Unpacking Perimenopause: What Is Happening to Your Hormones and Body

Article Snapshot (AI Generated)

  • Perimenopause is the transition before menopause, when ovulation becomes less consistent and hormone patterns become more unpredictable.
  • Oestrogen does not simply decline in a straight line. It can rise and fall from month to month, while progesterone often becomes lower or less reliable because ovulation is less consistent.
  • This shifting oestrogen/progesterone pattern can explain why symptoms feel random: heavier bleeding, breast tenderness or irritability in one cycle, then hot flushes, night sweats, vaginal dryness or poor sleep in another.
  • FSH and LH are brain messenger hormones that try to keep the ovaries responding. Because the ovaries respond less predictably during perimenopause, these markers can also fluctuate.
  • The first clue is often a period change, but symptoms can also include sleep disruption, anxiety, brain fog, fatigue, libido changes, vaginal dryness, joint pain and body composition changes.
  • A single hormone blood test often does not tell the full story. Symptoms, cycle history and broader health markers usually give more useful context.
  • The best support plan looks at the whole system: sleep, stress, nutrition, blood glucose, muscle, bone health, alcohol intake, medications, medical history and whether MHT or other treatments are appropriate.

Perimenopause feels like your body has changed the rules without telling you.

One month your cycle is predictable, the next, your period is early, late, heavier, lighter, or missing altogether.

Your sleep becomes lighter, anxiety is louder, and you notice brain fog, night sweats, low libido and intolerance to stress.

This all being said, Perimenopause is a normal part in the transition into menopause.

In this article, we’ll unpack further what perimenopause is. We’ll discuss the stages from perimenopause into menopause, how it affects quality of life and some tips of what we can do manage it.

What Is Perimenopause?

Perimenopause is the transition leading up to menopause.

Women are considered to have reached menopause once you have gone 12 months without a period, assuming there is no other medical reason for the bleeding change.

Perimenopause is the lead-up to that point, when ovarian function becomes less consistent and hormone patterns become more variable.

A Simple Way to Understand Oestrogen and Progesterone

Two key hormones involved in this transition are oestrogen and progesterone.

Oestrogen is often thought of as the hormone that supports the first half of the menstrual cycle. It helps build the uterine lining, supports vaginal and urinary tissues, influences mood, temperature regulation, skin, bones, blood vessels and brain function.

Progesterone is mainly made after ovulation. It helps balance the second half of the cycle, supports a calmer nervous system, helps regulate bleeding patterns and can influence sleep, mood and fluid retention.

During perimenopause, oestrogen does not simply fall in a straight line. It can rise and fall unpredictably. Progesterone often becomes lower or less consistent because ovulation becomes less reliable. This can create a feeling of hormonal imbalance: some months may feel like high-oestrogen symptoms, such as heavier bleeding, breast tenderness or irritability, while other months may feel more like low-oestrogen symptoms, such as hot flushes, night sweats, vaginal dryness or poorer sleep.

So when people say hormones are “declining,” it is only part of the story. Perimenopause is better understood as a time of fluctuating oestrogen and less reliable progesterone, before the lower-oestrogen pattern of menopause becomes more established.

When Does Perimenopause Affect Women?

Perimenopause usually begins between ages of 45 to 56 years of age and may last around 4 to 8 years (Peacock & Ketvertis, 2023). Some women move through it with minimal disruption. Others have symptoms for years.

A better way to think about the whole picture is in phases:

  • Early perimenopause: cycles may still come regularly, but they start to change. The luteal phase may shorten, PMS may worsen, sleep may become more fragile, and breast tenderness or heavier bleeding may appear.
  • Mid perimenopause: cycles become more obviously variable. Ovulation may be inconsistent, bleeding can become heavier or less predictable, and symptoms such as hot flushes, night sweats, anxiety and brain fog can become more noticeable.
  • Late perimenopause: cycles may be more than 60 days apart. Oestrogen may be lower more often, FSH may trend higher, and classic menopause symptoms may become stronger.
  • Menopause and postmenopause: menopause is reached after 12 months without a period. Postmenopause is the stage after that.

