Low testosterone and hypogonadism: symptoms, causes, and treatment

Low testosterone levels can cause health problems in men for a variety of reasons — but what are the signs your levels may be low?

From the age of 30, it is natural for testosterone levels to begin to steadily decline at a rate of less than 2% each year [1]. It’s sometimes unhelpfully termed male menopause, but unlike menopause, hormone levels drop only very gradually.

However, for some men, low levels of testosterone — due to ageing, an underlying medical issue, or even some medications — can cause symptoms. When this happens, it is broadly termed testosterone deficiency syndrome (TDS) or male hypogonadism. 

In this blog we discuss everything you need to know about low testosterone and hypogonadism:

How common is testosterone deficiency?

One study found that testosterone deficiency syndrome in men aged 40–70 affects about 6%, and this figure doubled to 12% over nearly nine years of follow up [2]. Low testosterone levels alone (regardless of symptoms) were found to affect nearly four in ten men over the age of 45 [3]. 

The prevailing finding is that testosterone deficiency becomes more common with increasing age, and it’s much more likely among people with diabetes or obesity [2]. 

What are the symptoms of low testosterone?

Testosterone has many important roles within the body. It helps to regulate many functions including [4]:

  • Mood
  • Memory
  • Concentration
  • Bone density
  • Building muscle
  • Metabolism
  • Libido
  • Fertility

It can also help protect against health conditions such as cardiovascular disease.

Symptoms of low testosterone can vary depending on the extent of the deficiency. The three most common symptoms are erectile dysfunction, loss of early morning erections, and reduced libido [5]. 

Some symptoms are typical of testosterone deficiency, while others are more generic and may be due to a combination of reasons.

Symptoms suggestive of testosterone deficiency include [6]:

  • Erectile dysfunction
  • Loss of early morning erections
  • Reduced sex drive (libido)
  • Enlarged breast tissue
  • Loss of body hair
  • Small or shrinking testes
  • Reduced sperm count
  • Reduced muscle bulk and strength
  • Hot flushes

Other non-specific symptoms that may be due to testosterone deficiency include [6]:

  • Decreased energy and motivation
  • Low mood
  • Poor concentration and memory
  • Sleep disturbance
  • Mild anaemia
  • Increased body fat

How can low testosterone affect your sex life?

Low testosterone can affect a man’s health and lifestyle, particularly in terms of sex life and relationships. 

Often, men with low testosterone have some degree of erectile dysfunction, including difficulty getting and keeping an erection, or erections occurring less often and not as strongly as before. Low testosterone levels can also reduce sexual desire (libido) [7].

Does low testosterone cause infertility?

Testosterone — and to a lesser extent, other hormones — play an essential role in sperm production. Therefore, testosterone deficiency can reduce the quantity of sperm, affecting fertility. Low testosterone is a relatively common cause of male infertility, representing about one in ten men with fertility problems [8]. 

Testosterone deficiency can also affect a man’s fertility indirectly by reducing the desire to have sex and causing erectile dysfunction. Having fewer erections or weaker erections can make it difficult to reach a climax or to have sex often enough to make a baby.

What causes testosterone deficiency syndrome/male hypogonadism?

Sometimes it’s possible to pinpoint the cause of low testosterone, but more often the cause is multifactorial and complex. Parts of the body that may be to blame are the testes, where testosterone is made, and the pituitary gland in the brain, where the production of testosterone is regulated. 

When not enough testosterone is produced and it causes symptoms, it’s termed hypogonadism, and there are two types. 

Hypogonadism is termed primary when the cause is related to the testicles (with raised LH/FSH levels), and secondary when related to the hypothalamus or pituitary gland (with lowered LH/FSH levels). In the ageing male population, it’s increasingly common to have a combination of both primary and secondary hypogonadism [9]. 

Primary causes of hypogonadism  [10]:

  • Mumps
  • Genetic and developmental conditions — Klinefelter syndrome
  • Chemo- or radiotherapy
  • Testicular trauma
  • Abnormal development of the testes — the absence of one or both testes or failure to descend

Secondary causes of hypogonadism [10]:

Mixed (primary and secondary) causes of hypogonadism [10]:

  • Ageing
  • Type 2 diabetes [11]
  • Alcohol abuse
  • Chronic infections, such as HIV
  • Corticosteroid treatment
  • Systemic diseases, such as liver failure or sickle cell disease

How do you test for hypogonadism?

