According to an endocrinologist at Mediclinic Durbanville, Dr Chris Greyling, men generally start to experience a gradual decrease in testosterone levels at about the age of 40.
“This decline, averaging 1% to 2% per year, is a natural phenomenon. However, factors such as obesity and type 2 diabetes mellitus can accelerate this process. By age 70, almost one-third of men may experience significant hypogonadism, meaning their body doesn’t produce enough testosterone or sperm or both,” said Greyling.
Testosterone is a hormone produced in the testes and is crucial for male characteristics, sperm production, and sex drive. Levels peak in the teens and early 20s, supporting body hair growth, voice deepening and muscle strength, along with behavioural changes such as increased assertiveness.
While some men are born with low testosterone or develop it due to injury, autoimmune disease or cancer, most experience a gradual decline with age.
Greyling said testosterone deficiency typically arises from three main causes:
- primary hypogonadism — originating from testicular issues such as trauma or infections;
- secondary hypogonadism — resulting from pituitary gland dysfunction, often associated with obesity or chronic diseases; or
- tertiary hypogonadism — caused by hypothalamic abnormalities, including tumours or genetic conditions such as Kallmann syndrome, which can lead to diminished libido, erectile dysfunction and decreased muscle strength.
Associate director of Pharma Dynamics’ scientific division, Ingrid Singels, said many men dismiss early symptoms such as fatigue, low mood or a fading sex drive as stress or normal ageing.
“For some, these subtle changes may point to a deeper issue, and recognising it early and seeking medical advice can make a big difference to a man’s long-term health and quality of life,” she said.
Singels added that lifestyle factors play a key role.
“Secondary hypogonadism can occur when the hypothalamus or pituitary gland fails to send the proper signals to trigger testosterone production,” she said. This can put people at risk of chronic conditions such as obesity, type 2 diabetes, HIV and poor sleep, among other things.
She also highlighted late-onset or adult-onset hypogonadism, which develops gradually with age and is more common in men who are overweight or live with chronic conditions such as type 2 diabetes and cardiovascular disease.
Greyling said while low testosterone manifests in physical and mental ways, other common signs include: fatigue; mood disturbances such as depression and anxiety; diminished sexual desire and erectile dysfunction; infertility; weight gain and loss of muscle mass; reduced facial and body hair growth; and decreased bone density, increasing the risk of fractures.
Singels said lifestyle modifications can help reduce the risk or slow testosterone decline through:
- maintaining a healthy body weight, particularly by reducing abdominal fat;
- regular exercise, especially strength training;
- good sleep hygiene and treatment of sleep disorders such as sleep apnea;
- managing chronic conditions such as diabetes, hypertension and high cholesterol;
- limiting alcohol intake and reducing stress; and
- following a balanced diet.
Singels said Pharma Dynamics has digitised the ADAM Screening Questionnaire for Low Testosterone, which allows men to assess their risk online, download results and share them with their doctor.
Greyling said treatment options vary and should be tailored to individual needs. However, options may include AndroGel, which is a topical testosterone gel with unpredictable absorption and a risk of transfer to others.
Another option would be Depo-Testosterone, which is an intramuscular injection every three weeks, providing a stable hormone level. Nebido, which is a long-acting injection every three months, ensuring predictable absorption, can also be recommended by the doctor.
“Hormone therapy can rejuvenate libido, improve erectile function and restore sexual vitality. However, a holistic approach is essential, including lifestyle modifications and psychological support,” said Greyling.
Singels said for men with confirmed low testosterone, testosterone replacement therapy, which offers the most direct solution, could be another solution.
“Testosterone underpins much of what men take for granted: strength, drive, focus and mood. When it dips, the effects ripple across body and mind,” said Singels.
Greyling said early recognition and a diagnosis by an endocrinologist, as well as a personalised treatment plan, are key to managing symptoms and improving quality of life.
“Men shouldn’t ignore the subtle warning signs. Seeing an endocrinologist early can help prevent long-term complications and restore vitality, strength and confidence.”
This article was first published in TimesLive.
