What it measures
- Total testosterone
Who it’s for
- Low sex drive or erection problems
- Tiredness, low mood or poor concentration
- Losing muscle strength or gaining body fat
- Monitoring testosterone treatment
Testosterone and age
Testosterone falls gradually from around your 30s or 40s, by less than 2% a year. Most men stay within the normal range, but excess weight, type 2 diabetes, poor sleep, heavy drinking, long-term stress and some medicines can push it lower. Low testosterone is diagnosed from symptoms together with consistently low results, so a low reading is usually repeated.
Why the time of day matters
Testosterone is highest in the morning and falls through the day, so a late-afternoon test can look low when it isn’t. Book before 11am for a result that can be compared with standard ranges. Being unwell, or a run of very poor sleep, can also lower it temporarily.
| Total testosterone (nmol/L) | What it usually means |
|---|---|
| Below 8 | Low, especially with symptoms (confirmed on a repeat morning test) |
| 8 to 12 | Borderline: SHBG and free testosterone help interpret it |
| Above 12 | Generally normal |
How to prepare
- Book a morning appointment, ideally before 11am, when levels are highest.
- Stop biotin (vitamin B7) supplements, often found in hair, skin and nail products, 48 hours before.
- No fasting needed. Eat and drink as normal.
- If you’ve been unwell recently, wait until you’ve recovered.
How it works at our Croydon clinic
Book online
Choose your test and a time that suits you. No GP referral needed.
A 15-minute visit
A trained clinician takes a small blood sample at 169 Shirley Road, Croydon. Tell us if you’re nervous.
Results in 1–3 days
A clear report showing each result against its reference range.
Next steps
Share your report with your GP, who can arrange NHS follow-up if anything needs it.
Questions
Should I test SHBG too?
If your total testosterone is borderline, SHBG helps work out how much is active. Many men book our SHBG test (£79) at the same visit.
I’m on testosterone treatment. When should I test?
Follow the timing your prescriber has given you, as it depends on the type of treatment, and tell us when you last used it.
How much is a Testosterone Test in Croydon?
£70 at our clinic at 169 Shirley Road, Croydon, including taking your blood sample and your report.
How quickly will I get my results?
Usually within 1 to 3 days, in a clear report showing each result against its reference range.