Compounds · Alcohols · Terpenoid pathway
Geraniol
Also known as trans-Geraniol · Lemonol — an analysis may use any of these names
Rose, sweet, slightly waxy. More lasting than citral and carries further on the skin.
- CAS
- 106-24-1
- Formula
- C10H18O
- Molar mass
- 154.25
- Odour threshold
- 40 ppbin water
- Boiling point
- ≈ 230 °C at atmospheric pressure
For this compound the two axes sit close together. Volatility tells you whether it leaves a surface early or late; the threshold tells you how much of it the nose needs before it notices.
Must be declared on the label
This compound is on the list of allergens that must be declared individually on cosmetic labels in the European Union, as one of the 24 substances listed before Regulation 2023/1545. Name to use on the label: GERANIOL.
The declaration threshold is 0.001% in leave-on products and 0.01% in rinse-off products. This is an EU requirement — see the regulations page for why it matters beyond the EU. This is not legal advice.
Where it comes from
Biosynthetic pathway: Terpenoid pathway — plants build them from identical five-carbon blocks.
About the threshold figure
Moderate. This is the compound behind the rose note in palmarosa and geranium.
Published thresholds differ by several orders of magnitude, because of differences in measuring method, sample purity and panel. The figure here is an order of magnitude for relative comparison, not a measurement. We give it only for compounds where the literature broadly agrees — 52 of the 106 compounds in the library. The rest are left blank rather than guessed.
Why it sits where it does
An open-chain alcohol with its hydroxyl group at the end of the chain, forming good hydrogen bonds, so it boils at around 230 degrees.
Where else you meet it
Rose, geranium, lemongrass. One of the most thoroughly studied aroma molecules because of its role in the smell of rose.