Testosterone (natural, replacement): what is it and what does it do?

Men, in general, know the functions of testosterone well, as it is considered the male sex hormone. However, it has several other functions that are not only related to male characteristics, such as beard, or to sexual characteristics, such as erection.

In fact, testosterone is also naturally present in the female organism, albeit in much smaller quantities.


What is testosterone?

Testosterone is called the male sex hormone. Despite the name, women also produce testosterone, but to a lesser extent, in the same way as so-called female sex hormones ( progesterone and estrogen) are also present in men.

In men, the testicles are responsible for the production of testosterone. In women, the organs that produce the hormone are the ovaries and adrenal glands, in considerably smaller quantities than in men.

This hormone is responsible for muscle growth, for the growth of hair on the body, for the deepening of the voice in adolescence, in addition to other developments, such as sexual, being important for fertility and sexual arousal.

The hormone also influences behavior, altering risky decision making and is a type of anabolic steroid.

Testosterone in women (female): what does it do?

Testosterone is considered a male hormone because the amount of it in men is several times greater than in women, but the hormone is also present in the female body and is very important.


When testosterone is present in the ideal levels in the body of women, there is the maintenance of the disposition and the capacity of memory, besides guaranteeing a healthy increase in muscle mass. There is also regulation of sexual desire and cardiac protection.

What is it for: what is the function of testosterone in the body?

Testosterone is an androgen , a hormone that stimulates the development of male characteristics in vertebrate animals like us, humans.

Among androgens, testosterone is the most famous of them and its functions are diverse.

Protein synthesis

Testosterone promotes protein synthesis and is therefore an anabolic. These proteins are used, among other things, for building muscle mass. It is because of this property of testosterone that muscle growth is easier for men than for women, who have less of the hormone in their body.

This effect is particularly noticeable during puberty, when there are spikes in testosterone in the male body.

Growth of androgen receptors

Testosterone is one of the first androgen hormones to appear in the human body. It causes the growth of androgen receptors, which will be responsible for interacting with other androgens when necessary.

Development of male fetal characteristics

Still in the fetal phase, it is testosterone, along with other androgen hormones such as hydrotestosterone, that makes the genital transformation of the fetus, developing the penis, testicles, as well as the prostate and seminal vesicles.

Prepubescent changes

Near puberty, children of any gender begin to see hair growth on the body, growth spurts, the appearance of body odor and increased oiliness of the skin and hair. These changes are caused by testosterone, which increases between 10 and 13 years of age in both sexes, considerably more in boys.

Facial bones also begin to show changes due to the hormone at this stage, which brings about maturation.


In the case of boys, because of testosterone, the production of sperm begins, which makes the boy fertile.

Without the hormone, at any stage of life, this production is not viable and the person becomes infertile.

When the testosterone concentration in the man’s body is above average, there is a greater ejaculatory flow and a greater presence of sperm.

Testosterone also influences sperm quality (the viability of sperm and their ability to reach the egg).

In addition, the presence of testosterone affects the capacity and frequency of erections.

Deepening of the voice

Boys’ voices thicken during puberty because of the effects of testosterone. The hormone causes the larynx to increase in size. The female voice also changes thanks to this growth, but as it is considerably higher in boys, the change is clearer in them.

The larynx grows, on average, 4 mm in girls and 1 cm whole in boys, due to the greater amount of testosterone.

Appearance and physical performance

The presence of testosterone is responsible, among other things, for the growth and maintenance of muscles and the control of the proportion of muscles and fat. When the concentration of the hormone is higher, there is a reduction in fatty tissue and an increase in muscle.

Increased libido

Every day the hormone is produced, secreted and eliminated by the body through urine. During sexual arousal, production increases and so does testosterone concentration.

This happens at any point in life and in both sexes after puberty, when there is an increase in the amount of hormone produced in relation to childhood.

There is a connection between the concentration of testosterone in the body and libido (sexual desire). The greater the amount of the hormone, the greater the desire. However, the relationship is clearer in men, since testosterone does not always have an effect on female libido.

In men, the presence of testosterone also influences the frequency of erections. The higher the concentration of the hormone (within healthy standards) the more frequent the erections.

Bone changes

The bones of the whole body change during puberty thanks to hormones like testosterone. In the case of boys, the rib cage expands and the shoulders widen. The facial bones remodel and there are changes in the nose, jaw, forehead and chin, as well as in several other parts of the body.

In addition, the hormone is also used by the body to keep bones strong.

