Body odor or body odour, sometimes colloquially abbreviated as B.O., is the smell of bacteria growing on the body. The bacteria multiply rapidly in the presence of sweat, but sweat itself is almost completely odorless to humans.
The condition can be known medically as bromhidrosis, apocrine bromhidrosis, bromidrosis, osmidrosis, ozochrotia, fetid sweat, body smell or malodorous sweating.
Body odour can smell pleasant and specific to the individual and can be used to identify people, though this is more often done by dogs and other animals than by humans. An individual’s body odor is also influenced by diet, lifestyle, gender, genetics, health and medication.
Propionic acid (propanoic acid) is present in many sweat samples. This acid is a breakdown product of some amino acids by propionibacteria, which thrive in the ducts of adolescent and adult sebaceous glands.
Because propionic acid is chemically similar to acetic acid with similar physical characteristics including odor, body odors may be identified as having a vinegar-like smell by certain people.
Isovaleric acid (3-methyl butanoic acid) is the other source of body odor as a result of actions of the bacteria Staphylococcus epidermidis, which is also present in several strong cheese types.
Treatment
Body odor may be reduced or prevented or even aggravated by using deodorants, antiperspirants, disinfectants (e.g., triclosan), special soaps or foams with antiseptic plant extracts such as ribwort and liquorice, chlorophyllin ointments and sprays topically, and chlorophyllin supplements internally.
Although body odor is commonly associated with hygiene practices, its presentation can be affected by changes in diet.