Men's Health

The four systems behind male vitality

Hormonal. Testosterone is produced in the Leydig cells of the testes under pituitary LH signalling. Most circulating testosterone is bound to SHBG and albumin; only 1–2% is free and biologically active. Age raises SHBG, so free testosterone can fall meaningfully while total testosterone still reads as normal on a lab panel. This is why symptoms and blood results sometimes disagree.

Vascular. Erectile function, exercise capacity and even cognitive stamina depend on endothelial nitric oxide (NO) — a signalling molecule that relaxes smooth muscle and widens blood vessels. NO output declines with age, smoking, high blood pressure and poor glycaemic control. The penile arteries are among the narrowest in the body, which is why vascular decline often shows up there first, years before a cardiac event.

Metabolic. Visceral fat is hormonally active tissue: it expresses aromatase, which converts testosterone into oestradiol. Excess abdominal fat therefore lowers testosterone, and low testosterone promotes further fat gain — a self-reinforcing loop that is broken far more effectively by training and calorie control than by any capsule.

Psychological. Chronic stress raises cortisol, which suppresses gonadotropin-releasing hormone at the hypothalamus and depresses libido independently of testosterone. Sleep deprivation does the same: one week of five-hour nights measurably lowers daytime testosterone in healthy young men.

What supplements can and cannot do

A dietary supplement is not a medicine, and in the EU it may not legally claim to treat, cure or prevent disease. What well-formulated products can do is correct deficiencies (zinc, magnesium, vitamin D), supply substrate for pathways that are working but under-supplied (L-arginine, L-citrulline for NO), or provide adaptogenic plant compounds with a documented effect on stress response and subjective wellbeing (ginseng, ashwagandha, maca).

What they cannot do is replace testosterone in a man with clinical hypogonadism, resolve an arterial blockage, or substitute for the effect of losing 10 kg of visceral fat. Any product marketed as doing so is overreaching, and the sensible response is scepticism.

When to see a doctor rather than buy a supplement

Certain symptoms are signals to seek medical assessment first, not to self-treat: erectile difficulty that appears suddenly, blood in the urine or semen, unexplained weight loss, breast tissue development, testicular pain or a palpable lump, or a persistently weak urinary stream with incomplete emptying. Sudden-onset erectile dysfunction in particular is an established early marker of cardiovascular disease and warrants a blood pressure, lipid and glucose check.