Cardiovascular function

The cardiac muscle is benefited by the presence of testosterone, reducing the risks related to cardiac functions. The cardiac ventricles are also stronger due to the action of the hormone.

Lack of testosterone hormone

The lack of testosterone can be caused by aging or hypogonadism, a disease that causes the testicles to produce little or no testosterone, and brings several problems to the male body.

Aging, on the other hand, usually causes a reduction in the amount of testosterone in the body, often without another associated cause. It is also estimated that the aging process facilitates the appearance of hypogonadism, reported in only 7% of men under 60 years old, but in 20% in those over 60 years old.

This is called andropause . Andropause is the reduction of testosterone production by the body and happens from the age of 35 or 40, but in most men, there are no noticeable symptoms.

Among the problems that can be caused by the reduction or lack of testosterone in the male body are:

Bone mass reduction

The hormone is not only used for bone growth in adolescence, but also to keep these bones strong. With a lack of testosterone, bones can become weaker and more porous over time, triggering osteoporosis due to a lack of the hormone.

Cognitive problems

There are studies that indicate that the reduction of the testosterone concentration in the blood affects the memory, the attention and the spatial capacity (the capacity to perceive the size and volume of an object, as well as the spatial perception), being a factor for the cognitive decline and dementia, although there are no conclusive results on that.

One study indicated that hormone therapy, adding extra testosterone to the blood, showed no improvement or worsening in memory or other cognitive functions, but found a reduction in the risk of cardiovascular disease.

Mood changes

Lack of testosterone can make a man more irritable or sad, as well as leading to depression .

Muscle volume reduction

The high presence of testosterone is what gives men bigger muscles than women. When this hormone is present in fewer numbers, muscle volume drops and building more muscle becomes difficult.

Reduced libido

Testosterone is partly responsible for sexual arousal, not just male. The hormone is found in greater quantities during sex in both sexes.

When the amount of testosterone is below normal in the male body, libido is reduced, affecting perception and sexual stimuli.


Andropause is the reduction of testosterone production in men over 35 years of age. Unlike menopause , the female counterpart to the reduction of the sex hormone, this reduction does not happen all at once, presenting a slow and progressive hormonal reduction, sometimes asymptomatic.

Just as in the case of reduced testosterone concentration by other causes, symptoms, when present, are more pronounced based on the size of the hormone reduction in the body. On average, andropause decreases the amount of testosterone by 12% per decade in the male body.

Increased body fat

The hormone impacts several characteristics of metabolism. It is one of the reasons why some men over the age of 35 or 40 find it more difficult to lose weight.

With less testosterone, maintaining muscle mass is difficult and it converts to fat, giving that pat.

Hair reduction

Testosterone is the hormone that causes men to have a beard and hair on the trunk and genital region. With less of the hormone, hair growth is reduced.


As in menopause, men in andropause may experience hot flashes (hot flushes) due to a lack of sex hormone.

They are similar to hot flushes that affect menopausal women and happen for the same reason, the drop in sex hormones, but they are extremely rare in men.

Excess testosterone

Like everything else in the world, excess can be just as damaging as lack.

Excess testosterone can be caused both by dysfunctions, such as hypergonadism (increased production of the hormone by the testicles), and by hormonal addition in patients who do not need this type of treatment, such as steroids.

Symptoms of excess testosterone include:

Mood changes

Like a lack of testosterone, too much of it can cause mood swings, making the affected man more aggressive. The ideal is to have the right amount of the hormone in your blood.

Hair growth

Excess testosterone can increase the growth of hair on the face, chest, back, armpits, genital and anal area. The hair on the arms and legs is not affected by the increase in the amount of testosterone.

A curiosity, androgen hormones can stimulate or inhibit hair growth, depending on the region of the body, since hair follicles react differently to the same hormones.

That is why as we age, it is possible that some regions lose hair while others maintain normal follicular growth.

Muscle growth

Excess testosterone, associated with strength training, can cause muscle growth. This is the effect that causes many people to use testosterone-based anabolics, disregarding the other side effects.

Testicular atrophy

If there is an external source of testosterone, the body may stop producing it naturally and the testicles may become stunted. When testosterone drops, there is a reduction in libido. The person is dependent on the anabolic used when the excess is caused by the use of these substances.

This atrophy can also lead to infertility and impotence, which is independent of the presence or absence of testosterone. That is, even replacing the hormone, sexual performance and health can be affected, differently from desire.

Increased cholesterol

Cholesterol is the body’s raw material for the production of testosterone. If the body receives the hormone externally, it stops using raw materials, which accumulate more easily.

