Q: What are hormones?
A: Although there are a variety of hormones pumping through the veins of males and females at any given time, let’s keep it simple and focus on the major classifications of the hormones involved in sexual differentiation: Androgens and estrogens. Androgens is the generic term for the hormones that promote the development and functioning of the male reproductive system. Estrogens is the generic term for the hormones that stimulate functioning and maturation of the female reproductive system. Both classes of female and male hormones are present in the bodies of males and females, but in drastically different amounts.
The primary “male” hormone is testosterone. Most men produce 6-8 milligrams of testosterone (an androgen) each and every day, compared to the typical woman who produces about 0.5 milligrams daily. Females hormones, also known as estrogens, are also present in both sexes, but of course, in larger amounts for women.
Estrogens are the sex hormones that are produced mainly by a female’s ovaries that stimulate the maturation of secondary sex characteristics. Secondary sex characteristics include the growth of a female’s reproductive organs, as well as her breasts and pubic hair. Estrogens also regulate the functioning of a female’s menstrual cycle. Estrogens do not play a significant role in a female’s level of sexual desire, however, they are important in maintaining the health of the vaginal lining and elasticity, producing vaginal lubrication, and in preserving the texture and function of a woman’s breasts (i.e., lactation during and after pregnancy).
Estrogens have no known function in men. However, an unusually high level of estrogen in men may reduce sexual desire, create erectile difficulties, may produce some breast enlargement, and can result in the loss of body hair in some men. Androgens are sex hormones primarily produced by a male’s testes, but are also produced in the adrenal gland of both sexes, as well as in small amounts by the female’s ovaries.
Androgens (like testosterone) help to initiate the development of the testes and penis in the male fetus. They trigger the start of puberty and influence muscle development, the growth of facial, body and pubic hair, and cause a male’s voice to deepen. Together, all of these pubertal changes taking place in a male’s body are called secondary sex characteristics. Research has also provided evidence that pre-natal hormonal exposure influences brain development; creating some of cognitive differences among males and females, as well as being instrumental in the biological foundations of sexual orientation.
During and after puberty, androgens, specifically testosterone, play a significant role in the regulation of an individual’s sex drive. Large deficiencies of testosterone may cause a drop in sexual desire, and excessive testosterone levels may heighten sexual desire in both males and females. However, testosterone levels within the normal range have little effect on either sex’s sexual interest. An individual’s sex drive is much more likely to be influenced by psychological and emotional factors, as well as external stimuli (i.e., sights, sounds, smells, and touch).
One last hormone-fact regarding testosterone in men deserves to be mentioned. Research has found a link between high levels of testosterone and balding in men. Men with high levels of testosterone also produce large amounts of cortisol. Cortisol is a steroid (aka androgen) hormone that is released in men due to high stress levels, which in turn, has been linked to testosterone levels. Cortisol inhibits follicle growth by continually weakening the root cells of hair follicles on a man’s head. Since higher levels of testosterone in men is also related to greater athletic ability, stamina and sexual desire, it is not surprising that male-pattern balding is so prevalent throughout the world. Men with a lot of testosterone often do not find it difficult finding mates.
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Poor, V., Juricskay, S., & Telegdy, E. (2002). Urinary steroids in men with male-pattern alopecia. Journal of Biochemical & Biophysical Methods, 53(1-3), 123-131.
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