Hair growth hormones are generally considered to be male-dominant androgens such as testosterone and androsterone, which are steroids produced naturally in the body. Hormones are secreted by the endocrine glands, but can also be manufactured synthetically. Both male and female bodies produce androgens, but they have a more dominant expression in males.
Hirsutism, the process of excessive hair growth in women, is usually caused by the conversion of weak androgens into stronger ones for a variety of physiological reasons. By contrast, when testosterone is converted in the male body to dihydrotestosterone (DHT), which is another form of hormone, it can lead to hair loss in men. The most prominent example of DHT’s role among hair growth hormones is that it results in the expression of male pattern baldness.
Female hormones such as estrogen have the opposite effect on hair growth, suppressing it. Both estrogen and testosterone are commonly referred to as “sex” hormones because they trigger sexual characteristics in men and women during puberty and beyond. In the case of women, estrogen reduces the production of body hair and facial hair, while at the same time acting in the opposite role of protecting women from developing male pattern baldness in later years. As women age, however, the concentration of estrogen in the body tends to fall, which can lead to thinning of hair on the head and some limited hair growth on other parts of the body. Menopause and pre-menopause are key times at which estrogen levels may fall, but not all changes in body hair can be traced to hormonal imbalances.
Hormones can play complicated roles in the body, being responsible for promoting and suppressing the same condition depending on the circumstances. The hair growth hormones also tend to be a catch-all form of blame for hair growth or suppression, when such conditions as thyroid problems and health issues like infections and recently-contracted diseases can also affect hair growth. Baldness in men, for instance, is strongly linked to genetic factors in certain segments of the population. Genes on the X chromosome in men in proximity to androgen receptor genes act as a key trigger for hair loss.
These well known hair growth hormones also serve other key functions in the body. Testosterone, present in both men and women, is a necessary component of healthy reproductive function. Progesterone, which is a key hormone in the uterus of pregnant women, is also linked to hair growth changes. DHT, which is the primary hormone responsible for hair loss in men, is also linked to prostate health, and its imbalance in the male body can result in prostate cancer.