d,l-Menthol (isomer unspecified) (CAS 1490-04-06) — Green Top to middle Note Fragrance Ingredient
d,l-Menthol (isomer unspecified)
CAS 1490-04-06
What Is d,l-Menthol (isomer unspecified)?
d,l-Menthol is the cooling compound found in mint plants and many consumer products. People encounter it in toothpaste, chewing gum, cough drops, and topical pain relievers. It provides the characteristic minty freshness and cooling sensation. This versatile ingredient matters because it bridges functional benefits (cooling) with pleasant minty aromas. It’s used across personal care, food, and pharmaceuticals for its dual sensory and physiological effects.
Safety Profile
GENERALLY SAFEWhat Does d,l-Menthol (isomer unspecified) Smell Like?
d,l-Menthol delivers an intense, piercing mintiness with crystalline clarity – like inhaling crushed peppermint leaves in a winter forest. The initial burst is sharply cooling, almost medicinal, before softening into a sweeter herbal character. Unlike pure l-menthol, this racemic mixture lacks the precise directional freshness but gains broader applicability. The dry-down lingers as a clean, camphoraceous whisper with subtle woody undertones. When diluted, it creates refreshing top notes; at higher concentrations, it produces pronounced physiological cooling effects.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used for its crisp minty freshness that complements the aquatic theme, creating a bracing shower-fresh effect in the top notes.
Provides cooling contrast to the violet leaf, enhancing the fragrance’s crisp green character without overpowering the floral heart.
Adds minty brightness to balance the dense pine and oakmoss base, preventing the composition from becoming too heavy.
Used sparingly to amplify the citrus top notes with a subtle cooling effect that enhances the ‘universal water’ concept.
Key functional ingredient providing the signature invigorating mint-citrus burst that defines this aromatherapeutic fragrance.
Chemistry, Properties & Perfumer Guide
The Chemistry
d,l-Menthol is a racemic mixture of the two enantiomers of menthol (l-menthol and d-menthol), a monocyclic terpene alcohol. While l-menthol occurs naturally in mint oils, the d,l mixture is typically synthesized via hydrogenation of thymol or from pinene derivatives. The racemic form has different crystallization properties and slightly altered odor characteristics compared to pure l-menthol. Chemically, it’s a secondary alcohol with three chiral centers, but the racemic mixture lacks optical activity. The cooling effect comes from activation of TRPM8 cold receptors in sensory neurons.
Physical & Chemical Properties
| Melting Point | 36-38 °C |
|---|---|
| Boiling Point | 212 °C |
| Flash Point | 93 °C |
| Solubility | Sparingly soluble in water, freely soluble in alcohol and oils |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | For cooling mint effects |
| Functional Fragrances | 1-3% | Up to 10% | In shower gels, shaving products |
| Oral Care | 0.1-1% | Up to 2% | For mint freshness |
| Topical Analgesics | 3-10% | Up to 16% | For cooling pain relief |
Classic Accords
Tip: Use ethanol as solvent when high concentrations are needed to prevent crystallization in final products.
Alternatives & Comparisons
The natural enantiomer with stronger cooling effect and sharper mint character. Preferred when precise odor direction is needed.
Less cooling but provides similar minty-herbal notes without the crystallization issues of menthol at high concentrations.
Offers minty character with less cooling sensation, useful when the physiological effect needs to be moderated.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No IFRA restrictions. Generally recognized as safe for use in fragrances.
GHS Classification
RIFM Assessment
RIFM has evaluated menthol isomers extensively. The racemic mixture is considered safe at current usage levels.
Sustainability
Most commercial d,l-menthol is synthesized from petrochemical feedstocks, though some is derived from turpentine (a renewable resource). The synthesis route impacts environmental footprint – thymol hydrogenation is more energy-intensive than pinene routes. Biocatalytic production methods are being developed for more sustainable menthol production.
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References
- Eccles R. (1994). Menthol and related cooling compounds. Journal of Pharmacy and Pharmacology. PMID 7877319
- Bickers DR et al. (2005). A toxicologic and dermatologic assessment of cyclic and non-cyclic terpene alcohols. Food and Chemical Toxicology. PMID 16112377
- Höfer R et al. (2016). Menthol: A renewable resource for the flavor and fragrance industry. Chemistry & Biodiversity. PMID 27603324
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
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