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Myth check

Tired all the time: is it low testosterone?

The evidence doesn't point there. Tiredness and low mood did not group with a falling level, and a year of treatment in men over 65 improved sexual function but not fatigue.

Testosterone

Tiredness, low mood and a fading drive are sold together as the signs of low testosterone. In 3,369 men, only the sexual symptoms held together as the level fell; tiredness and low mood did not, which shows how symptoms group rather than ruling them out. In a year-long treatment trial in men over 65, sexual function improved, desire only narrowly, and fatigue did not. A low level can sit behind a fading sex life; as the reason someone is worn out, the evidence has not found it.

The findings behind this

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Sexual & reproductiveTiredness and low mood did not group with a falling level

Nine symptoms popularly pinned on low testosterone were tested in 3369 men. Only three held together as testosterone fell: poor morning erections, low desire, erectile difficulty.

★★★Well replicated — this finding’s sources average out to meta-analyses, systematic reviews or high-powered trials.This is a snapshot, so it can say which symptoms travel with low testosterone and not whether raising it would relieve them. That fatigue and low mood failed to cluster is a statement about how symptoms group, not proof they have nothing to do with testosterone. Testosterone here was measured by mass spectrometry on morning samples, a stricter standard than much routine clinical testing, so the thresholds may not transfer to an ordinary lab result.Click to keep this openSupport sexual healthTestosterone
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Sexual & reproductiveSex drive improved and the tiredness stayed exactly where it was

In men over 65 treated for a year, sexual activity, desire and erectile function all improved. Fatigue and walking distance did not, and pooled trials found nothing on energy.

★★★Well replicated — this finding’s sources average out to meta-analyses, systematic reviews or high-powered trials.About 65 men were screened for every one enrolled, so these are not the men who walk into a clinic. One year of treatment is short against how long testosterone is actually taken. In the pooled analysis the sexual-desire interval ran from 0.01 to 0.34, close enough to zero to be worth naming.Click to keep this openSupport sexual healthTestosterone

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