The “old people smell” is actually caused by a chemical, called 2-Nonenal, that old people secrete through their skin.
Research led by Dr. Shinichiro Haze in 2001 discovered that older individuals emit a distinctive body odor compound called 2-Nonenal, which becomes prominent in people aged 40 and older. This compound results from the breakdown of omega-7 unsaturated fatty acids released by older people’s skin when exposed to air. Lipid peroxides play a role in accelerating this transformation.