Understanding Men’s Hormones
Answers to common questions about understanding men’s hormones.
Questions on this page
What is testosterone?
Testosterone is the major male sex hormone. It is important for sexual development, libido, muscle mass, bone health, red blood cell production, mood and sperm production.
Where is testosterone produced?
Most testosterone is produced by the testes. A small amount is produced by the adrenal glands.
What controls testosterone production?
The brain and testes work together through the hypothalamic-pituitary-gonadal axis.
The hypothalamus releases GnRH → the pituitary releases LH and FSH → the testes produce testosterone and sperm.
Does testosterone naturally decrease with age?
Testosterone production can gradually decline with ageing, but low testosterone should not automatically be attributed to age. Symptoms and appropriately performed blood tests are important.
What are the symptoms of low testosterone?
Possible symptoms include:
- Reduced sexual desire
- Erectile difficulties
- Reduced morning erections
- Fatigue or reduced energy
- Loss of muscle mass
- Increased body fat
- Reduced bone density
- Mood changes
- Reduced fertility
These symptoms can also occur because of obesity, diabetes, poor sleep, medications, depression and other medical conditions.