Testosterone is the primary male sex hormone. It is secreted by the testes in men and the ovaries in women. In men, it is responsible for masculine characteristics like muscle mass, beard growth and deep voice. Men produce significantly more testosterone than women, but testosterone still has an important role to play in the health and well-being of women. High free testosterone in men and women can have significant impacts on health and behavior.
Testosterone affects bone and muscle mass, the brain, genital tissues, fat distribution, vascular health and sexual functioning in both men and women.
Role of Testosterone in Men
At puberty, the levels of testosterone rise in men and cause the development of body and facial hair, sperm, muscle mass and a deepening of the voice. Under normal circumstances, the testosterone level peaks at around age 40 and declines thereafter.
Role of Testosterone in Women
Testosterone is used as a basic structure to make the female hormone estrogen in women. Testosterone is believed to play an important role in bone and muscle strength and libido in women.
What Is Free Testosterone
The majority of testosterone in men and women is bound to a specific protein in the blood called sex hormone binding globulin (SHBG), and a small amount is bound to a blood protein called albumin. What remains unbound is called free testosterone. It is easier for free testosterone to enter cells and exert its physiological effects. Factors that reduce the amount of testosterone bound to protein will result in more free testosterone in the blood and potentially high levels of free testosterone.
High Levels of Free Testosterone in Men
High free testosterone in men can lead to mood swings and unusual aggression.
According to a study at Penn State University, high free testosterone can have a significant effect on family relationships. Professor Booth at the university said, "High testosterone individuals are more likely to drink more, smoke more and get in accidents and fights... Many of them are unemployed." Professor Booth also said that men with high free testosterone were more likely to be abusive and unfaithful in relationships and to not have good relationships with their children--although some high-testosterone men did not have these problems.
On the positive side, according to researchers at Penn State University, middle-aged men with high free testosterone have a significant advantage as men with higher testosterone are less likely to suffer from obesity, heart attacks, high blood pressure and frequent colds.
High Levels of Free Testosterone in Women
Under normal circumstances, free testosterone is higher around the middle of a woman's cycle during the time of ovulation. Some believe this is nature's way of enhancing sexual activity in order to increase the chance of conception.
Persistent high free testosterone in women can cause excessive hair growth (hirsutism), particularly on the face and chest. Hirsutism combined with irregular or absent periods, infertility and acne may indicate a condition called polycystic ovaries--and rarely, ovarian cancer. If you have these symptoms, please see your doctor. Increased testosterone may also be an indication that you have low estrogen levels.
Other problems associated with increased testosterone levels include a deepening of the voice, increased aggression and male pattern baldness. Fortunately, there are many ways of treating high testosterone if it is causing these kinds of problems for you, which you can discuss with your doctor.
The Penn State University study also suggested that women with high free testosterone might also choose more male-dominated occupations than other women.