Written by: Professor Malcolm Carruthers
Testosterone deficiency results from failure or disruption of the body’s normal process of production or uptake of the hormone. This can be due to any or a combination of:
- Problems with the testicles: 95% of male testosterone is made in the testicles. If testosterone production is insufficient, testosterone deficiency will result.
- Problems with the hypothalamus or pituitary gland in the brain: the testicles depend on hormonal signals from these areas of the brain to maintain adequate testosterone production. Testosterone in the blood itself then exerts negative feedback on the brain to ensure that levels remain adequate and balanced. Where this delicate balance is disrupted, testosterone deficiency can result.
- Poor body tissue response to testosterone or its metabolites (testosterone resistance)
These failures or disruptions can in turn be due to a variety of causes, including:
- Congenital defects, such as Kallmann’s Syndrome
- Disease (specific – pituitary adenoma, mumps or e.g. diabetes)
- Testicular injury
- Medication reactions
- Poor lifestyle
How common is testosterone deficiency syndrome?
Estimates vary widely but our research at the Centre indicates that 20% of men (2 million) across the UK over the age of 50 suffer from testosterone deficiency syndrome. However, only 1% have been diagnosed and are being treated. It is natural for testosterone levels to fall gradually with age.