Human
Do libido, mood and energy improve together?
Testosterone gel versus placebo for 1 year, titrated toward young-adult normal levels.
Demonstrated findings
Sexual activity, desire and erectile function improved. Mood improved slightly, but the primary fatigue measure showed no significant benefit.
Limitations & adverse findings
The study was too small to settle uncommon safety outcomes.
What might this mean? · interpretation
An effect on sexual function does not establish an equivalent effect on energy or motivation.
What might this mean, and what would change the interpretation?
790 symptomatic men aged 65 or older with low testosterone. Results do not predict responses in younger men or at higher exposures.
What would clarify this: Trials in younger symptomatic populations with prespecified energy and motivation measures.
Findings reviewed · abstract
Checked Sep 15, 2026 against the linked abstract. This reading note is not a formal risk-of-bias appraisal.