Is it my testosterone?

What symptoms make low testosterone more likely?

Reduced sexual desire is generally a stronger clue than erection difficulty alone. Other possible features include reduced spontaneous erections, fatigue, loss of body hair, reduced muscle mass, infertility or small testes—although none is specific by itself.

Why does timing of the blood test matter?

Testosterone varies through the day and between days. Diagnosis should not rest on an isolated convenient sample. A low result normally needs confirmation with appropriately timed repeat testing and interpretation alongside symptoms and, where indicated, SHBG/free testosterone, LH, FSH and prolactin.

Will testosterone fix ED?

If a man has genuine hypogonadism, testosterone treatment may improve libido and can improve erectile response. A meta-analysis of eight studies involving 913 men with ED and hypogonadism found testosterone plus a PDE5 inhibitor improved erectile-function outcomes more than PDE5 inhibitor alone, although benefit depended on baseline testosterone and clinical context.¹

What if my testosterone is normal?

Giving testosterone to a eugonadal man is not an evidence-based general ED treatment and can create harms. In men who want fertility, exogenous testosterone can suppress LH/FSH and sperm production, sometimes profoundly.

What else commonly causes ED?

Vascular disease, diabetes, medications, pelvic surgery, neurological disease, psychological factors, sleep problems and relationship context are all common. A testosterone result should sit inside that assessment, not replace it.

How a testosterone test should actually be done

The British Society for Sexual Medicine is specific, and this is where most direct-to-consumer testing falls down. The sample must be taken fasting, between eight and eleven in the morning, and repeated before any diagnosis is made, because testosterone is pulsatile and varies substantially through the day.

A total testosterone consistently below 8 nmol/L usually warrants treatment; between 8 and 12 nmol/L a supervised trial may be justified alongside symptoms and further tests. A single afternoon finger-prick sample sold online cannot establish any of this — and NHS testosterone dispensing rose by more than half in four years while private clinics were being described in the pharmaceutical press as moving the goalposts.

Bottom line

Testosterone should be measured when the history makes deficiency plausible—not used as a default explanation for every erection problem. If deficiency is confirmed, treatment can be valuable; if it is not, the search for the real cause should continue.

Testosterone is pulsatile, so the sample has to be taken fasting, between eight and eleven in the morning, and repeated before anyone acts on it. If you are genuinely deficient, treatment can help a great deal. If you are not, testosterone will not fix your erections and may cost you your fertility — which is a conversation worth having before, not after.