Information for healthcare professionals

Symptoms, physical examination, and blood tests

The symptom most associated with hypogonadism is reduced libido, however other manifestations can also be associated with low testosterone, and a diagnosis of hypogonadism is made on the basis of low serum testosterone levels occurring in association with one or more of the symptoms and signs listed in the Table.1,2 However, please consult guidelines relevant to your country of practice as country-specific differences in the diagnosis and treatment of hypogonadism exist.
Table 1: Signs and Symptoms of Hypogonadism
A. Signs and symptoms suggestive of hypogonadism in men B. Other, less specific symptoms and signs associated with hypogonadism
Incomplete sexual development, eunuchoidism, aspermia Decreased energy, motivation, initiative, aggressiveness, self-confidence
Reduced sexual desire (libido) and activity Feeling sad or blue, depressed mood, dysthymia
Decreased spontaneous erections Diminished physical or work performance
Reduced muscle bulk and strength Poor concentration and memory
Hot flushes, night sweats Increased body fat, body mass index
Loss of body (axillary and pubic) hair, reduced shaving Insulin resistance
Breast discomfort, gynecomastia Sleep disturbance, increased sleepiness
Very small or shrinking testes Mild anemia
Inability to father children, low or zero sperm counts  
Height loss, low trauma fracture, low bone mineral density (osteoporosis)  

The symptoms of hypogonadism may vary from individual to individual. In late-onset hypogonadism many symptoms resemble those of aging and as a consequence this condition is often undiagnosed. Various diagnostic procedures are available to confirm hypogonadism in a patient who presents with symptoms or signs of testosterone deficiency. These include:

  • Medical history (personal and familial)
  • A general physical examination including blood pressure, evaluation of secondary sexual characteristics, testicle examination, waist circumference measurement and distribution of fat
  • Examination of the prostate, as it is important to eliminate prostate cancer should testosterone therapy be indicated.
  • Laboratory tests including determination of testosterone values

Repeat measurement of morning total testosterone (when levels of serum testosterone can be expected to be higher because of the diurnal rhythm of testosterone) using a reliable assay is recommended by international professional societies in the field as the most widely accepted parameter to establish the presence of hypogonadism in combination with consistent symptoms and signs. In some men, determination of free or bioavailable testosterone may be appropriate.1,2

Supplementary tests, for example a bone density test for suspected osteoporosis or tests to exclude other diseases that may explain the symptomatology, may be necessary. The physician’s experience and, in some cases, the observation of clear clinical benefits after the initiation of testosterone therapy may provide confirmation of a diagnosis of hypogonadism.

The measurement of testosterone levels in the diagnosis of hypogonadism is summarized in the text box below

Measurement of testosterone levels in the diagnosis of hypogonadism

Values for normal testosterone ranges vary among laboratories depending on the commercial assay employed, and local values should be consulted when a diagnosis of hypogonadism is considered. There is no generally accepted lower limit of normal. However, a morning testosterone concentration in the blood of 12-35 nmol/L can be considered normal. Testosterone treatment might be recommended if this value is found to be below 12 nmol/L. There is general agreement that total testosterone levels above 12 nmol/L (346 ng/dL) or free testosterone levels above 250 pmol/L (72 pg/mL) do not require testosterone treatment. The European Association of Urology (EAU), International Society for the Study of the Aging Male (ISSAM), International Society of Andrology (ISA), European Academy of Andrology (EAA) and American Society of Andrology (ASA) suggest that serum total testosterone levels below 8 nmol/L (231 ng/dL) or free testosterone below 180 pmol/L (52 pg/mL) require testosterone replacement therapy. In addition, concentrations of the pituitary hormones can be measured. They provide information as to whether the testosterone deficiency is due to disorders of testicular function or of the hypothalamic-pituitary system.

Since symptoms of testosterone deficiency become manifest between 8 and 12 nmol/L (231–346 ng/dL), trials (3– >6 months) of treatment can be considered in men with a clinical picture of testosterone deficiency and borderline testosterone levels when alternative causes of these symptoms have been excluded.1,2

Please consult guidelines relevant to your country of practice as country-specific differences in the diagnosis and treatment of hypogonadism exist.


1 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.

2 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.
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Last updated: 2016