What it measures
- Oestradiol (E2)
What is oestradiol?
Oestradiol is the most active form of oestrogen. It drives the growth of the womb lining each month and affects your bones, skin, mood and heart health. Levels rise and fall through your cycle and fall after the menopause.
Measured early in the cycle, oestradiol helps interpret your FSH result: a high early oestradiol can make FSH look falsely normal. It’s also included in our Fertility Package and Perimenopause Profile.
Who it’s for
- Irregular or absent periods
- Fertility investigations
- Perimenopause symptoms
- Monitoring HRT, if your doctor advises
How to prepare
- Drink plenty of water beforehand; it makes the sample quicker and easier to take.
- You don’t need to fast.
- If you have periods, book for day 2–5 of your cycle (day 1 is the first day of bleeding).
- Stop biotin (vitamin B7) supplements 48 hours before, as biotin can affect hormone and thyroid results.
Oestradiol Blood Test: your questions
When should I have an oestradiol test?
Usually on day 2–5 of your cycle, alongside FSH and LH, unless your doctor has asked for a different day.
Information on this page is general and doesn’t replace advice from your GP, midwife or consultant. If you feel unwell or are worried about symptoms, contact your GP, call NHS 111 or, in an emergency, 999.