Compounds · Aldehydes · Phenylpropanoid pathway
Vanillin
Also known as 4-Hydroxy-3-methoxybenzaldehyde — an analysis may use any of these names
Vanilla, warm sweetness, with a creamy note and a touch of wood.
- CAS
- 121-33-5
- Formula
- C8H8O3
- Molar mass
- 152.15
- Odour threshold
- 50 ppbin water
- Boiling point
- ≈ 285 °C at atmospheric pressure
The two axes are 31 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: VANILLIN.
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.
About the threshold figure
Moderate. Sources vary widely, from a few dozen to a few hundred parts per billion.
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 aromatic ring carrying an aldehyde, a hydroxyl and a methoxy group — three polar groups on a small molecule, so it boils very high and lasts a very long time.
Where else you meet it
Vanilla pods, white benzoin, charred oak, and almost every industrial sweet baked good.