When investigating hypogonadism, a blood test should be taken in the morning, before 10 am, to give the most accurate reading. This is because testosterone levels are naturally at their highest at this time.

Usually, in the first instance, if your doctor suspects hypogonadism, they’ll request a total testosterone level (Testosterone Blood Test). If this is low or borderline, they’ll then request a free testosterone test, usually with LH +/- FSH levels. Free testosterone is a measurement of the active form of testosterone. LH is useful to differentiate primary from secondary hypogonadism. And FH levels are useful if fertility is an issue. 

You can test your free testosterone levels, along with FSH and LH with our Male Hormone Blood Test.

Results should be interpreted by a doctor in context of your symptoms and medical history. 

Is low testosterone dangerous?

Studies have linked low testosterone in older men to a shorter life expectancy, due to the higher risk of death from heart disease and other causes [12]. However, it is not clear if this is just due to low testosterone or if there are other factors are involved. 

Men with low testosterone are also at increased risk for insulin resistance and type 2 diabetes [13].

If you have low testosterone, you can check your risk of diabetes with our Diabetes (HbA1c) Blood Test.

How do you fix low testosterone?

A low testosterone level alone doesn't necessarily need treatment, especially as borderline-low levels of testosterone can often be corrected by managing lifestyle factors.

Men with confirmed testosterone deficiency and accompanying symptoms may be considered for testosterone replacement therapy (TRT) by their doctor if it’s decided that the benefits would outweigh the risks and side effects in your situation. 

What happens if low testosterone goes untreated?

Even if your levels are low and you have symptoms, treatment with TRT is not always the safest or most effective option. Your doctor will try to identify the underlying cause and recommend appropriate lifestyle changes in the first instance — sometimes simple steps like losing weight or stopping a medication may help.

If your symptoms don’t improve or your deficiency is severe, your doctor will discuss other options with you, including the benefits and drawbacks of TRT


  1. NHS. 2019. The 'male menopause'. [online] Available at: <https://www.nhs.uk/conditions/male-menopause/> [Accessed 4 April 2022].
  2. Araujo AB et al. (2004) Prevalence and incidence of androgen deficiency in middle-aged and older men: estimates from the Massachusetts Male Aging Study. J Clin Endocrinol Metab 89: 5920–5926.
  3. Mulligan, T., Frick, M. F., Zuraw, Q. C., Stemhagen, A., & McWhirter, C. (2006). Prevalence of hypogonadism in males aged at least 45 years: the HIM study. International journal of clinical practice, 60(7), 762–769.
  4. Goodale, T., Sadhu, A., Petak, S., & Robbins, R. (2017). Testosterone and the Heart. Methodist DeBakey cardiovascular journal, 13(2), 68–72.
  5. Hackett G et al. 2017. The British Society for Sexual Medicine guidelines on adult testosterone deficiency with statements for UK practice. J Sex Med 14:1504-23.
  6. Tostain, J., Blanc, F. 2008. Testosterone deficiency: a common, unrecognized syndrome. Nat Rev Urol5, 388–396.
  7. Traish, A., 2018. Benefits and Health Implications of Testosterone Therapy in Men With Testosterone Deficiency. Sexual Medicine Reviews, 6(1), pp.86-105.
  8. Ohlander, S., Lindgren, M. and Lipshultz, L., 2016. Testosterone and Male Infertility. Urologic Clinics of North America, 43(2), pp.195-202.
  9. Carnegie C. (2004). Diagnosis of hypogonadism: clinical assessments and laboratory tests. Reviews in urology, 6 Suppl 6(Suppl 6), S3–S8.
  10. Dandona, P., & Rosenberg, M. T. 2010. A practical guide to male hypogonadism in the primary care setting. International journal of clinical practice, 64(6), 682–696.
  11. Dandona, P., & Dhindsa, S. 2011. Update: Hypogonadotropic hypogonadism in type 2 diabetes and obesity. The Journal of clinical endocrinology and metabolism, 96(9), 2643–2651.
  12. Muraleedharan, V., Marsh, H., Kapoor, D., Channer, K. S., & Jones, T. H. (2013). Testosterone deficiency is associated with increased risk of mortality and testosterone replacement improves survival in men with type 2 diabetes.
  13. Traish, A., Saad, F. and Guay, A., 2008. The Dark Side of Testosterone Deficiency: II. Type 2 Diabetes and Insulin Resistance. Journal of Andrology, 30(1), pp.23-32.

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