To begin, one must appreciate the unique origin of pubic hair. Unlike breast development, which is driven primarily by estrogens from the ovaries, the growth of pubic hair is an process. Androgens are often mislabeled as exclusively “male” hormones, but they are produced in both sexes, albeit in different quantities and with distinct functions. In females, the ovaries and the adrenal glands both produce androgens. However, the critical source for the initiation of pubarche (the onset of pubic hair growth) is the adrenal gland .

This local conversion explains a crucial clinical phenomenon: why females with complete androgen insensitivity syndrome (CAIS), who have functional androgen receptors, do not develop pubic hair despite having normal or high testosterone levels. Their bodies produce androgens, and the 5-alpha-reductase enzyme works, but the receptor cannot bind DHT. Consequently, the genetic signal is never received. Conversely, females with a deficiency of 5-alpha-reductase will have scant pubic hair, as they cannot amplify the weak testosterone signal into the powerful DHT signal. These examples prove that the “cause” is not simply the presence of an androgen, but the successful completion of a cascade: adrenal secretion of DHEA-S → peripheral conversion to testosterone → local amplification to DHT → functional androgen receptor activation.

The transition from childhood to sexual maturity is one of the most profound biological transformations in the human lifespan. For females, this journey, known as female puberty, is characterized by a cascade of physical changes: thelarche (breast development), the adolescent growth spurt, menarche (the first menstrual period), and the appearance of pubic and axillary hair. While breasts and menstruation often dominate the popular narrative of female puberty, the growth of pubic hair is a significant and universal landmark. It serves as a visible, external sign of internal endocrine shifts. The question, “What hormone causes pubic hair growth in females?” seems straightforward, but the answer is a fascinating story of biochemical conversion, cellular specificity, and synergistic action. The direct agents are a class of hormones called androgens , specifically dehydroepiandrosterone (DHEA) , its sulfate (DHEA-S), and the more potent testosterone . However, the master conductor of this process is not an androgen at all, but the adrenal-stimulating hormone, ACTH . Understanding this hierarchy reveals a nuanced picture where the “cause” is a multi-layered endocrine axis, not a single chemical messenger.