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Reproductive Health

Estradiol (E2)

Oestradiol is the main female sex hormone. It naturally rises and falls through the monthly cycle and settles to a lower level after menopause, so there is no one "normal" number — what counts as a healthy result depends on where you are in your cycle and your stage of life. Your result is read against the range on your report for your cycle phase.

Targeted Testing
CategoryReproductive Health
Reference rangeSee your report
Evidence○Targeted Testing
Last updated3 July 2026
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What is estradiol (e2)?

Oestradiol (also written estradiol, abbreviated E2) is the most potent form of oestrogen — the group of hormones primarily responsible for the development of female sex characteristics and for regulating the menstrual cycle. In women, the pituitary gland (a pea-sized gland at the base of the brain) releases follicle-stimulating hormone (FSH), which stimulates cells in the ovaries to grow egg follicles and produce oestradiol. When oestradiol rises to a certain level, the pituitary releases a surge of luteinising hormone (LH) that triggers ovulation — the release of an egg. Oestradiol also supports healthy bone density and cholesterol levels, and plays a role in mood and cognitive function. Small amounts of oestradiol are present in males as well, where it is produced mainly by conversion from testosterone.

Why is it tested?

Oestradiol is tested when there are symptoms that might relate to the menstrual cycle or ovarian function — irregular or absent periods, trouble conceiving, menopausal symptoms, or unexplained changes in mood or bone health. One important nuance: menopause is usually diagnosed clinically (based on symptoms and age) rather than by a single oestradiol result. Routine measurement of oestradiol for menopause diagnosis is of limited value on its own, and the test is most useful when ordered alongside other hormones such as FSH and progesterone to build a fuller picture of ovarian function. Because oestradiol rises and falls so much across the cycle, the cycle day on which the sample is taken matters a great deal for interpretation.

Reference range (Australia)

No single 'normal' value — oestradiol changes across the menstrual cycle and life stage; use the reference interval printed on your report for your cycle phase pmol/L

Oestradiol rises and falls substantially through the menstrual cycle. Levels are highest mid-cycle before ovulation and lowest during the period. After menopause, levels drop to a persistently low range. The relevant comparison is the phase-specific reference interval printed on your own report, not a single number.

Reference intervals vary between laboratories. Always use the range printed on your own report.

What your result means

If your level is low

Oestradiol is naturally lowest during your period. A low result in the follicular phase (the first half of your cycle) or after menopause may simply reflect normal physiology. If you are reading this worried about early menopause, it is worth knowing a single oestradiol on its own does not diagnose that. The cycle day matters enormously, and your GP looks at the whole pattern over time, not one number. A persistently low result alongside symptoms such as irregular periods, bone concerns, or menopausal symptoms is worth raising with your GP, who will consider the full hormone picture. Cycle timing and life stage are essential context.

If your level is in range

A result within the phase-specific reference interval on your report suggests oestradiol is in the expected range for where you are in your cycle and your life stage. If symptoms prompted the test, a normal oestradiol is useful information — worth discussing with your GP in context of your other results.

If your level is high

Oestradiol is highest naturally in the middle of your cycle, just before ovulation. A high result needs to be read against where you are in your cycle — a mid-cycle peak is expected and normal. Outside of that mid-cycle window, a result above the range on your report is worth discussing with your GP, who will look at it alongside your cycle history, FSH, and LH. A single elevated result does not diagnose a condition.

What can affect your result

The biggest driver of oestradiol is cycle phase. Levels climb steadily through the first half of the cycle, peak around mid-cycle to trigger ovulation, then fall and rise again modestly in the second half (the luteal phase) before dropping again at the start of the next period. After menopause, oestradiol settles at a consistently lower level. Hormonal contraceptives — pills, patches, implants, or hormonal intrauterine devices — suppress natural oestradiol production or introduce synthetic oestrogen, which changes how results should be interpreted. Pregnancy raises oestradiol substantially. Body weight, liver function, thyroid function, and some medicines can also affect the level. Significant stress or rapid weight change can disrupt the hormonal rhythm and shift oestradiol.

When to act

If your result is outside the range printed on your report for your cycle phase, it is worth a conversation with your GP rather than a cause for alarm. The cycle day the sample was taken is one of the most important pieces of context. Your GP may suggest a repeat test on a specific day, or order related hormones (FSH, LH, progesterone) to build a complete picture. This page is general information and is not a substitute for advice from your GP.

Frequently asked questions

There is no single normal number — oestradiol changes dramatically across the menstrual cycle. Levels are highest in the middle of your cycle, just before ovulation, and lowest during your period. After menopause, levels fall and stay low. The relevant comparison is always the phase-specific reference interval printed on your own report; your GP uses that to interpret your result in the context of when in your cycle the sample was taken.

Oestradiol rises from the start of the cycle, peaks around ovulation to trigger the release of an egg, then falls and rises again modestly in the luteal phase before dropping at the next period. The same absolute number can be completely normal at one point in the cycle and outside the expected range at another. This is why your GP will typically ask what day of your cycle the sample was taken, and why testing on a specific day is often recommended.

Usually not on its own. Menopause is typically diagnosed clinically — based on symptoms and the pattern of periods stopping — rather than by a single oestradiol result. Routine measurement of oestradiol for menopause diagnosis is of limited value, and in situations where the diagnosis is uncertain, FSH is generally the more informative test. Your GP can explain which tests make sense for your circumstances.

High oestradiol is expected naturally mid-cycle before ovulation — that peak is what drives the egg release. Outside that mid-cycle window, a high reading is worth discussing with your GP alongside your cycle history. Low oestradiol is normal during your period and after menopause. Hormonal contraceptives, body weight, liver health, thyroid function, stress, and certain medicines can all shift oestradiol. Cycle timing is always the most important context.

Yes, in small amounts. Oestrogens — including oestradiol — are the primary female sex hormones but are present in males too. In men, oestradiol is produced mainly by conversion from testosterone. Oestradiol testing in men is less common but may be relevant in specific clinical situations your GP can explain.

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