Researchers Pinpoint Why Teenagers Stink

While it doesn't take a team of scientists to determine that teens tend to smell worse than toddlers, researchers say they've pinpointed the cause of what they describe as the "less pleasant body odor of teenagers." In a study published in the journal Communications Chemistry, researchers who compared infants to teenagers say they identified two steroids that cause teens to smell of "sweat, urine, musk, and sandalwood," along with carboxylic acids with odors described as "cheesy" and "goat-like," the Guardian reports. The infants, meanwhile, had high levels of a ketone that smells like soap, flowers, and violets.

• The experiment. The researchers looked at 18 children younger than three and 18 post-puberty teens between 14 and 18 years old. After washing with odor-free products, they slept in shirts or body suits with cotton patches sewn into the armpits. The patches were analyzed for chemical compounds.

• The big difference. The two steroids that caused unpleasant smells were only present in teens because their precursors were secreted by sweat glands that aren't active before puberty, the New York Times reports. They became steroids when broken down by skin microbes. The carboxylic acids were the result of the secretion of sebum, an oily substance that protects the skin. The glands involved are dormant in children but "get very active again around puberty," says researcher Helene Loos, per Scientific American.
• Interactions with parents. The body odors of infants "are pleasant and rewarding to mothers and, as such, probably facilitate parental affection," researchers wrote. "In contrast, BOs of pubertal children are rated as less pleasant." They noted that while parents can identify the odors of their own infants, they "are unable to identify their own child" during puberty.
• The role of evolution. Psychologist Ilona Croy, a study co-author, says the pleasant scent of infants makes sense because it "facilitates bonding between parents and children." But as they become teens, "becoming smellier to mom and dad can help them foster a degree of independence," according to Scientific American.
• Goodbye to goaty smells? The Guardian notes that the findings could spur the development of deodorants better able to mask the smell of the stinky compounds.

(More body odor stories.)