Oestrogen symptoms confuse people because too much and too little produce overlapping complaints. Fatigue, mood changes, poor sleep and weight change appear in both.
The pattern is what separates them.
High oestrogen relative to progesterone tends to show as heavy or prolonged periods, breast tenderness, bloating, mood swings concentrated before your period, and headaches that track your cycle.
Low oestrogen tends to show as hot flushes, night sweats, vaginal dryness, joint aches, thinning skin, and cycles that have lengthened or stopped.
Fluctuating oestrogen, which is what perimenopause actually is, produces both at different points in the same month. This is the pattern women find most bewildering, because they read about high oestrogen one week and low the next and recognise themselves in both.
The term is used loosely, and it is worth being precise.
It does not necessarily mean your oestrogen is high. It usually describes oestrogen being high relative to progesterone, which most often happens because progesterone has fallen rather than because oestrogen has risen.
That distinction matters, because progesterone typically declines several years before oestrogen does. A woman of forty-two with heavy periods and premenstrual anxiety often has normal oestrogen and falling progesterone.
It is also not a formal medical diagnosis, which is why testing for it is not straightforward.
Oestrogen varies enormously through a normal cycle and even more in perimenopause. A single blood test captures one moment.
This is why guidelines generally advise against routine hormone testing for women over forty-five with typical symptoms: the result cannot be interpreted reliably, and treatment is guided by symptoms instead.
Under forty-five, or where the picture is unclear, testing has more value, particularly to exclude other causes.
Two conditions mimic oestrogen problems closely and are settled by simple tests.
Thyroid function, with TSH, free T4 and free T3. Thyroid symptoms overlap almost completely with hormonal ones.
Ferritin. If your periods are heavy, iron depletion is likely and explains a great deal of the fatigue.
If bleeding has become heavy or irregular, that warrants investigation in its own right rather than being attributed to hormones.
Related reading: Oestrogen dominance explained · Low oestrogen symptoms · Signs of low progesterone · Should you test your hormones?
Educational only, not medical advice.