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Low libido, fatigue, reduce facial hair growth and sleepiness during the day can all be symptoms of low testosterone.

Why do men* need testosterone?

Testosterone is important for growth of the prostate and testes –  sperm development and testicular growth – and plays a role in the development of male secondary sexual characteristics: facial hair, muscle, and increased bone mass. At puberty, there is a surge in testosterone that results in the characteristic pubertal changes seen in adolescent males*. Testosterone also contributes to the growth spurt seen in puberty, as it stimulates growth hormone production in the pituitary gland. Testosterone also plays a role in energy levels, libido and sexual function. In addition testosterone helps men build and maintain bone density. 

How does low testosterone in men* occur?

Normally, a signaling pathway from the hypothalamus and pituitary gland in the brain directs the function of the testes. The causes of low testosterone can be divided into primary (affecting the testes) and secondary (due to a problem in the pituitary or hypothalamus). If your testosterone level is low, pituitary blood hormones (LH and FSH) will help to determine whether the problem is primary or secondary. If the low testosterone primary (is due to a problem with the testes) then the LH and FSH will be high, as the brain will increase it’s signalling to try to get the testes to produce more testosterone. If the LH and FSH are normal or low despite a low blood testosterone, this suggests that the brain (either the hypothalamus and/or pituitary) is not able to sufficiently signal the testes in the usual way to increase the testosterone levels. Once your doctor has an idea of whether the cause for low testosterone is in the testes or the brain, scans and sometimes genetic tests may be used to help to determine the exact cause. Primary (testicular) causes may include damage to the testes such as through injury, mumps infection or cancer treatment or genetic causes such as Kleinfelters syndrome. Pituitary causes of low testosterone may include a pituitary lesion or a an inflammatory condition of the pituitary for example. Hypothalamic causes can also include inflammatory conditions or lesions. A more common (and reversible) cause may be suppression hypothalamic activity caused by stress on the body. This can happen for example in men* who are very active and are not eating enough calories to match their exercise requirements. Similar to how women’s* periods stop due to stress on the body), in men*, the calorie deficit can lead to suppression of the pathway via which the hypothalamus and pituitary glands signal the testes to produce testosterone. Reversing the calorie deficit should lead to recovery (read our article on testosterone and male athletes).

How do I know if I have low testosterone?

Testosterone levels fall gradually as men age, but do not drop as precipitously as for women when they reach menopause. The most specific symptoms of low testosterone include loss of morning erections,and reduced testicular size associated with low libido. Men may also notice reduced muscle mass, fatigue and mood changes, breast tenderness and reduced growth of facial hair.

What should I do if I think I have low testosterone?

See your GP who can do a blood test to measure your testosterone level. The test needs to be done in the morning, when levels are highest. The H and FSH pituitary blood tests may be done at the same time. If the testosterone is low, you may need to see an endocrinologist. 

What about using testosterone if my levels are within the normal range?

The use of “performance-enhancing drugs” (PEDs) and various other supplements for fitness and improved physique occurs worldwide. Uptake is generally in cis-men with normal testosterone levels   These products will suppress testicular function (including spermatogenesis) with subsequent infertility.  There are also other side effects on the liver and heart that are related to the type of androgen and dose. There is no quality control with these products, and they are particularly difficult to stop using once they are started. The suppression of the testes can take many months to resolve, and men can feel exhausted, and fertility is often slow to be restored after using these products.   

You can download our free infographic on of low testosterone from the erhassociates.co.nz home page.