Before you use this guide
This is general information, not a diagnosis or a substitute for care from a clinician who knows your medical history. Seek urgent help for severe or rapidly worsening symptoms.
When testosterone testing may be useful
Possible testosterone deficiency can involve reduced libido, erectile difficulties or loss of morning erections. Other features may include low mood, fatigue, reduced strength, anaemia or low bone density, but these are non-specific and commonly have other causes.
A diagnosis of male hypogonadism requires a compatible clinical picture and biochemical evidence. A test ordered without considering symptoms is more likely to be misleading.
Timing and preparation matter
Testosterone follows a daily rhythm and may be temporarily lowered by food intake, poor sleep or illness. Society for Endocrinology guidance advises measuring total testosterone fasting before 11am, preferably after a good night’s sleep and not during an acute illness.
Shift work and disrupted sleep can change the usual rhythm, so tell the clinician when you normally sleep and wake. Follow the instructions supplied for your appointment.
Why one low result is not enough
A result below the laboratory reference range is generally repeated on a different morning before a diagnosis is made. Testosterone varies within the same person, and temporary factors can suppress it.
If a result is borderline or inconsistent with symptoms, sex hormone-binding globulin may help estimate free testosterone. LH, FSH and prolactin can provide information about possible causes when clinically indicated.
Do not self-treat a result
Testosterone treatment is not an appropriate response to tiredness alone or a single private result. Treatment decisions require confirmation, assessment of the cause, discussion of fertility and other risks, and ongoing monitoring.
Non-hormonal factors such as sleep, weight, alcohol, stress, mental health, medication and other medical conditions may contribute to symptoms and should not be overlooked.
Before booking a hormone profile
- Identify the symptoms you want investigated and how long they have been present.
- Choose a morning appointment and follow fasting instructions.
- Avoid testing during an acute illness where possible.
- List prescribed medicines, supplements and anabolic steroid use honestly.
- Plan for clinical review and repeat confirmation if the result is low.
Common questions
Questions about this topic.
Guidance generally recommends a fasting morning sample before 11am, although sleep patterns and individual circumstances should be considered.
Sources and further reading
We use authoritative UK guidance and patient information. External sources may be updated after this guide is published.