The First Sign = Period Changes

Usually, the most reliable clue we see to determine perimenopause is changes in your menstrual cycle.

Of course, there are many other reasons why your cycle could be irregular, but this is often the first clue, assuming you’re within the age range (or close to it).

Common menstrual cycle signs include periods becoming irregular, shorter or longer than usual, lighter or heavier than usual, or absent for a few months (Jean Hailes for Women’s Health, 2026.).

Some examples include:

  • cycles becoming shorter, sometimes 25 days or less
  • cycles becoming longer or more spread out
  • heavier bleeding than usual
  • lighter bleeding than usual
  • spotting or unpredictable bleeding
  • more painful periods
  • worse PMS, breast tenderness or irritability
  • occasional skipped periods

One common trap is assuming perimenopause only starts when periods become very irregular, but symptoms can start when cycles still look fairly regular.

While again, a lot of things can contribute to cycle irregularity (such as busy life, high stress or poor diet), it can be easily to blame these and overlook perimenopause all together.

The Unpredictable Nature of Hormones in Perimenopause

Perimenopause is not simply a smooth decline in oestrogen.

Oestrogen fluctuates. Progesterone often becomes less consistent as ovulation changes. Follicle-stimulating hormone (FSH) and luteinising hormone (LH) can also shift as the brain tries to keep the ovaries responding. Some cycles are ovulatory. Some are not.

FSH and LH are messenger hormones from the brain. FSH helps stimulate follicles in the ovaries, while LH helps trigger ovulation. During perimenopause, the ovaries may not respond as predictably as they once did, so the brain can send stronger or more variable signals. This is one reason FSH can look higher in one cycle and lower in another, and why a single blood test may not tell the full story (Hechtman, 2025)..

This leads to some months feeling almost normal, then the next month you feel completely derailed.

This is also why perimenopause can feel a little bit random, because you can have:

  • a normal-looking period but poor sleep
  • heavy bleeding and breast pain one month, then a skipped period later
  • anxiety without hot flushes
  • brain fog before obvious cycle disruption
  • night sweats mainly before your period

Common Perimenopause Symptoms

Perimenopause symptoms can be physical, emotional, cognitive, metabolic and sexual.

Common symptoms include:

  • hot flushes
  • night sweats
  • broken sleep or waking at 2-4 am
  • fatigue
  • headaches or migraines
  • breast tenderness
  • heavier or irregular bleeding
  • vaginal dryness
  • urinary urgency or recurrent irritation
  • lower libido
  • mood swings and low mood
  • anxiety or a reduced tolerance to stress
  • irritability or rage
  • brain fog
  • muscle aches or joint pain
  • changes in body composition
  • increased abdominal weight gain

Perimenopause and menopause affect women differently, with symptoms ranging from hot flushes and sleep problems to anxiety, brain fog and changes to mental health and wellbeing (Australian Government Department of Health, Disability and Ageing, 2026).

Progesterone Often Drops Before Oestrogen

One of the most useful things to understand is progesterone.

Progesterone is mainly produced after ovulation. If ovulation becomes less consistent, progesterone production can become less consistent too. You can still have oestrogen activity, but less progesterone to balance the second half of the cycle.

This can contribute to symptoms such as:

  • heavier bleeding
  • breast tenderness
  • worse PMS
  • anxiety
  • irritability
  • sleep disruption
  • night sweats
  • migraines
  • shorter cycles

Perimenopause is a time when cycles may still be present, but luteal phase changes and lower mid-luteal progesterone can contribute to poorer stress tolerance, anxiety, sleep disurbances, breast pain and heavier bleeding (Skilton, 2026).

In plain English: you may still be cycling, but the quality and rhythm of ovulation can change. When ovulation changes, progesterone changes. When progesterone changes, the nervous system often feels it.

Should I Do Hormone Testing?

Yes and no.

For most women in the expected age range, perimenopause is assessed through symptoms, age and cycle changes. Jean Hailes notes that if you are between 45 and 55, it is not usual for a doctor to measure hormone levels to diagnose perimenopause; symptoms and period changes are usually more useful (Jean Hailes for Women’s Health, 2026).

