Testosterone is a steroid hormone that is produced in the testes in men, the ovaries in men and the adrenal cortex in both genders.

Testosterone is a vital hormone that affects the reproductive organs, brain, skin, muscles, heart and body weight.


What is testosterone?

Testosterone is a steroid hormone that is produced in the testes in men, the ovaries in women and the adrenal cortex in both genders.

Testosterone is a key male sex hormone that affects all aspect of male development and function.

Testosterone is a long established buzz word in the health and fitness arena, as it is known to improve endurance, increase muscle mass, promote fat loss, regulate sex drive and to promote better mood and memory.

Testosterone naturally declines as men age in a process called andropause which isn’t as well known as the menopause in women.

It can begin for men as young as 30 years of age. Andropause is marked by a decrease in the male hormone testosterone, also known as "Low T". Andropause differs to menopause as it is a more gradual process that involves testosterone declining over time.

Physically, testosterone affects the body by:

  • Stimulating the growth of male reproductive organs
  • Activating the enlargement of the Adam’s apple and deepening of the voice
  • Regulating the development of muscle mass and strength
  • Stimulating the growth of facial and bodily hair
  • Maintaining a healthy immune system
  • Producing red blood cells
  • Preventing osteoporosis and maintaining bone density
  • Maintaining a healthy heart
  • Stimulating erections
  • Regulating fertility and sperm quality

Emotionally, testosterone affects the mind by:

  • Improving short and long term memory
  • Balancing emotional responses and improving overall mood
  • Improving motivation and drive
  • Regulating sexual drive or libido
  • Maintaining energy levels


From the age of thirty years, testosterone levels begin to decline by 1% each year.

The rate of testosterone decline may be influenced by lifestyle factors such as being overweight, living a sedentary lifestyle, drinking, smoking, taking recreational drugs, significant stressors in your day to day life and emotional illness.

The Endocrine Society states that:

“There is a trend of declining testosterone in men and a rise in related health conditions, including reduced semen quality in men and genital malformations in newborn boys.”


What affects testosterone levels?

The pituitary gland, which is located at the bottom the brain, stimulates the production of testosterone by sending signals to the testes. When testosterone levels are too high, or too low in the blood, the brain sends signals to the pituitary gland to sends signals back to the testes. This signal will set off a chain of reactions which will either increase or reduce testosterone production, in a feedback loop.

Factors that may affect your testosterone levels include:

  • Diet
  • Exercise
  • Stress
  • Age
  • Family history
  • Certain health conditions

Health conditions including type 1 & 2 diabetes, Klinefelter syndrome, hemochromatosis, pituitary gland disorders, thyroid, kidney, liver issues, overtraining and eating disorders impact your testosterone levels.

Have you ever considered checking your testosterone levels? Now you can check your levels from the comfort of home with LetsGetChecked with online results available within one week.

Written by Hannah Kingston | Medically reviewed by Dr. Robert Mordkin