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IUPAC name Non-2-enal
CAS number 2463-53-8,
18829-56-6 (trans)
60784-31-8 (cis)
Molecular formula C9H16O
Molar mass 140.22
Appearance Clear, colorless liquid
Boiling point

55-60 °C at 0.30 mmHg

MSDS External MSDS
EU classification Irritant (XI)
NFPA 704
R-phrases R38
S-phrases S24/25 S37 S45 S28
Flash point 79 °C
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

2-Nonenal is an unsaturated aldehyde which some research has associated with human body odor alterations during aging.

In the April 2001 issue of the Journal of Investigative Dermatology, Shinichiro Haze et al published an article entitled: "2-Nonenal, Newly Found in Human Body Odor Tends to Increase with Aging". [1]

In this article they reported on their work which involved the analysis of body odor components collected via headspace gas chromatography/mass spectrometry, from shirts worn for 3 days by subjects between the ages of 26 and 75. They found that the concentration of many components of body odor were unaffected by age. However, they did find that the concentration of 2-nonenal tended to increase with the age of the subjects. Furthermore, they determined that that 2-nonenal is generated by the oxidative degradation of omega-7 unsaturated fatty acids, such as palmitoleic acid and vaccenic acid, found on the skin surface.

They analyzed concentrations of various lipids on the skin surface by collecting samples in a gauze pad sewn into the shirts and then extracting the lipids with a hexane solvent. The article reported that concentrations of omega-10 fatty acids such as sapienic acid showed no change with age. However, concentrations of omega-7 fatty acids do increase with age.

2-Nonenal has an unpleasant greasy and grassy odor. Because of these findings, some observers have concluded that Haze's team has identified the cause of the phenomenon commonly known as "old lady smell", "old man smell" or "old person smell", a meme found in pop culture relating to an odor that is characteristically associated with the elderly.[2]


  1. ^ S. Haze, Y. Gozu, S. Nakamura, Y. Kohno, K. Sawano, H. Ohta and K. Yamazaki (2001). "2-Nonenal Newly Found in Human Body Odor Tends to Increase with Aging". Journal of Investigative Dermatology 116 (4): 520-524. doi:10.1046/j.0022-202x.2001.01287.x.
  2. ^ What causes "old lady smell"?
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "2-Nonenal". A list of authors is available in Wikipedia.
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