Why some underarms produce little odor
Underarm odor is not simply the smell of sweat. Much of the familiar scent forms when skin bacteria break down compounds in secretions from apocrine glands, which are concentrated in the armpits. A variant of the gene ABCC11 can reduce the amount of odor-forming material those glands release. With less raw material for bacteria to process, an underarm may have little detectable smell.
Sweating and smelling are different
The variant does not switch off sweating altogether. Eccrine glands, found across most of the body, release the watery sweat that helps cool us; their activity is distinct from the apocrine secretions linked to underarm odor. So a person can still sweat during heat or exercise while producing little of the scent commonly associated with armpits.
The same ABCC11 variant is also associated with dry earwax, because the gene affects secretions in both the ear canal and the underarm. These traits are inherited, but the amount of odor a person notices can also depend on skin bacteria and other everyday conditions. The practical distinction is simple: moisture and odor are related experiences, not the same biological process.
