Dr Jeff Foster, one of the UK's leading experts on the male sex hormone, has written a new book titled Optimal: Understanding Testosterone for Strength, Health, and Wellness. In it, he picks apart common myths and explains what men need to know to stay healthy.
What Testosterone Actually Does
Testosterone is both androgenic and anabolic. It promotes metabolism and protein synthesis, affecting muscles and bones, and drives masculine characteristics. Produced in the testicles, it is released into the bloodstream and influences brain function, kidneys, heart, bones, and fertility.
According to Dr Foster, testosterone contributes to drive, energy, metabolism, brain health, skeletal and heart health. Low testosterone can lead to fatigue, grumpiness, increased risk of heart attack, osteoporosis, and even death.
Testosterone Deficiency
Three main causes reduce testosterone levels: insufficient production from the testicles, the brain failing to signal the testicles to produce testosterone, or lifestyle and ageing decreasing system efficiency.
Dr Foster notes that low testosterone in men is associated with poorer health outcomes. He states, “You can choose to grow old, and become impotent and frail, or you can do something about it.”
Myths and Truths
Male Menopause
A drop in male sex hormone has similarities to menopause in women. Testosterone deficiency, also known as male hypogonadism or andropause, is a real medical condition.
Sexual Abstinence
There is no evidence that abstinence from sexual activity increases testosterone production. A 2001 study of 10 men showed a rise over three weeks, but the study quality was poor.
Vasectomies
Vasectomies do not affect testosterone because the blood supply to the testicle is not altered.
Libido and Testosterone
While testosterone is linked to sexual desire, libido is influenced by multiple factors including oestrogen, thyroid hormones, sleep, stress, weight, and experience.
Silent Low Testosterone
Many men in early stages of testosterone deficiency may not experience classic symptoms. This silent phase can affect metabolic health, mood, muscle mass, and cardiovascular risk.
TRT and Hair Loss
Testosterone replacement therapy does not itself cause baldness. Hair loss is linked to sensitivity to dihydrotestosterone (DHT), not total DHT levels.
Alcohol
Small amounts of alcohol act as a disinhibitor, increasing libido, but have little effect on testosterone.
Am I Too Old for TRT?
There is no age restriction for starting testosterone replacement therapy. However, in young men, caution is advised unless there is a clear reason.
Where to Seek Help
If feeling unwell, see a GP. Even if testosterone levels come back low, NHS treatment may not be available. “Normal” in the NHS may not reflect healthy levels, as factors like free testosterone may not be considered.