High pressure

Excess testosterone can cause increased pressure. It has a vasoconstrictive action when in high doses and reduces the diameter of blood vessels.

In addition, the pressure can become high due to the increase in the amount of cholesterol in the body, which accumulates when there is an excess of the hormone.

Breast augmentation

To deal with the excessive amount of testosterone, the body can convert it to estrogen, which causes emotional changes and enlargement of the mammary glands. It is an especially common side effect in men who use anabolic steroids.

Effect of excess testosterone in women

Women may also have excess testosterone when they use anabolic steroids based on the hormone. The result is a masculinization of the female body, resulting in:

  • Thick voice;
  • Hair growth (facial and belly);
  • Jaw enlargement;
  • Clitoral enlargement;
  • Breast reduction;
  • Increased appetite;
  • Reduction of natural testosterone production;
  • Acne.

What is the right testosterone level?

The indicated amount of testosterone varies according to sex and age. In men, the hormone is more abundant than in women and it can be seen that between 15 and 18 years of age is when there is a greater quantity in both sexes, stabilizing at the end of puberty, from the age of 19.

Testosterone in the body is measured in nanograms (ng) per deciliter (dL). One gram is made up of a billion nanograms and one deciliter is equivalent to one tenth of a liter.

Men and women have differences in their hormone production, which also varies with age. The amounts of testosterone expected for each at specific ages are:


  • From 0 to 5 months: 75 to 400 ng/dL;
  • From 6 months to 9 years: 7 to 20 ng / dL;
  • From 10 to 11 years: 7 to 130 ng / dL;
  • From 12 to 13 years: 7 to 800 ng / dL;
  • 14 years: 7 to 1200 ng/dL;
  • From 15 to 16 years: 100 to 1200 ng / dL;
  • From 17 to 18 years: 300 to 1200 ng / dL;
  • From 19 years old: 240 to 950 ng / dL;


  • From 0 to 5 months: 20 to 80 ng/dL;
  • From 6 months to 9 years: 7 to 20 ng / dL;
  • From 10 to 11 years: 7 to 44 ng / dL;
  • From 12 to 13 years: 7 to 75 ng / dL;
  • 14 years: 7 to 75 ng/dL;
  • From 15 to 16 years: 7 to 100 ng / dL;
  • From 17 to 18 years: 20 to 75 ng / dL;
  • From 19 years old: 8 to 60 ng / dL;

What can reduce testosterone?

There are some factors that can cause a reduction in testosterone in the body. Among them are:

  • Stress;
  • Lack of sleep;
  • Obesity;
  • Use of anabolics;
  • Diet rich in sugar and fat;
  • Testicular lesions;
  • HIV;
  • Diabetes;
  • Andropausa;
  • Pressure control medications (statins);
  • Hypogonadism.

Bodybuilding and testosterone

Testosterone is the hormone that stimulates muscle building in the human body. An increase in its amount can be sought by those who would like an accelerated muscle growth.

Physical exercises also increase the production of the hormone in the body, which in turn helps to increase the muscles, facilitating exercises, forming a cycle.

The healthy ways to increase muscle are through exercise and a balanced diet with this focus, it is also possible to use a good sleep habit and food supplements.

But one of the ways that people looking to increase muscle mass are using anabolic steroids. These substances can increase the amount of the hormone in the body, but they can also bring about several health problems.

Hypogonadism is one of the problems that can arise due to the use of anabolic steroids, since when the body receives testosterone, it stops producing it and the testicles can become atrophied.

What to do to increase testosterone naturally?

Using anabolic steroids is harmful to health when testosterone levels are normal. However, there are ways to stimulate the body to produce more of the hormone in a natural way, maintaining healthy levels and ensuring the benefits of testosterone. Are they:


Some foods help the body to produce more testosterone by containing vitamins and minerals needed for this hormone production. Among them are:


Zinc-rich foods like oysters, liver, sunflower seeds and beans can help with testosterone production.

Vitamin D

Vitamin D can be acquired through food and especially by exposure to sunlight. Sunbathing for 15 to 20 minutes a day ensures adequate absorption of the vitamin.

Since the use of sunscreen inhibits the production of vitamin D through sunlight, it is important to be exposed only during this short period of time, during times of low sun exposure, and then use the sunscreen to prevent skin cancer and other injuries.

Vitamin A

Foods that contain vitamin A include mango , egg, cheese, milk, papaya and others. This vitamin is also used for the production of testosterone.

