Why You're So Tired in Perimenopause
← Back to Learn · By Kathryn Carter · Last updated: 16 August 2026
There's tired, and then there's perimenopause tired.
The second one doesn't lift after a good night's sleep, doesn't correlate with how much you did that day, and tends to arrive with a flatness that's hard to describe to anyone who hasn't had it.
It's one of the most commonly reported changes of perimenopause and one of the least discussed. Here's what's driving it — and, just as importantly, what else to rule out.
Why energy drops in perimenopause
Sleep is fragmented even when it's long enough. Night sweats and 3am waking break sleep into pieces. Fragmented sleep is far less restorative than continuous sleep of the same duration, so you can spend eight hours in bed and wake unrefreshed. This is the single biggest driver for most women. More on menopause and sleep.
Progesterone and oestrogen are both moving. Progesterone calms the nervous system; oestrogen influences serotonin and temperature regulation. When both fluctuate unpredictably — which is what perimenopause is — the nervous system spends more effort on regulation and less is left over.
Cortisol timing shifts. The curve that should rise before you wake and fall through the evening often flattens. That's the "tired but wired" feeling: exhausted at 3pm, alert at 11pm.
Muscle mass is declining. Less muscle means less capacity for the same physical work, so ordinary days cost more than they used to.
Iron may be part of it. This one gets missed constantly. Perimenopause often brings heavier and more erratic periods, and heavy bleeding is a common cause of iron deficiency in women in their forties. Iron deficiency causes exactly this kind of fatigue, and it's testable and treatable. More on heavy periods in perimenopause.
Work out which kind of tired you have
Most articles give you a list of causes. More useful is a way of telling them apart, because the fix is different for each.
If you wake unrefreshed no matter how long you sleep — this is likely sleep-driven. Night sweats, snoring, or frequent waking are the things to address first. Fixing sleep fixes this kind of fatigue in a way that nothing else will.
If you're tired all day with no clear pattern, and you also feel breathless on stairs, cold, or notice hair shedding — ask your GP about iron studies and thyroid function. Both are common in midlife women, both cause fatigue, and both are straightforward blood tests.
If your energy crashes mid-afternoon and lifts after eating — look at how your meals are built. Meals light on protein and fibre produce sharper blood-sugar swings, and the trough is often what you're feeling at 3pm.
If you feel flat rather than tired — low motivation, low interest, low mood — that's worth a conversation with your GP rather than a supplement. Mood changes are common in perimenopause and there are effective options.
If it's diffuse and long-running — the useful frame is that several of these are usually happening at once, and you don't have to fix them in order. Start with sleep, get bloods done, and build meals better.
What actually helps
Protect sleep first. Everything else is easier from a better baseline.
Eat protein at breakfast. Steadier energy through the morning, and most women are well short here. How much protein you need after 40.
Move, even when you don't want to. Counterintuitive when you're exhausted, but regular moderate movement reliably improves energy in the medium term. Start smaller than feels worthwhile.
Get your bloods done. Iron studies, thyroid function, vitamin D and B12. Ask specifically — fatigue in a woman over 40 is sometimes waved through as "just menopause" when it's something testable.
Look at alcohol. It fragments the second half of the night, which is already the fragile half.
Reduce what you can. Perimenopause often arrives at the busiest possible life stage. That's not a personal failing and some of it is genuinely negotiable.
When to see your GP
Book an appointment if fatigue is persistent or getting worse, if you have heavy periods, if you snore or wake gasping, if you feel breathless on exertion, or if low mood is part of it. Fatigue has many causes and most of the common ones are testable.
Where MyPause fits
Hormone Balance Plus (AUST L 470807) is a listed medicine formulated for women through the menopause transition. It contains vitex, peony, maca, American ginseng, rhodiola, withania, passionflower, lemon balm and magnesium.
- Relieves weariness, tiredness, fatigue and feelings of weakness in healthy individuals
- Helps maintain and support energy levels and energy production
- Helps maintain and support cognitive function and mental function
- Contains herbs traditionally used in Western herbal medicine as an adaptogen to help the body adapt to stress
- Contains herbs traditionally used in Western herbal medicine to support a healthy stress response in the body
Always read the label and follow the directions for use. If symptoms persist, talk to your health professional.
Warning: Vitex agnus-castus may affect hormones and medicines such as oral contraceptives. Consult your health professional before use.
Women's B Energy Complex (AUST L 471005) is a B-vitamin complex that helps maintain and support energy levels and energy production, helps convert food into energy, and helps maintain and support nervous system health and function. Vitamins can only be of assistance if dietary intake is inadequate.
Warning: stop taking this medication if you experience tingling, burning or numbness and see your healthcare practitioner as soon as possible. Contains vitamin B6.
Explore Hormone Balance Plus → · Explore Women's B Energy Complex →
Common questions
Why am I so tired during perimenopause?
Usually several things at once: fragmented sleep from night sweats or 3am waking, fluctuating oestrogen and progesterone, shifting cortisol timing, and sometimes iron deficiency from heavier periods. Sleep is the biggest single driver for most women.
Is extreme tiredness a sign of perimenopause?
Fatigue is commonly reported in perimenopause, but it isn't specific to it. Iron deficiency, thyroid problems, sleep apnoea and low mood all cause similar fatigue and are all more common in midlife. Worth testing rather than assuming.
How long does perimenopause fatigue last?
It varies. Many women find energy improves as hormone levels stabilise after menopause, particularly if sleep settles. It isn't something you simply have to wait out — sleep, iron status and meal structure are all worth addressing.
What helps with menopause fatigue?
Protecting sleep, adequate protein, regular moderate movement, moderating alcohol, and ruling out iron deficiency and thyroid problems with your GP.