[7] In humans, apocrine sweat glands are found only in certain locations of the body: the axillae (armpits), areola and nipples of the breast, ear canal, eyelids, wings of the nostril, perineal region, and some parts of the external genitalia.

Their apocrine glands, like those in humans, produce an odorless, oily, opaque secretion[10] that gains its characteristic odor upon bacterial decomposition.

[18][19] In hoofed animals and marsupials, apocrine glands act as the main thermoregulator, secreting watery sweat.

[9] For most mammals, however, apocrine sweat glands secrete an oily (and eventually smelly) compound that acts as a pheromone,[20] territorial marker, and warning signal.

[21] In a five-month-old human in utero, apocrine glands are distributed all over the body; after a few weeks, they exist in only restricted areas,[9] including the armpits and external genitalia.

[20] The "axillary organs", limited regions with equal numbers of apocrine and eccrine sweat glands, only exist in humans, gorillas, and chimpanzees.

[29][30] There is currently no evidence that any sweat glands vary substantially by racial group, with most studies claiming to find variation being subject to methodological flaws.