Guidance for men
Fast for at least 8 hours before collecting your sample.
Take the test first thing in the morning, ideally between 7am and 10am, before breakfast.
Morning testing is important because testosterone levels naturally peak at this time.
Collect and post your sample on the same day, Monday to Thursday.
Do not collect or post it on a weekend or bank holiday.
Guidance for women
Take your sample during the morning. The exact time is less important than it is for men.
If you have regular periods, test on day 2 to day 5 of your cycle, ideally day 3. Day 1 is the first day of bleeding.
If your periods are irregular, aim to test as close to day 3 as possible.
If you do not have periods, you can test on any day.
Collect and post your sample on the same day, Monday to Thursday.
Do not collect or post it on a weekend or bank holiday.
Following this guidance helps your sample reach the lab in good condition and gives the clearest picture of your hormone levels.