Physical exercises

Physical exercise, especially weight lifting, which forces muscles, can stimulate testosterone production to supply this muscle demand. Studies indicate that this effect may be more relevant in overweight or obese people.

Food suplements

Unlike anabolic steroids, which inject the hormone directly into the bloodstream, causing side effects such as reduced testicle production, dietary supplements give the body the material it needs to produce more testosterone naturally.

Among the supplements that can be used are:

  • D-Aspartic acid: amino acid that acts in the regulation of hormones;
  • ZMA : composed of zinc, magnesium and vitamin B6;
  • Gamma Oryzanol: active component extracted from grain oil.

In addition to these, there are some foods that, although not classified as supplements, can increase the production of testosterone in the body. Are they:

  • Tribulus terrestris (Androsten);
  • Maca peruana (Premium Unilife);

It is important to note that tribulus terrestris is only suggestive of testosterone. In other words, the studies that seek to find this information are not definitive, they just indicate this possibility.

Remember not to take supplements without consulting a doctor or nutritionist, as there may be side effects related to these substances.

Testosterone hormone treatment

Hormone replacement is the addition of synthetic hormones to the body. In the case of testosterone, steroids are used to replace what the body no longer produces.

This treatment is recommended in cases of hypogonadism, the condition that prevents the body from producing testosterone naturally, and other conditions, as long as recommended by the doctor.

US research has shown that less than 5% of men with hypogonadism or a lack of testosterone caused by aging undergo treatment, indicating that many people who could use hormone replacement do not.

In some cases, it can be used when there are symptoms during andropause, but the doctor will not always recommend therapy because of its possible side effects.

Medicines used for hormone replacement can be administered in three ways.

Testosterona gel

Testosterone gel is a method of hormonal treatment that consists of applying a gel with some percentage of testosterone to the skin. The hormone is then absorbed by the skin, increasing its concentrations in the body.

Injectable testosterone

Injectable testosterone is applied via a syringe with a needle. It is injected directly into the muscles and increases the concentration of the hormone in the body.

It is important to emphasize that the applications must be carried out by specialized professionals.

Testosterone tablet

Testosterone replacement can also be done through tablets taken orally, increasing the amount of the hormone in the body.

Among the drugs used for hormonal treatment are:

  • Durateston ;
  • Deposteron ;
  • Proviron;
  • Nebido;
  • Choriomon M.


NEVER  self-medicate or stop using a medication without first consulting a doctor. Only he will be able to tell which medication, dosage and duration of treatment is the most suitable for his specific case. The information contained in this website is only intended to inform, not in any way intended to replace the guidance of a specialist or serve as a recommendation for any type of treatment. Always follow the instructions on the package insert and, if symptoms persist, seek medical or pharmaceutical advice.

Common questions

Does testosterone replacement have benefits for body composition?

Only if you are lacking the hormone. If your body is not producing enough testosterone, it is possible that your bones will be weakened, your muscles will lose strength and there may even be risks to your heart.

However, if there is no condition caused by a lack of testosterone, adding more hormones will not simply improve the situation, it may even pose risks.

Which doctor takes care of testosterone?

The doctor who handles testosterone-related problems is the endocrinologist . He is responsible for the hormone-excreting glands and if there is a problem with testosterone, he is the doctor trained to treat it.

Can a woman use testosterone?

Avoidance is recommended. The woman has natural testosterone and if production is stopped, it is possible that she needs replacement. However, it is important to remember that the hormone concentrations in the female body are naturally much lower, so the amount of testosterone used in replacement should be lower.

When women have too much testosterone in their bodies, symptoms related to masculinization can arise.

The more testosterone I use, the more muscles will I gain?

No. Testosterone helps muscles to grow, but taking more testosterone than necessary will only lead to health problems over time, problems that can be extremely serious.

What causes a lack of testosterone in the female body?

Some very common factors can impact the production of testosterone in the woman’s body. Among them, the use of medications, such as contraceptives, stress and even an inadequate diet can result in changes in adequate hormone production.

Low testosterone fattening? Does it make hair fall out?

It is possible that low testosterone mainly causes men to gain weight or notice hair loss. The change in weight is not always so noticeable, but if bad or unhealthy habits are associated, the possibility of gaining weight is greater.

Testosterone is an essential sex hormone for both sexes, but present in greater quantities in men. It stimulates muscle growth, hair on the body and face, as well as playing an important role in sexual arousal. It can give you health problems both when in excess and when you are lacking.

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