense wake-up call while providing actual antimicrobial benefits for blemish-prone skin.
Chemistry, Properties & Perfumer Guide
The Chemistry
Tea tree oil is a complex mixture of terpenes, primarily terpinen-4-ol (up to 40%), γ-terpinene (20%), and α-terpinene (10%). These monoterpenes are biosynthesized in the plant’s leaves as defense compounds. The oil’s antimicrobial activity correlates with terpinen-4-ol concentration, while 1,8-cineole content (when present) contributes to respiratory effects. Commercial production involves steam distillation of fresh leaves and terminal branches, with chemotypes varying by region. The oil’s composition is strictly regulated by ISO 4730 standards to ensure therapeutic quality.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Density | 0.885-0.906 g/cm³ |
| Refractive Index | 1.475-1.482 |
| Optical Rotation | +5° to +15° |
| Solubility | Soluble in alcohol, insoluble in water |
Key Constituent Properties
| Constituent | CAS | MW | BP °C | XLogP | Vapor P. |
|---|---|---|---|---|---|
| Terpinen-4-ol | 562-74-3 | 154.25 | 209-210°C | 2.7 | 0.16 mmHg |
| γ-Terpinene | 99-85-4 | 136.23 | 183°C | 3.9 | 1.3 mmHg |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Cosmetics | 0.1-1% | Up to 5% | For antimicrobial claims |
| Aromatherapy | 1-5% | Up to 10% | Diluted in carrier oils |
| Household Cleaners | 0.5-2% | Up to 5% | Surface disinfectants |
Classic Accords
Tip: Balance tea tree’s harshness with rounder notes like lavender or sweet orange to create more wearable therapeutic fragrances.
Alternatives & Comparisons
Similar medicinal properties with a gentler, fruitier aroma profile. Contains higher 1,8-cineole content making it preferable for respiratory applications.
Another Melaleuca species oil with comparable antimicrobial action but stronger camphoraceous notes. Useful when more pronounced respiratory effects are desired.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted by IFRA, but recommended maximum 5% in leave-on skin products due to sensitization potential. Always follow ISO 4730 standards for composition.
EU Allergen Declaration
Contains several potential allergens including limonene and terpinolene at varying concentrations. Must be declared if present above 0.01% in leave-on products.
GHS Classification
RIFM Assessment
RIFM assessment confirms safe use at current levels when properly diluted. Not recommended for undiluted skin application due to irritation potential.
Sustainability
Tea tree is a fast-growing crop requiring minimal pesticides, making it relatively sustainable. However, increasing global demand has led to concerns about monoculture practices in Australia. Some producers now implement regenerative farming techniques. Synthetic alternatives exist but lack the oil’s full spectrum of bioactive compounds. Responsible sourcing programs certify ethical labor practices and environmental stewardship.
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References
- Carson et al. (2006). Melaleuca alternifolia (Tea Tree) Oil: a Review of Antimicrobial and Other Medicinal Properties. Clinical Microbiology Reviews. PMID 16418522
- ISO 4730:2017. Oil of Melaleuca, terpinen-4-ol type (Tea Tree oil). ISO Standard
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 68647-73-4Odor & Flavor
| M. alternifolia (Maiden and Betche) Cheel is an evergreen Australian native tree species commonly referred to as a “paperbark” or “tea tree.” Its distribution range extends throughout northern NSW into southern Queensland. Tea tree commonly inhabits at permanent watercourses, swamp flats and springs. It is the major source of Australian tea tree oil, an economically significant, commercial product with unique antimicrobial and organoleptic properties. Long established as an antimicrobial/disinfectant, M. alternifolia oil has warm, spicy characteristics making it a desirable flavoring agent.📖 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.
