Perimenopause Fatigue: Why You're So Tired and What Actually Helps

Not All Fatigue Is the Same

Everyone tells you that perimenopause makes you tired. What nobody explains is that there are several different reasons this happens, and the reason matters enormously for what will help.

You can have fatigue from poor sleep quality caused by night sweats. You can have fatigue from cortisol dysregulation that makes you wired at the wrong times and crashed at others. You can have fatigue from iron deficiency or low ferritin, which heavy perimenopausal periods often cause. And you can have fatigue from thyroid disease, which is significantly more common in the perimenopause transition.

These four types of fatigue feel somewhat different from each other and respond to different interventions. Treating sleep-related fatigue with an iron supplement, or treating low ferritin with sleep hygiene, will not work. Getting the diagnosis right is the first step.

Type 1: Sleep-Disrupted Fatigue

The most common driver of perimenopausal fatigue is disrupted sleep architecture caused by night sweats, hot flashes, anxiety, and frequent waking. This is not just about total hours in bed. It is about whether you are reaching and maintaining the deep, slow-wave sleep where physical restoration happens, and the REM sleep where emotional and cognitive processing occurs.

Sleep-disrupted fatigue has a characteristic pattern: you feel worst in the morning, with some improvement as the day goes on. You tend to feel more alert in the late afternoon or early evening, which then makes falling asleep again harder. You may feel that coffee helps significantly but wears off quickly.

The path forward for this type is to address the sleep disruption itself, not to manage the fatigue downstream. Night sweat management (room temperature, bedding, trigger reduction), anxiety management (magnesium, wind-down routines, possibly progesterone), and CBT-I for any established insomnia patterns all address the root cause. Fatigue improves as sleep quality improves.

Type 2: Cortisol Dysregulation Fatigue

Cortisol follows a daily curve: high in the morning to support waking and alertness, declining through the afternoon, and reaching its lowest in the evening. When this pattern is disrupted, which perimenopause frequently does by altering HPA axis regulation, the result is fatigue at the wrong times.

Cortisol dysregulation fatigue often presents as: exhausted in the morning despite sleeping, a second wind that arrives around 9 or 10pm, crashing in the early afternoon, and feeling unrefreshed by even adequate sleep. The pattern is often described as wired but tired.

Strategies for cortisol fatigue focus on supporting the natural cortisol rhythm. Getting bright light exposure within 30 minutes of waking signals your brain to produce its cortisol peak at the right time. Eating breakfast with adequate protein within an hour of waking prevents the blood sugar crash that keeps cortisol artificially elevated. Avoiding caffeine before the cortisol morning peak (roughly before 9 or 10am for most people) allows the natural energy rise to occur. Adaptogens with the most clinical support for cortisol regulation include ashwagandha (KSM-66 extract, 300 to 600mg) and rhodiola rosea.

Type 3: Iron Deficiency and Low Ferritin

Heavy periods are very common in perimenopause, as irregular cycles and anovulatory bleeding can produce significantly heavier flow than in earlier reproductive years. This blood loss depletes iron stores, and iron deficiency produces fatigue that is often severe and unresponsive to sleep improvement or lifestyle changes.

The important nuance here is ferritin, not just hemoglobin. Standard CBC testing can show normal red blood cell counts while ferritin (the storage form of iron) is critically low. Ferritin under 50 ng/mL causes fatigue even when hemoglobin is technically within normal range. Many conventional ranges flag ferritin as low only below 12 or 15. For functional energy production and neurological function, 50 to 100 is a more useful target.

This means you need to specifically request a ferritin test, not just a standard hemoglobin or hematocrit. If your ferritin is low, iron supplementation (bisglycinate or liposomal forms are better tolerated than ferrous sulfate), dietary iron optimization (red meat, legumes with vitamin C, minimizing calcium at iron-containing meals), and addressing the underlying heavy bleeding pattern are all necessary.

Type 4: Thyroid-Related Fatigue

Autoimmune thyroid disease, particularly Hashimoto's thyroiditis, peaks in incidence during the perimenopause years. The symptoms of an underactive thyroid overlap almost completely with general perimenopause symptoms: fatigue, weight gain, hair thinning, cold intolerance, depression, constipation, brain fog, and joint pain.

Thyroid fatigue has several distinguishing features: the cold intolerance is often notable, with hands and feet especially cold. The fatigue tends to be constant rather than variable and does not improve meaningfully with any lifestyle intervention. Constipation that is new or worsening is more typical of thyroid disease than perimenopause alone. Eyebrows thinning at the outer third is a classic but not universal sign.

