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What Does Testosterone Do To Your Body? (Science-Based)

Tyler Sellers
Published by Tyler Sellers
Fact checked by Donald Christman, BHSc FACT CHECKED
Last updated: February 16, 2022

Many people suffer from either low or high testosterone. If you’re one of them, it’s crucial that you know what testosterone does and how it affects you.

Just consider that testosterone levels can even determine your behavior. That’s how important they are.

To help you understand these effects, I’ve spent hours researching what science says about the importance of testosterone. Here are my findings.

Summary Of Key Findings

  • Testosterone plays an important role in the physical and mental development of men and women.
  • High and low testosterone may lead to side effects related to bodily functions, behavior, and physical appearance.
  • Levels of testosterone should be established with a blood test and treated accordingly.

Testosterone’s Role: Men

man with hairy beard and paper cut outs of sperm

Testosterone is often called the male sex hormone, which already tells us a lot about how vital it is for men.

It plays a crucial role in many processes and bodily functions in the male body [1, 2]:

  • Growth of the penis and testes
  • Growth of facial, pubic, and body hair
  • Deepening of the voice
  • Balding in later life
  • Muscle growth and strength
  • Sperm production
  • Red blood cell production
  • Fat distribution
  • Bone growth and strength
  • Spatial intelligence
  • Raises self-esteem
  • Behavior (stimulates aggression, dominance, competitiveness)
  • Sexual arousal and libido

As you can see, testosterone is responsible for the development of typically male characteristics, like deep voice, facial hair, and prominent muscles.

Men also wouldn’t be able to have children since they wouldn’t produce sperm without testosterone.

So, testosterone is crucial for men in many ways, but it plays an important role in women’s bodies, too.

Testosterone’s Role: Women

woman with flexing arms and a woman in sexy pose

Women’s bodies produce only 1/10 to 1/20 of the testosterone levels that we’d find in men [3]. However, that doesn’t mean that testosterone doesn’t affect them.

These are all the ways in which testosterone affects women [4, 5]:

  • Increases bone growth and strength
  • Boosts spatial intelligence
  • Raises self-esteem
  • Influences behavior (stimulates aggression, dominance, competitiveness)
  • Increases sexual arousal and libido

In fact, these are all the ways in which testosterone affects both genders and not just women.

We already know that women with higher testosterone levels can develop typically male physical traits, such as facial hair [6].

But the same may also be true for behavioral traits. For example, research shows that hypogonadal men have a lower spatial ability compared to the control group and men who acquired the condition after puberty [7].

That might explain why men, in general, tend to outperform women in spatial ability [8].

Thus, it’s possible that women with higher T levels could have a better spatial ability than women with lower levels. But more research is needed on that topic.

Symptoms of Low Testosterone

man looking at his brief with magnifying glass

Low testosterone may occur as a result of a particular condition. But it’s mainly caused by aging. Most men start experiencing a gradual decline in T after the age of 30 [9].

If you suffer from low testosterone, you’ll first notice these early symptoms:

  • Decreased sex drive
  • Erectile dysfunction
  • Reduced sperm production
  • Enlarged or tender breasts

Over time, low testosterone can lead to other side effects. It may weaken the bones, decrease muscles, or even cause infertility [10].

Also, testosterone deficiency may delay the development of young boys. If a boy suffers from low testosterone levels before or during puberty, he may not experience masculinization [11].

For example, his voice might stay the same instead of deepening; he might be unable to grow facial hair, etc.

Symptoms of High Testosterone

Too much testosterone can cause so-called precocious puberty, i.e., early puberty in young boys [12].

High testosterone levels can also cause many other side effects at later stages in life too [13]:

  • Blood clots
  • Headaches
  • Insomnia
  • Liver disease
  • Acne
  • Increased appetite and weight gain
  • High blood pressure, high cholesterol, and an increased risk of heart attack
  • Lower sperm count, testicle shrinkage, and even impotence — which may also be caused by testosterone deficiency

In addition to these side effects, high levels of testosterone may also lead to behavioral and mood changes. A person may experience mood swings, irritability, or even delusions [14].

