How to diagnose hypogonadism in men?

Doctors base a diagnosis of low testosterone on the presence of symptoms and the results of blood tests that measure testosterone levels.

Your doctor will ask you some questions to help understand what signs or symptoms you may be experiencing that suggest you have low testosterone. The symptom most associated with low testosterone is reduced sex drive (low libido), however your doctor will ask about a range of symptoms.

Because many of these symptoms are not necessarily only due to low testosterone, your doctor will perform a physical exam and may take a blood sample to measure testosterone levels.

Blood tests

Determination of testosterone values

Blood tests

Blood will usually be taken in the morning (between 7.00am and 11.00am) when testosterone in your blood is naturally at its highest level

Most of the testosterone in your blood is bound tightly by a protein called sex hormone-binding globulin (SHBG) and so it is not free to do its job. Because of this your blood may also be tested for levels of SHBG in order to work out how much of the total testosterone is free testosterone (also known as bioavailable or bioactive testosterone)

The results of these tests may need to be confirmed by taking a second sample

If tests confirm that you have low testosterone, additional tests may be required and you may be referred to a specialist. Your doctor will advise you of what additional tests are needed

Measurement of testosterone levels in the diagnosis of hypogonadism

Calculate the bioactive
testosterone circulating in plasma

Treatment options

Treatment of low testosterone is quite straightforward. Once the decision has been made to increase testosterone levels, low testosterone can be replaced by using one of a number of treatment options. All of these treatment options require a doctor’s prescription. An ideal preparation of testosterone will bring testosterone levels back into the normal range to reverse the symptoms of low testosterone. It will also be safe and offer a convenient dosing schedule and means of administration.

Several months of treatment may be required before changes are apparent. The general recommendations are to raise the blood testosterone level only into the middle of the normal physiological range. As testosterone therapy is long term, it is important that it is convenient, safe and effective.

Testosterone effects tool

Visualisation of the time course for onset of the many beneficial testosterone effects.


The benefits of testosterone replacement

The benefits of testosterone replacement on sexual function, fat and lean body mass and bone density in men with low testosterone are clear. The potential benefits of testosterone replacement in reducing the risk of cardiovascular disease, metabolic syndrome and diabetes are still being investigated.


  • Prevents anaemia


  • Controls sexual function (sex drive, erectile function, orgasm)
  • Reduces lower urinary tract symptoms (LUTS)
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  • Improves mood, energy, wellbeing and quality of life
  • Prevents depression

Physical symptoms

  • Increases muscle mass
  • Increases strength
  • Decreases overall body fat mass
  • Decreases belly (visceral) fat mass
  • Increases bone mineral density

Health and well-being – quality of life

Improvements in signs and symptoms of low testosterone, such as libido, sexual, physical and mental functioning and mood, can be expected over time and will show you that the treatment is working.

Body composition

Testosterone replacement in men with low testosterone increases lean body mass and strength and decreases fat mass.


Testosterone therapy may also have metabolic benefits in men with diabetes and/or metabolic syndrome. Men with diabetes have been shown to have substantially lower testosterone levels than men in the general population, yet low testosterone in many remains undiagnosed and untreated. It is not yet fully known whether diabetes is a cause or a consequence of low testosterone.


Low testosterone can lead to thinning of the bones (osteoporosis) and men with hip fractures tend to have low testosterone. Testosterone replacement increases bone density.

If low testosterone occurs during adulthood, you can make some lifestyle and dietary changes to help prevent osteoporosis. Regular exercise and adequate amounts of calcium and vitamin D help to maintain bone strength and are important to reduce the risk of osteoporosis.

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  • Bhasin S, Cunningham GR, Hayes FJ, et al. Testosterone therapy in adult men with androgen deficiency syndromes: an endocrine society clinical practice guideline. J Clin Endocrinol Metab 2006; 91(6): 1995-2010. Return to content
  • Wang, C., E. Nieschlag, R. Swerdloff, et al. Investigation, treatment and monitoring of late-onset hypogonadism in males: ISA, ISSAM, EAU, EAA and ASA recommendations. Eur J Endocrinol 2008, 159(5): 507-514. Return to content