Standard TSH testing alone misses a meaningful proportion of thyroid dysfunction. Ask for a full thyroid panel including free T3, free T4, and TPO antibodies. If antibodies are elevated even with normal TSH, you have autoimmune thyroid disease that needs monitoring and may eventually need treatment. Many clinicians treat symptoms of hypothyroidism even with borderline-normal TSH when antibodies are positive and symptoms are significant.

Lab Values Worth Checking

If your fatigue is significant and unresponsive to sleep and lifestyle improvements, a targeted blood panel will help distinguish the cause. Useful tests include: complete blood count, ferritin, full thyroid panel (TSH, free T3, free T4, TPO antibodies), fasting glucose and insulin, vitamin D (25-OH-D, with 40 to 60 ng/mL as a functional target, not just "normal"), B12, magnesium RBC (serum magnesium misses intracellular deficiency), and a basic metabolic panel.

Bringing specific fatigue symptoms to your provider with a request for this panel is a reasonable and specific ask. If fatigue is severe, long-standing, or accompanied by post-exertional malaise (worsening after activity), a more comprehensive workup for other conditions is warranted.

Many women in perimenopause have multiple simultaneous deficiencies. Low ferritin, low vitamin D, and borderline thyroid function occurring together are common. Addressing one without the others produces partial improvement at best.

What Worsens Perimenopause Fatigue

Over-exercising is a real and common mistake in perimenopause fatigue management. Intense daily exercise without adequate recovery raises cortisol and further suppresses already fragile sleep. Many people respond to fatigue by pushing harder physically, which depletes the system further. Signs that you are over-exercising: you feel worse after workouts rather than better, your resting heart rate is elevated, and you are more tired on exercise days than rest days.

Skipping meals drives blood sugar variability and cortisol spikes that create energy crashes. Eating three meals with adequate protein (25 to 40 grams each) at consistent times supports more stable energy throughout the day. Skipping breakfast specifically is associated with worse cortisol dysregulation patterns in perimenopause.

Alcohol reliably worsens fatigue in this life phase. It fragments sleep in the second half of the night, raises cortisol, depletes B vitamins and magnesium (all relevant to energy production), and directly suppresses mitochondrial function. Many people find their fatigue improves meaningfully within two weeks of removing alcohol.

Adaptogens With Actual Evidence

The adaptogen market is enormous and largely unregulated. A few compounds have meaningful clinical evidence for fatigue specifically.

Ashwagandha (specifically the KSM-66 extract, studied at 300 to 600mg daily) has multiple randomized controlled trials showing reduced fatigue, improved sleep quality, and reduced cortisol in stressed adults. The effect is not stimulant-like. It is a gradual normalization of the stress response over four to eight weeks.

Rhodiola rosea has evidence for mental fatigue, particularly for fatigue-driven cognitive symptoms like difficulty concentrating and slowed thinking. It appears to work by supporting mitochondrial energy production and reducing the cortisol response to stress. It should be taken in the morning, not at night, as it can be mildly activating.

CoQ10 supports mitochondrial energy production and may be particularly relevant in perimenopause because estrogen normally supports CoQ10 levels. Levels tend to decline with age and with statin medication use. The ubiquinol form is better absorbed than ubiquinone. Evidence is stronger for fatigue associated with statin use or with mitochondrial inefficiency than for general fatigue. PeriPlan lets you track energy levels daily alongside sleep and exercise, which helps you see which interventions are actually moving the needle for your specific situation.

Building Your Energy Back

Perimenopausal fatigue is often layered, meaning multiple causes are operating simultaneously. Starting with the most common and most treatable, which is sleep disruption and ferritin status, and systematically working through the others gives you the best chance of meaningful recovery.

Expect the process to take weeks to months, not days. The physiology that produced the fatigue has been operating for a while. The restoration also takes time. Tracking your energy on a simple one-to-ten daily scale reveals progress that is often invisible in the moment but clear over a month or two of data.

Fatigue is one of the most undertreated symptoms in perimenopause because it is often dismissed as normal for your stage of life. It is common, but common does not mean you simply have to accept it. With the right evaluation and targeted interventions, most people can meaningfully improve their energy during this transition.

This content is for informational purposes only and does not replace medical advice. Always consult your healthcare provider about your specific situation.