That can be frustrating if you want a clear answer from a blood test. But it makes sense clinically. FSH, oestradiol and progesterone can vary across the cycle and across different months. A single blood test might catch one moment, not the whole transition, a blood test can be almost useless.

Testing may still be useful when:

  • symptoms start early (Much further before age 45)
  • periods stop much earleir too.
  • Strange, unusual or severe symptoms that are ongoing
  • bleeding is heavy, prolonged or unpredictable
  • pregnancy is possible
  • thyroid disease, iron deficiency, B12 deficiency, vitamin D deficiency, diabetes or other conditions need to be ruled out
  • there is a history of chemotherapy, radiotherapy, ovarian surgery or hysterectomy

A better approach for hormone testing is actually through dried urine, saliva and serum testing, often known as a DUTCH test.

This usually involves multiple collection across a 24-hour period to better understand sex and adrenal hormonal patterns, which can often better help the clinical picture (Hechtman, 2025).

Heavy Bleeding and Perimenopause

Some bleeding changes are common in perimenopause. That does not mean all bleeding changes are harmless.

Always speak to your GP if you experience the following over a consistent basis:

  • very heavy bleeding
  • bleeding that lasts longer than usual
  • bleeding between periods
  • bleeding after sex
  • bleeding after menopause
  • pelvic pain
  • unexplained weight loss
  • dizziness, faintness or symptoms of iron deficiency

Healthdirect recommends medical review if perimenopausal symptoms are bothering you or affecting daily life, and specifically flags heavy bleeding, bleeding between periods and bleeding after sex as reasons to see a doctor (Healthdirect, n.d.).

Heavy bleeding can also contribute to low iron, which can worsen fatigue, breathlessness, restless legs, poor exercise tolerance, hair shedding and low mood. If bleeding has changed significantly, iron studies are often worth discussing.

The Stress Picture

Perimenopause and the ovaries have a substantial link to the brain and nervous system.

The hypothalamic-pituitary-ovarian (HPO) axis is the communication loop between the brain and ovaries. The hypothalamic-pituitary-adrenal (HPA) axis is the communication loop between the brain and adrenal stress response. These systems are connected. Sleep loss, under-eating, overtraining, psychological stress, alcohol, blood sugar swings and chronic illness can cause dysregulation across both these systems.

This point is critical, because often perimenopause symptoms are worsened because when our HPO/HPA Axis is burdened by these factors.

Symptoms such as feeling tired but wired, extreme insomnia or very poor stress resilience become amplified.

Sleep, stress management, circadian rhythm, nutrition and movement are core foundations for supporting the HPA/HPO axis, which in return supports an easy transition into menopause (Skilton, 2026).

The takeaway: If your sleep is broken, your blood glucose is swinging, your caffeine is high, your alcohol intake is creeping up and your training is either too intense or non-existent, perimenopause may feel much worse than it needs to.

Food and Perimenopause

There is no single perimenopause diet, yep, I said it.

There is more key factors to consider when going through perimenopause to implement into (or out of) your current diet.

Some core examples include:

  • enough protein at each meal (This will support your mood, hormones and nervous system in general)
  • fibre-rich carbohydrates such as vegetables, legumes, oats, wholegrains, fruit and root vegetables where tolerated (Think gut health, which also supports mood!)
  • healthy fats from olive oil, avocado, nuts, seeds, eggs and oily fish
  • eat regular meals and do not skip them, this will worsen your anxiety and cravings
  • regular meals if skipping food worsens anxiety, cravings or night waking
  • Eat enough food in general, especially if you are highly active or training intensively
  • reduced alcohol if sleep, hot flushes, mood or weight gain are concerns
  • reduce ultra-processed foods, this increases inflammation and worsens symptoms

If you want it in basic terms, the best approach is eating adequate protein, quality carbohydrates and fat, and limit aggressive dieting.

Protein supports blood glucose stability, thyroid health, lean mass and the amino acid supply needed for hormone-related processes. Carbohydrates can matter too, because low energy availability and low glucose availability may affect LH signalling and ovulation in susceptible women (Skilton, 2026).