High testosterone levels may cause adverse side effects in women, too. For example, women can experience [15]:

  • Deepening of the voice
  • Frontal balding
  • Increased muscle mass
  • Acne
  • Enlarged clitoris
  • Infertility

In other words, high testosterone levels may lead to losing typical feminine characteristics in women.

What Are Your Testosterone Levels?

stack of blood vials

You can establish whether you have high, low, or normal testosterone levels by ordering a blood test through your GP.

However, your first test may not accurately assess your testosterone levels because they fluctuate during the day.

The best way to ensure your results are accurate is to undergo testing at least twice.

It’s also advised that blood samples be drawn around 10 AM [16]. That’s when testosterone levels tend to be at their highest for most people.

He also emphasizes the importance of your doctor examining and talking to you before he schedules testing:

“As always, the patient should be examined for gynecomastia, hair loss, size of testicles, and for masses. He should be asked about his sleep patterns, as well. For example, a person who works at night shouldn’t have his testosterone checked in the morning.” -  Clifton Jackness, MD, attending physician at Lenox Hill Hospital and The Mount Sinai Medical Center in New York City

So, it’s up to your doctor to determine the best time for you to be tested for testosterone. Also, he’s the one who should establish whether you should get tested at all based on your symptoms.

Once you’ve been tested, your doctor might determine that you have high or low testosterone.

If so, he’ll go on to prescribe you an appropriate treatment.

For example, he might prescribe testosterone replacement therapy (TRT) if you have a severe testosterone deficiency. If you only have a mild deficiency, your doctor may only advise you to take natural testosterone boosters.

Testosterone Performs Many Crucial Functions

Normal testosterone levels are essential for both men and women. Testosterone affects our behavior, physical appearance, and bodily functions.

That’s why I suggest you consult with your doctor if you notice any symptoms of either high or low testosterone.

It’s best to start treating unhealthy T levels as soon as possible.


References:

  1. https://www.nih.gov/news-events/nih-research-matters/understanding-how-testosterone-affects-men
  2. https://www.healthline.com/health/low-testosterone/effects-on-body 
  3. https://www.healthline.com/health/womens-health/do-women-have-testosterone
  4. https://www.sciencedaily.com/releases/2013/02/130219121345.htm 
  5. https://www.healthline.com/health/low-testosterone/effects-on-body#Central-Nervous-System 
  6. https://www.mayoclinic.org/diseases-conditions/hirsutism/symptoms-causes/syc-20354935
  7. https://thepsychologist.bps.org.uk/volume-22/edition-1/testosterone-and-male-behaviours
  8. https://www.frontiersin.org/articles/10.3389/fnbeh.2019.00128/full 
  9. https://www.webmd.com/men/features/low-testosterone-explained-how-do-you-know-when-levels-are-too-low
  10. https://www.hormone.org/your-health-and-hormones/glands-and-hormones-a-to-z/hormones/testosterone 
  11. https://www.iomcworld.org/medical-journals/testosterone-41916.html 
  12. https://kidshealth.org/en/parents/test-testosterone.html
  13. https://www.health.harvard.edu/drugs-and-medications/testosterone--what-it-does-and-doesnt-do 
  14. https://www.dbsalliance.org/education/ask-the-doc/can-going-on-or-off-hormones-cause-mood-swings-or-a-manic-episode/ 
  15. https://www.webmd.com/women/guide/normal-testosterone-and-estrogen-levels-in-women 
  16. https://www.webmd.com/men/guide/testosterone-replacement-therapy-is-it-right-for-you 
  17. https://www.medpagetoday.com/resource-centers/hypogonadism/expert-interview-clifton-jackness-md-important-considerations-testosterone-screening/1085 
  18. https://flo.health/menstrual-cycle/health/symptoms-and-diseases/high-testosterone-in-women
  19. https://www.medicalnewstoday.com/articles/signs-of-high-testosterone#treatment

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