Written by Pliro
Jun 10, 2019 Last updated: Jun 10, 2019

What is Testosterone?

Testosterone is a male sex hormone or androgen. Hormones in general are important for the normal function of the human body. They are produced in particular areas by living cells and then travel through fluids like blood to distant tissues or organs where they cause particular effects.

The gonads (testes and ovaries) are the main places where testosterone is produced. Males produce the highest amounts of this hormone but females do it too. Testosterone regulates a number of processes related to the development of sexual organs and secondary sexual characteristics (which appear during puberty).

Main functions

Scientist find more effects of testosterone over the male body every day, however, the most well-known include:

  • Regulation of sexual desire or libido
  • Increase of bone mass
  • Control of fat distribution
  • Increase of muscle mass
  • Regulation of red blood cell production
  • Promotion of sperm production

Normal Testosterone Levels for Men

Please keep in mind that normal levels can vary a lot between individuals.


  • Up to 5 months: 45 to 400 ng/dl
  • From 6 months to 9 years: < (7-20) ng/dl
  • 10 to 11 years:  < (7-130) ng/dl


  • 12 to 13 years: < 800 ng/dl
  • 14 years: < 1200 ng/dl
  • 15 and 16: < 1200 ng/dl


  • 17 to 18 years: < 1200 ng/dl
  • 19 years and up: <950 ng/dl

What if you have High Levels of Testosterone?

Testosterone levels usually drop with age, however, some men have excessively high levels, which can cause problems.

When total testosterone levels of an individual over 19 years old are above 950 ng/dL, he can be diagnosed as having to much of this hormone. Such a condition can actually lead to a lot of bad consequences like: Early puberty (in children), infertility (low sperm count), overactive sexual desire, excessive body hair, a lower voice pitch, high blood pressure, high red cell count and increased aggression.

Interestingly, having a lot of testosterone is not necessarily bad for the elderly, some authors suggest this state actually leads to a reduced risk for cardiovascular disease in this particular subpopulation.  

Abnormally high testosterone can be caused by: Adrenal tumors, hyperthyroidism, anabolic steroids, testosterone supplementation or coming into contact with testosterone gels.

Although this is not a very common condition its treatment can be very simple, Many recommend eating foods known for their effect over testosterone levels like: Soy, nuts, licorice and mint.

What if you have Low Levels of Testosterone?

Hypogonadism has received a lot more attention than its counterpart. This condition is much more common because it follows the normal development of men as they age. After 30 years old, men lose around 1% of their total testosterone each year, which can lead to a number of consequences frequently associated with old age. According to recent studies, over 40% of all 45 years old men have low testosterone levels.

Among the most common symptoms of low testosterone levels, we found: Low sexual desire, erectile dysfunction, depression, concentration and memory problems, fatigue, irritability, loss of strength, low haemoglobin, reduced body hair, osteoporosis, infertility and gynecomastia.

This condition has also been associated with an increased mortality risk among the elderly and diabetes (1 and 2).

Over the years, authors have found a great number of potential causes for hypogonadism, including but not limited to: Physical damage to the testes, chemotherapy, high levels of iron in blood, tumors in the pituitary gland, opioids abuse, hormone therapy for cancer treatment, steroids, alcohol abuse, liver cirrhosis, kidney failure, HIV infection, several inflammatory conditions, radiotherapy, head injury, etc.

Men who have low testosterone level but do not exhibit any symptoms do not require any treatment. For those who do, there is testosterone therapy which focuses on raising the amount of serum testosterone as a way to treat the symptoms.

Skin patches, topic gels, pellets and injections are few methods through which one can administer testosterone on regular basis.

Testosterone levels are required to be kept in control as the age increases. If you are over 40, please try to check yours at least 1 every few years to avoid any future complication. You may visit a sexologist for this purpose and book an appointment.