This is pretty important. Many midlife women I see respond to body changes by eating less, fasting a lot and pushing 110%. You might move the needle a little bit, but usually, this worsens sleep, stress hormones, cravings and cycle disruption.

For related reading:

Movement and Perimenopause

Perimenopause is a key time to protect muscle and bone, and we can do this through movement.

I know we’re not all on the same level when it comes to exercise motivation, but perimenopause is a pinnacle time where changes happen (and movement becomes important).

Oestrogen changes can affect bone turnover, connective tissue, joint comfort, insulin sensitivity and where body fat is stored. RACGP notes that menopause is associated with reduced bone mineral density and changes in cardiovascular risk factors such as increased central adiposity (Magraith & Jang, 2026).

Research also suggests late perimenopause may be a vulnerable period for skeletal muscle loss. Park et al. found appendicular lean mass was lower in late compared with early perimenopausal women, with FSH proposed as one possible contributor (Park et al., 2020).

Some simple tips to think of movement in your daily routine:

  • Move often and daily, on the hour every hour is good if you have an office job
  • Walk after your lunch break to support healthy blood sugar regulation
  • If possible, incorporate light weights or bodyweight training 20-30 minutes, 2-3 times a week.
  • If difficult, find one single addition you can sustain and repeat daily. This could be just 10-15 minutes of walking, anything extra counts.
  • support vitamin D and calcium status where needed
  • address sleep and alcohol intake
  • avoid long periods of under-eating
  • treat pain or injury properly so you can keep moving

Of course, when it comes to bone, we also need to consider our vitamin D and calcium status, and avoid long periods of under-eating.

For related reading, see Creatine: What It Is, How It Is Used and Why Brain Health Research Is Getting Interesting, Magnesium: Why This Mineral Matters for Energy, Stress, Sleep and the Nervous System and Zinc: Why It Matters for Immunity, Recovery and Overall Health.

Sleep and Perimenopause

Poor sleep can make almost every perimenopause symptom feel worse.

Night sweats can wake you. Anxiety can wake you. Alcohol can fragment sleep. Low blood glucose overnight can wake some people. Stress can make the nervous system more alert when it should be downshifting.

This often flows into the next day, making everything louder, cravings worsen, and mood less steady.

You tend to then drink more coffee, become susceptible to poor food choices, and the list goes on.

So, it’s always good to have a sleep plan to mitigate some of the effects, and support your nervous system as best you can.

Of course, other tailored treatment plans, supplements and herbal medicine can help here too (book a free discovery call to learn how).

Some realistic tactics to support your nervous system (and sleep) might include:

  • 10-15 minutes morning sunlight to better regular your circadian rhythm
  • Setting a consistent wake and bed time (while limiting phone use)
  • caffeine before midday
  • enough food during the day (esp. protein!)
  • alcohol reduction, especially close to bedtime
  • a cooler bedroom
  • A sleep wind down ritual (maybe it’s a tea and reading before bed).

For deeper sleep context, see Sleep Hygiene: What It Is and How to Build Better Sleep Habits and Morning Sun and Circadian Rhythm: Why Light Timing Matters for Sleep, Energy and Mood.

Where Does MHT Fit?

Menopause hormone therapy, or MHT, can be very helpful for some women.

It is not the only option, and it is not automatically suitable for everyone. But it should not be dismissed out of fear either.

RACGP notes that MHT can be offered to symptomatic women where there are appropriate clinical indications and no contraindications, after an individualised discussion about risks and benefits (Magraith & Jang, 2026). It may help symptoms such as hot flushes, night sweats, sleep disturbance and genitourinary symptoms, and it can also have a role in bone health for some women.

The decision depends on your symptoms, age, menstrual stage, uterus status, bleeding pattern, migraine history, cardiovascular risk, clotting history, breast cancer risk, liver health, medications and personal preferences.

This is something you can discuss with your GP, but not something helped with naturopathically. Of course, if you are going through MHT, we can support alongside.

A Practical Start to Perimenopause

If you suspect perimenopause, start with a simple three-month snapshot.

