What is hypogonadism?

Male hypogonadism, also known as Testosterone Deficiency
Syndrome (TDS) or Androgen Deficiency Syndrome (ADS), occurs
when the body fails to produce enough of the hormone
testosterone.1,2 Although the condition can be present from birth,
it commonly develops in later life and affects men of advancing age.2

The exact definition of low testosterone level may vary, but it is generally accepted that
300ng/dL – 1000ng/dL is the normal range.2 [Figure 1]

Figure 1. The ranges of Testosterone level considered by a number of different sources to
be lower than normal. 1-3,6-11

Hypogonadism may be classified
as primary, secondary, late onset or
androgen insensitivity
(affecting target organs).

Primary hypogonadism (hypergonadotrophic hypogonadism) is the most common, and results from a testicular disorder. Sperm production is often impaired in patients with this type.

Physical damage to the testes, old age and exposure to radiation may increase the risk of developing primary hypogonadism.1,2,9,12,13

Secondary hypogonadism (hypergonadotrophic hypogonadism) is less common, and is associated with hypothalmic pituitary dysfunction. Whereas primary type is characterised by increased follicle stimulating hormone (FSH) and luteinizing hormone (LH), levels are low to normal in patients with secondary hypogonadism.

Clinical signs and symptoms of hypogonadism 1,6,14,15

Hypogonadism can have a huge impact on quality of life and vitality. A variety of different symptoms may be experienced by those with hypogonadism, depending on the age of onset, and the duration and severity of the condition:2

Delayed puberty

Small testes

Male-factor infertility

Decreased body hair

Gynaecomastia

Decrease in lean body mass
and muscle strength

Visceral obesity

Decrease in bone mineral density (osteoporosis) with low trauma fractures

Erectile dysfunction

Reduced sexual desire and sexual activity

Erectile dysfunction

Hot flushes

Changes in mood, fatigue and anger

Sleep disturbances

Metabolic syndrome

Insulin resistance and type 2 diabetes mellitus

Diminished cognitive function

The most prevalent symptoms of male hypogonadism in men aged 40-79 year, are reduced sexual desire and sexual activity, erectile dysfunction, and hot flushes.2

It should be noted that these symptoms are also found in men with normal testosterone levels and may have other causes than androgen deficiency.