In short
Overview
There is a defined threshold for starting testosterone, and it is higher than most clinics apply. Knowing where it sits tells you whether you are a candidate or a customer.
Direct Answer
Two things have to be true together: symptoms and signs consistent with androgen deficiency, and a distinctly subnormal morning testosterone on three separate occasions, taken between 8 and 10 am and ideally fasting.
Neither alone is enough. Symptoms with a normal level do not qualify, because raising a normal level does not relieve them. One low reading does not qualify either.
Where both are true, the benefits are described as clear, and treatment is appropriate.
Who This Applies To
- Men with a pituitary or hypothalamic cause, such as a tumour, previous radiation or a known deficiency
- Men with primary testicular failure, from injury, surgery, chemotherapy or a genetic cause
- Men with the specific symptoms and repeatedly subnormal morning levels
- Men with vague symptoms such as fatigue and a single, not repeated, subnormal level. This is a strong recommendation against, not a marginal call
- Men whose problem is fertility rather than testosterone. Treatment makes that worse, not better
- Men with a history of prostate or breast cancer
Option Comparison / Decision Criteria
Over 50, or over 40 if African American or with a first degree relative affected: examination and PSA. A nodule, or PSA over 4, or over 3 at high risk, means urology first
Above 50 per cent, the cause is found and treated first
Moderate or severe symptoms are treated before starting
Severe and untreated may be worsened. Well treated on CPAP is fine
Uncontrolled heart failure is treated first, since testosterone retains a little sodium
Personal and family, since in one study 39 of 40 clot cases on testosterone had an undiagnosed clotting tendency
Why an In-Person Physician Review Matters
Why three samples, not one Testosterone varies through the day and between days.
A glucose load suppresses it acutely, which is why the sample should be fasting and taken in the morning. Starting on a single reading means a meaningful number of men are treated for a laboratory fluctuation, and once started, stopping is difficult because of the prolonged low period while your own production recovers. Why LH and prolactin matter They tell you why testosterone is low, and the cause can change the treatment entirely. Low testosterone from a prolactinoma, from opioids, from obesity or from primary testicular failure looks identical on a single number. Where the cause is treatable in itself, treating it is usually the better answer. Why a trial is not the way to find out Treatment on a trial basis is specifically advised against, for two reasons. The result cannot be interpreted, since improvement may be placebo, coincidence or the correction of something else. And cessation is genuinely difficult once the axis is suppressed. The examination Testicular size, breast tissue, body hair pattern and visual fields. A pituitary tumour presenting as low testosterone is found by looking at the visual fields, not by reading a panel.
Frequently Asked Questions
There is no single number that decides it. What is required is a distinctly subnormal morning testosterone, on three separate occasions, together with symptoms and signs consistent with androgen deficiency. Neither alone qualifies.
Possibly, but not on age alone. The Testosterone Trials suggest benefit for sexual function, mood, bone and anaemia in older men. The FDA still does not approve treatment for a low level with no cause other than age, so it is an individual discussion.
Because a trial is specifically advised against. The result cannot be interpreted, and once your own production is suppressed, stopping means a prolonged period of low testosterone while it recovers.
A history of prostate or breast cancer, a haematocrit above 50 per cent until investigated, moderate or severe urinary symptoms until treated, severe untreated sleep apnoea, uncontrolled heart failure, or wanting children in the near future.
Evidence
Where this information comes from
Every figure on this page is taken from the sources below. All of them are free to read, so you can check them yourself.
This page is general medical information and does not replace a personal consultation. Trial results are averages across large groups, not a prediction for any one person.