Compounds · Monoterpenes · Terpenoid pathway
Terpinolene
Lightly sweet, piney, with a slight floral note. Softer than the other monoterpenes.
- CAS
- 586-62-9
- Formula
- C10H16
- Molar mass
- 136.23
- Odour threshold
- 200 ppbin water
- Boiling point
- ≈ 186 °C at atmospheric pressure
The two axes are 46 points apart. Volatility tells you whether the compound leaves a surface early or late; the threshold tells you how much of it the nose needs before it notices. When the two sit this far apart, they explain things the percentages on an analysis cannot explain on their own.
Must be declared on the label
This compound was added by Regulation (EU) 2023/1545 to the list of allergens that must be declared individually on cosmetic labels in the European Union. Name to use on the label: TERPINOLENE.
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
High, similar to limonene.
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
Its double bond outside the ring makes the molecule less symmetrical, and that slightly lowers its vapour pressure compared with limonene.
Where else you meet it
Pine, rosemary, apple, and many cannabis varieties. Usually present at under a few per cent, but it contributes clearly to the sweet note.