Compounds · Aldehydes · Phenylpropanoid pathway
Cinnamaldehyde
Also known as Cinnamal · 3-Phenyl-2-propenal — an analysis may use any of these names
Cinnamon bark, hot sweetness, almost a taste. A single molecule responsible for the whole cinnamon tree in everyone’s memory.
- CAS
- 104-55-2
- Formula
- C9H8O
- Molar mass
- 132.16
- Odour threshold
- —
- Boiling point
- ≈ 248 °C at atmospheric pressure
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: CINNAMAL.
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: Phenylpropanoid pathway — plants build them around a six-carbon aromatic ring.
Why it sits where it does
An aromatic aldehyde with a conjugated double bond linked to the benzene ring. A flat, stable structure, boiling at around 248 degrees.
Where else you meet it
Cinnamon bark is almost its only source. The synthetic version is widely used in confectionery.