Testosterone, measured properly.

Testosterone is probably the most talked-about and worst-understood number in men's health. Levels decline slowly with age, but fatigue, low mood, poor sleep and a softer waistline are not automatically low testosterone, and a single reading taken at the wrong time of day can mislead in either direction. The guides below exist to replace forum folklore with what the evidence and UK clinical guidelines actually say.

A meaningful male hormone picture takes more than one marker. Total testosterone is the headline, but SHBG determines how much of it is actually available, which is why free testosterone and the free androgen index often explain symptoms a normal total cannot. LH and FSH show whether a low result originates in the testes or the pituitary, and prolactin can quietly suppress the whole axis. Read together, these markers turn a vague number into a pattern a clinician can act on.

Timing and repetition matter more than most men realise. Testosterone peaks in the morning, so guidelines recommend testing between roughly 7am and 11am, fasted, and never treating on the strength of one low reading. The British Society for Sexual Medicine's thresholds, the grey zone between clearly low and clearly normal, and the six common result patterns are all covered in the guides.

At-home testing works with a finger-prick kit posted to a UKAS-accredited UK laboratory, with results reviewed by a qualified clinician, usually within days. It suits a morning draw at home, a baseline before lifestyle changes, or tracking a borderline result over time. It is education rather than diagnosis: persistent symptoms or a clearly low result belong with your GP, and anyone considering TRT needs a proper clinical work-up first.