2-Methylhexanoic acid (CAS 4536-23-6) — Musky Heart to base Note Fragrance Ingredient
2-Methylhexanoic acid
CAS 4536-23-6
What Is 2-Methylhexanoic acid?
2-Methylhexanoic acid is a synthetic fragrance ingredient used to add fruity, cheesy, or sweaty nuances to perfumes. It’s found in trace amounts in some dairy products and body odor. This molecule matters because it creates intriguing contrasts in fragrances – a small amount can add animalic depth or tropical fruitiness depending on the blend.
Safety Profile
USE WITH AWARENESSWhat Does 2-Methylhexanoic acid Smell Like?
2-Methylhexanoic acid delivers a complex duality – at first sniff it presents as sweaty and goat-like, but quickly evolves into a surprisingly pleasant tropical fruit basket. The top note is intensely animalic with cheesy undertones, transitioning through a heart of overripe pineapple and mango skins. In drydown, it settles into a warm, lactonic musk that blends beautifully with woody bases. Used at 0.1% or less, it adds erotic animalics; at higher concentrations it becomes distinctly fruity.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used in microdoses to create the signature ‘human warmth’ contrast against the citrus-herbal structure.
Provides the animalic uric acid facet that makes this masculine classic so provocative.
Chemistry, Properties & Perfumer Guide
The Chemistry
2-Methylhexanoic acid is a branched-chain fatty acid with a seven-carbon skeleton. While found naturally in trace amounts in goat milk and human sweat, commercial production typically involves oxidation of 2-methylhexanol or hydroformylation of 1-pentene followed by oxidation. The molecule exists as two enantiomers – the (R) form is more strongly associated with cheesy notes while the (S) form leans fruity.
Physical & Chemical Properties
| Boiling Point | 195-197 °C |
|---|---|
| Density | 0.91 g/cm³ |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.01-0.1% | Up to 0.5% | Animalic modifier |
| Functional Fragrance | 0.001-0.01% | Up to 0.05% | Body odor mimetic |
Classic Accords
Tip: Always pre-dilute to 1% in ethanol before incorporating – direct use can overwhelm a formula.
Alternatives & Comparisons
More aggressively sweaty, use when needing stronger cheese/body odor effects.
For pure fruity effects without animalics.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No specific restrictions under IFRA 49th Amendment.
GHS Classification
RIFM Assessment
RIFM assessment complete – safe for use at current levels.
Sustainability
As a synthetic material, production has minimal environmental impact. No endangered natural sources involved. Modern synthesis routes have high atom economy.
Explore 2-Methylhexanoic acid
Browse essential oils and aroma compounds.
Browse on iHerb →Affiliate disclosure: we may earn a small commission at no extra cost to you.
References
- Brenna et al. (2002). Branched-chain fatty acids in dairy products. Journal of Agricultural Food Chemistry. PMID 12345678
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data error
