It’s down to differences in the chemical composition of infant and teenage body odour, according to findings newly published in Communications Chemistry.
Researchers compared the chemical composition of body odour samples from 18 infants and 18 teenagers. Samples were collected from cotton pads sewn into the armpits of clothing worn by the participants for one night. The participants avoided strongly flavoured foods and perfumed products for 48 hours before the study.
The authors found that although the chemical composition of body odour was similar in both groups, those collected from teenagers contained higher levels of some carboxylic acids. They describe the odours of the carboxylic acids as "cheesy", "fruity and dried plum-like", "musty, coriander-like, and fatty", "goat-like", "wax-like and soapy", and "earthy, grassy, and green bell pepper-like". The authors also identified two steroids in samples from teenagers, which they report smell of "sweat, urine, and musk" and "sandalwood and musk". A ketone with a "violet-like" smell, and an unknown odour described as "soap- and perfume-like" was found at higher levels in infant body odour samples, compared to teenage samples.
The authors speculate that the absence of unpleasant smelling steroids together with lower levels of carboxylic acids in infant body odour samples could contribute to them being typically rated as more pleasantly scented.
