In short
Overview
Testosterone therapy has two large trials behind it now, and they say different things about different outcomes. This is what they actually found.
Direct Answer
In men with confirmed deficiency, testosterone improves sexual function, mood, bone density and anaemia, and possibly walking distance.
The TRAVERSE trial of 5204 men over about three years found it did not increase major cardiovascular events. It did increase atrial fibrillation, pulmonary emboli and fractures.
Fractures rose from 2.46 to 3.50 per cent of participants, mostly ankles, wrists and ribs, which surprised everyone because testosterone improves bone quality.
Who This Applies To
- Men with a confirmed subnormal morning testosterone, measured on separate occasions
- Men already on treatment who want to know what they are actually carrying
- Men weighing up whether to start
- Men with normal testosterone. Raising a normal level will not relieve symptoms, and the risk column still applies
- Men at high risk of prostate cancer, who were excluded from TRAVERSE, so its reassuring prostate result may not extend to them
- Men with a history of prostate or breast cancer, for whom treatment is generally not given at all
Option Comparison / Decision Criteria
The benefits, as measured
| Sexual function | Improved. The most consistent finding across trials |
| Mood | Improved |
| Bone density | Improved |
| Anaemia | Improved |
| Walking | Possibly improved |
| Erectile function specifically | In TRAVERSE, sexual activity and desire improved but erectile function did not |
The risks, as measured
| Major cardiac events | Not increased in TRAVERSE, which is the best evidence available and contradicts earlier smaller studies |
| Atrial fibrillation | Increased |
| Clots | 46 per cent higher rate, not quite statistically significant. Pulmonary emboli 24 against 12 |
| Fractures | 3.50 against 2.46 per cent. Ankles, wrists and ribs. Hip and spine fractures were not increased |
| Thick blood | 2.0 against 0.1 per cent across three trials. Very low where doses are kept in the normal range |
| Prostate cancer | Low and similar in both groups in TRAVERSE |
| Urinary symptoms | Not worsened across three separate analyses |
The one that is not a risk but a certainty
Testosterone suppresses sperm production and reduces testicular size. That is not a side effect to weigh, it is how the drug works, and it needs deciding on before you start.
Why an In-Person Physician Review Matters
Why the route of delivery changes the risk In both the Testosterone Trials and TRAVERSE, testosterone was given through the skin and doses were adjusted to keep the level within the normal range.
In both, the risk of thickened blood was very low. Thickened blood is mainly a problem of supraphysiological dosing with injectable esters. So the risk profile depends heavily on how it is prescribed, not just on whether it is prescribed. What has to be checked before starting Haematocrit. Above 50 per cent, the cause is investigated and treated first Prostate. Over 50, or over 40 at higher risk, a rectal examination and PSA. A nodule or PSA over 4, or over 3 at high risk, means urology first Urinary symptoms. Moderate to severe symptoms are treated before starting Sleep apnoea. Severe untreated apnoea may be worsened. Well treated apnoea on CPAP is fine Heart failure, which should be controlled first because testosterone retains a little sodium Personal and family clotting history. In one study, 39 of 40 clot cases on testosterone had a previously undiagnosed clotting tendency What has to be monitored afterwards Testosterone at two to three months, then every 6 to 12 months once stable. On a gel, two samples are taken before adjusting a dose, because levels vary unpredictably Haematocrit at three to six months, then yearly. Treatment is stopped if it reaches 54 per cent Prostate at three months and one year in men over 50, or over 40 at higher risk Half of men prescribed testosterone have no biochemical monitoring at all in the first six months. That is the gap that turns a manageable treatment into an unmanaged one.
Frequently Asked Questions
The best evidence says no. TRAVERSE, with 5204 men followed for about 33 months, found no increase in major adverse cardiovascular events. It did find more atrial fibrillation and more pulmonary emboli.
Nobody is sure, and it was unexpected because testosterone improves bone quality. Fractures rose from 2.46 to 3.50 per cent, mostly ankles, wrists and ribs. Hip and spine fractures were not increased.
Less reliably than it helps desire. In TRAVERSE, sexual activity and desire improved but erectile function did not. Where erections are the problem, it is usually combined with a PDE5 inhibitor rather than used alone.
Rates were low and similar between groups in TRAVERSE. But men at high risk of prostate cancer were excluded from the trial, so the result does not necessarily extend to them, and monitoring is still done at three months and one year.
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.