Testosterone
The main male sex hormone, and what genuinely raises or lowers it.
Last revised
Key takeaways
- Testing: a morning blood sample, repeated to confirm
- Common alternative explanations: sleep apnoea, depression, thyroid disease, anaemia
- Most useful single change: Ask for the other causes to be excluded before attributing symptoms to testosterone.
- Commonest mistake: Buying testosterone or anabolic steroids online.
- See a doctor if any of the signs under "When to get help" below apply to you.
Why it matters
Symptoms attributed to low testosterone overlap heavily with sleep apnoea, depression and thyroid disease, and the market for treatment substantially exceeds the need.
The numbers, in one place
| Measure | Figure |
|---|---|
| Testing | a morning blood sample, repeated to confirm |
| Common alternative explanations | sleep apnoea, depression, thyroid disease, anaemia |
| Associated with lower levels | obesity, poor sleep, heavy alcohol, some medicines |
| Effect of supplementation on fertility | suppresses sperm production, sometimes profoundly |
| Anabolic steroids | suppress the body's own production |
What helps
- Ask for the other causes to be excluded before attributing symptoms to testosterone
- Address sleep, weight and alcohol, all of which affect levels
- Have testing done in the morning and repeated before acting on it
- Tell your GP about any steroid or testosterone use, including past use
What to avoid
- Buying testosterone or anabolic steroids online
- Taking testosterone while trying to conceive
- Accepting treatment on the basis of a single test
Where to go next
- Why Testosterone Matters, Explained Simply
- The Testosterone Checklist: What to Do and What to Skip
- The Evidence on Men and Mental Health, Without the Hype
- What the Guidance Really Says About Male Pattern Hair Loss
When to get help
See a GP rather than self-treating for persistent fatigue, low libido, low mood or erectile dysfunction — these have many causes, several of which are more common and more treatable than low testosterone. Seek urgent help for chest pain, severe mood change, or signs of a blood clot if you are on testosterone therapy.
Where this comes from
How this page was put together
Every figure, recommendation and warning above is taken from the guidance named in Where this comes from. Nothing on this page is inferred, summarised or generalised beyond what those bodies publish: where they give a number, it is their number, and where they are silent, so are we. Pages are rebuilt whenever the underlying record changes. Sign-off by a named clinician, where it has happened, is shown at the top of the page along with the date.
Medical disclaimer
This article is general information, not medical advice. It cannot account for your own history, medication or circumstances. Always speak to a GP, pharmacist or another qualified health professional before making changes that affect your treatment, and never delay seeking medical advice because of something you have read here. In an emergency, call 999.