Testosterone in Men and Women

Man and woman in plank position, man with facial hair and bulkier muscles due to increased testosterone
Westend61 / Getty Images

Testosterone is an androgen hormone produced by the adrenal cortex, the testes (in men), and the ovaries (in women). It is often considered the primary male sex hormone. Testosterone stimulates the development of male secondary sex characteristics (like body hair and muscle growth) and is essential in the production of sperm. In women, among other things, testosterone helps keep bones and the reproductive system healthy and contributes to the sex drive.

Healthy males who have gone through puberty have 15 times the levels of testosterone compared to a healthy female.

Testosterone imbalances can cause infertility in men and women. Low levels of testosterone in men can cause male infertility. High testosterone levels in women are associated with female infertility.

Testosterone levels can be evaluated with blood work. This is usually part of an infertility workup in men and women.

Hormonal Supplementation

Testosterone is a potent steroid hormone whose chemical formulation is C19-H28-O2. Testosterone is also known as 17-beta-hydroxy-4-androstene-3-one.

Prescription testosterone is used to treat hypogonadism related conditions in men and delayed puberty in boys.

While off-label it might be used to treat perimenopause symptoms or a low sex drive, there are no U.S. Food and Drug Administration-approved (FDA) indications for testosterone prescription use in women.

Another area of medicine where testosterone is prescribed is for transgender men (people with a male gender identity and a female birth-assigned sex).

It is available as a gel, topical solution, a patch, an injection, a pellet (to be implanted), or oral capsule.

Brand names include Androderm, AndroGel, AndroGel Pump, Aveed, Axiron, Depo-Testosterone, First-Testosterone, First-Testosterone MC, Fortesta, Natesto, Striant, Testim, Testopel, Vogelxo, and Vogelxo Pump.

Risks of Supplementation

Too much testosterone can cause infertility in both males and females. Testosterone supplementation can also increase the risk of stroke, hypertension, accumulation of red blood cells, heart attack, leg clots, pulmonary embolus and cancer. The FDA only approves its use for hypogonadism and does not recommend its use for low testosterone use due to aging. The Endocrine Society, on the other hand, supports its possible use in older men with confirmed testosterone deficiency, aiming to achieve a low-normal level of the hormone, but only after carefully reviewing the risks and benefits.

Warning: Do not attempt to supplement testosterone on your own. There are a number of websites selling "testosterone supplements," and many are fake and even dangerous. Even if the testosterone supplement is real, it is not harmless and can worsen or cause infertility in both men and women.

Testing

If you are having your testosterone levels checked, the blood test will likely be scheduled for the morning.

There are two kinds of testosterone found in your blood:

  • Free testosterone (also known as free T) is testosterone that is not chemically bound to anything else. 
  • Bound testosterone makes up the majority of your total testosterone levels. Around 98% of the testosterone in your blood is bound to one of two proteins: albumin or sex hormone-binding globulin (SHBG). 

When you have your testosterone levels tested, your doctor will look at both your free testosterone levels and your total testosterone levels.

Your total testosterone levels include both free and bound testosterone.

Total testosterone levels vary throughout the day. In men younger than 45, levels are highest in the morning and lower towards evening. Once over the age of 45, it doesn't matter what time of day levels are checked at.

Normal ranges for testosterone partially depend on the lab and your doctor's interpretation. With that said, here are some general values.

For a male age 19 or older:

  • Testosterone total should be between 270-1070-950 nanograms per decileter (ng/dL)
  • Free testosterone should be between 50-210 pg/dL picograms per decileter (pg/dL)

For a female age 19 or older:

  • Testosterone total should be between 15-70 ng/dL
  • Free testosterone should be between 1.0-8.5 pg/dL

Testosterone Function

Development of sperm: Testosterone is essential to the production of sperm in the testes. It is a delicate balance, however. Both too little and too much testosterone can lead to low sperm counts.

Associated with what are known as secondary male characteristics: This includes facial and body hair growth, deepening of the voice, the building of muscle mass, increased size of bones, and distribution of fat in the body.

Infant boys and girls have similar levels of testosterone. It is only during puberty that boys begin to produce significantly higher levels of testosterone, leading to the development of the male secondary sex characteristics.

Women with abnormally high levels of testosterone may have problems with facial hair, male pattern balding, and infertility. High testosterone levels are also associated with acne in men and women.

Essential to the development of eggs in the ovaries: Androgens play an important role in ovarian follicle development and estrogen production. 

Sex drive (libido): The connection between testosterone and sex drive is well known. Higher levels of testosterone cause higher levels of sexual appetite.

Building muscle mass: Men are more likely to develop muscle mass than women because of their higher testosterone levels.

Pain tolerance: Testosterone may help men and women regulate pain levels.

Learning and memory, especially spatial intelligence: Testosterone aids in learning and memory. It is especially associated with spatial intelligence.

Men with abnormally low testosterone levels are at risk for learning disabilities.

Cognitive Empathy: Cognitive empathy involves being able to read another person’s emotions via their body language and facial expressions, especially change with the eyes.

Higher testosterone levels are associated with a lessened ability to read people. Women typically outperform men in tests of cognitive empathy. The theory is that lower testosterone levels are the reason women are better at this skill.

However, a new study out of the University of Toronto published in September of 2019, found that giving men testosterone did not reduce their empathy.

Disease and Disorders That Affect Testosterone Levels

When testosterone levels are abnormally low or high, it affects the overall health and wellbeing of an individual. This is true for both men and women. What can cause abnormal testosterone levels?

In men, possible causes of low testosterone include:

  • Age (after 50)
  • Being under or overweight
  • Smoking
  • Congenital or chromosomal disease, like Klinefelter syndrome (XXY) or Kallmann syndrome
  • Problems with the pituitary gland
  • Diseases involving the testicles
  • Abnormally high levels of iron
  • Chemotherapy and other cancer treatments
  • Major illness or surgery
  • Some medications and recreational drugs
  • Extremely high levels of stress

In men, possible causes of abnormally high testosterone levels include:

  • Adrenal or testicular tumors
  • Anabolic steroid abuse
  • Testosterone supplementation
  • Having physical contact with someone using a topical testosterone supplement

In women, possible causes of high testosterone include:

In women, the most common cause of low testosterone is menopause.

A Word From Verywell

Testosterone is an essential hormone for both men and women. If your levels are abnormal, your doctor will likely order more testing to investigate the cause. For those whose levels are low due to the normal effects of aging, testosterone supplementation may be an option to consider.

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Article Sources
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