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By Mike Kocsis | 3 minutes read |
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    Testosterone is an important hormone. As an androgen, it plays a vital role in the development of male physical characteristics , although it can also be found in lower levels in women. It is involved in a wide range of bodily processes without which the human body would not function properly. Here is a guide to how some of these processes work.

    Male sex organs

    Development of the male sex organs, including the growth of the penis and testes, begins in the womb and is primarily driven by testosterone levels. Testosterone also causes growth of the prostate gland. The development of male sex characteristics becomes more prominent during puberty. Testosterone is also responsible for continuously producing sperm and controlling sperm levels throughout adult life. As such, a lack of testosterone can cause reduced libido, impotence and even infertility.

    Secondary sexual characteristics

    In addition to male reproductive organs, testosterone is a key factor in the development of secondary sexual characteristics during puberty. Indeed, too much testosterone can cause puberty to begin early . Secondary sexual characteristics include the growth of the Adam’s Apple and the voice breaking and becoming deeper, as well as increased height and muscle mass (in turn leading to greater physical strength). In contrast, lower testosterone can lead to increased body fat.


    Testosterone also has an effect on the sex drive, starting during puberty and continuing throughout adulthood. It increases sexual arousal, with higher levels of testosterone in men being associated with higher levels of sexual activity and more frequent erections. Testosterone can impact the female libido as well.

    Facial and body hair

    Higher levels of testosterone are associated with more and thicker hair, including facial hair such as beards and moustaches. Hair may also grow in other parts of the body, such as in the armpits and on the chest. Women with higher levels of testosterone may also see increased facial hair growth. Conversely, testosterone can also contribute to baldness and the loss of hair on the scalp in women.


    Changing testosterone levels can cause skin issues. This is particularly prominent during puberty, when it can contribute to oily skin and acne.


    Increased competitiveness, aggression and confidence are associated with higher levels of testosterone. Testosterone levels can also have an impact on memory, mood and attention span. These changes can become apparent with puberty and continue into adult life. Lack of testosterone can lead to depression and fatigue.

    Bone density

    Testosterone can help maintain higher bone density throughout life, which in turn lowers the possibility of developing osteoporosis or fracturing a bone. As testosterone often lowers with age, this is one reason why older people may have lower bone density.

    Red blood cell production

    Another effect of testosterone is that it indicates to the rest of the body (particularly the bone marrow) when new red blood cells need to be produced. Red blood cells are vital to transport oxygen around the body. They are the most common type of blood cell in humans.

    Disease protection

    Some medical conditions, including cardiovascular disease and metabolic disease, are associated with lower levels of testosterone. As testosterone levels fall naturally with ageing, these conditions become more common. Research into the relationship between testosterone and heart health is ongoing.

    Other hormones

    Testosterone works with several other hormones and can, therefore, help control their levels just as they regulate testosterone levels. This includes gonadotropin-releasing hormone, luteinising hormone (LH) and follicle-stimulating hormone (FSH).

    About the Author: Mike Kocsis

    Mike Kocsis has an MBA with a focus on healthcare administration and is an entrepreneur and medical case manager for Balance My Hormones Ltd which offers medical services in the UK and Europe. Mike has over 20 years of experience in the healthcare sector, much of that working with people who have hormone imbalances. Mike has appeared on podcasts and radio and is an expert speaker on the subject of hormone imbalance. He specialises in Testosterone Replacement Therapy (TRT) and Hormone Replacement Therapy (HRT) and has helped thousands of people suffering from hormone imbalances recover and regain control of their lives. You can follow him on LinkedIn and on the Balance My Hormones YouTube Channel.

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    Last update: February 24th, 2021

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