What is low testosterone?

Hormones are made by your glands and carried through the bloodstream, giving signals to other organs in the body about functions like growth, metabolism and reproduction.

Androgens are a group of hormones, and include testosterone (the male sex hormone). At puberty, your testicles start to produce testosterone, giving signs to your body that help it become sexually mature.

Low testosterone (or testosterone deficiency) is when the body isn’t able to make enough testosterone to work normally. Because testosterone is the major androgen, it’s key not just for the physical changes that happen during puberty (like the development of the penis and testicles, and the growth of body hair), but for your bone and muscles, sex drive, and your general mood.

Your testosterone levels are at their highest between the age of 20 and 30. As you age, you’ll experience a small, gradual drop in testosterone levels. You might have a greater drop in testosterone levels if you’re overweight or have other long-term medical problems.

Male hormones_Diagram

What are the symptoms of testosterone deficiency?

The symptoms of testosterone deficiency are different depending on your age.

Early childhood

  • Micropenis (penis does not grow to expected size)

  • Small testes







Early teenage years (puberty)

  • Late puberty or failure to go through full normal puberty

  • Small testes and penis

  • Poor development of facial, body or pubic hair

  • Poor muscle development

  • Voice does not deepen (larynx underdeveloped)

  • Gynecomastia (breast development)

  • Poor growth (height) surge


  • Mood changes (low mood and irritability)

  • Poor concentration

  • Low energy (lethargy, low stamina)

  • Reduced muscle strength

  • Increased body fat

  • Decreased libido (low interest in sex)

  • Difficulty getting and keeping erections (uncommon)

  • Low semen volume

  • Reduced beard or body hair growth

  • Gynecomastia (breast development)

  • Hot flushes, sweats

  • Osteoporosis (thinning of bones)

Later life (after 60 years)

  • Mood changes (low mood and irritability)

  • Poor concentration

  • Easily fatigued

  • Poor muscle strength

  • Increased body fat

  • Decreased libido (low interest in sex)

  • Difficulty getting and keeping erections

  • Gynecomastia (breast development)

  • Osteoporosis (thinning of bones)





What causes testosterone deficiency?

Testosterone deficiency may be due to problems within your testicles or with hormone production in the brain. This can be because of genetic disorders, medical problems, or damage to the testicles. Klinefelter syndrome is a genetic disorder that causes testosterone deficiency. Testosterone deficiency is also a common side-effect of anabolic steroid use.

What are the treatments for testosterone deficiency?

Medically-diagnosed testosterone deficiency is treated with testosterone therapy, which is  prescribed by a doctor. Once started, testosterone therapy is usually continued for life, and needs to be checked regularly.

If you have diabetes and testosterone deficiency, it’s best to get treatment for the diabetes and any other illnesses first, as this might return your testosterone levels to normal.

If you’re overweight, weight loss and a healthy lifestyle might help to improve your testosterone levels.

Your doctor’s appointment

Questions to ask your doctor

  • Will testosterone therapy improve or cure all of my symptoms?

  • What is the best type of testosterone therapy for me and why?

  • How long will it take to notice changes? Will I need lifelong testosterone therapy?

  • What are the side-effects of testosterone therapy? How will these be monitored?

Things to think about before your appointment

  • Have you experienced symptoms such as low mood and energy, low sex drive, or breast growth (man-boobs), and when did you first notice these symptoms?

  • Have you ever had any damage to your testicles such as childhood surgery, infection (such as mumps) or swelling of testis?

  • Have you ever had any kind of testosterone therapy?

Email these questions to yourself to take into your doctor's appointment.


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