Track the following if you can:

  • cycle length, bleeding volume and duration
  • night sweats or hot flushes (frequency per week, severity)
  • sleep quality (frequency, wake times, time to fall asleep)
  • mood and anxiety
  • migraines or headaches
  • breast tenderness
  • libido and vaginal symptoms (dryness, sex drive)
  • joint pain or muscle aches
  • training tolerance
  • Stress load and tolerance

Useful blood tests to discuss with your GP may include iron studies, thyroid function, fasting glucose or HbA1c, lipids, vitamin D, B12 and other markers depending on your history. Hormones may be tested in some cases, but they are not always the first or most useful step.

This data is so useful for you to bring to a naturopathic consultation too. While we would generally ask questions like this during a consultation, this level of detail gives us much better insight as to what is going on, and allows us to support you better.

Also Consider Some Foundations

  • Eat more regularity and ensure your meals are protein rich
  • lift weights two to three times per week, or just increase movement in general
  • Incorporate an evening sleep ritual (limit screen, drink a tea and read a book)
  • Be kind to yourself and know that this process is a normal transition

The Takeaway

Perimenopause is a hormonal transition, but it is also a whole-body transition.

It can affect cycles, sleep, mood, cognition, libido, bleeding, muscle, bone, blood glucose, stress tolerance and body composition. The pattern can be messy because hormones fluctuate rather than decline in a straight line.

The best approach is not panic, guesswork or random supplements. It is pattern recognition, sensible testing, strong lifestyle foundations and individualised care.

If you want help making sense of your symptoms, nutrition, sleep, blood glucose, stress load or supplement options, Stephen can help you build a practical plan that fits your body, health history and stage of life.

FAQ

What are the first signs of perimenopause?

The first sign is often a change in your menstrual cycle. Periods may become shorter, longer, heavier, lighter, more painful or less predictable. Some women also notice sleep problems, anxiety, night sweats, breast tenderness, migraines or brain fog before their cycle changes dramatically.

Can perimenopause start before 45?

Yes, it can. However, if your periods become irregular or stop before 45, it is worth speaking with your GP. Early menopause and premature ovarian insufficiency need proper assessment.

Why do I feel anxious during perimenopause?

Hormone fluctuations can affect the brain and nervous system. Lower or less consistent progesterone, sleep disruption, stress load, blood glucose swings and life pressure can all contribute. Anxiety in perimenopause is common, but it should still be supported properly.

Do I need a blood test to diagnose perimenopause?

Not always. In the usual age range, perimenopause is generally assessed through symptoms, cycle changes and medical history. Blood tests can still be useful to rule out other causes of symptoms or to assess broader health markers. The better test is a DUTCH test.

Is heavy bleeding normal in perimenopause?

Heavier bleeding can happen in perimenopause, but it should not be ignored. See your GP if bleeding is very heavy, prolonged, occurs between periods, happens after sex or occurs after menopause.

Can nutrition help perimenopause symptoms?

Nutrition can help support energy, mood, blood glucose, muscle, sleep and long-term health. It may not remove every symptom, but adequate protein, fibre-rich carbohydrates, healthy fats and enough total food can make the transition easier for many women.

Should I take supplements for perimenopause?

It depends on your symptoms, health history, medications and goals. Magnesium, creatine, zinc, herbs and other supports may be useful in selected cases, but they should be chosen carefully rather than taken randomly. Book a naturopathic health consultation first and ensure your supplements or herbals are tailored to you.

Is MHT safe?

MHT can be appropriate and helpful for many symptomatic women, but suitability depends on individual risk factors and medical history. Speak with your GP or a menopause-aware doctor to discuss benefits, risks and options.

References

Australian Government Department of Health, Disability and Ageing. (2026). Delivering the first national menopause campaign for Australian women. https://www.health.gov.au/ministers/the-hon-mark-butler-mp/media/delivering-the-first-national-menopause-campaign-for-australian-women

Forbes, S. C., Candow, D. G., Krentz, J. R., Roberts, M. D., & Young, K. C. (2021). Creatine supplementation in women’s health: A lifespan perspective. Nutrients, 13(3), 877. https://pmc.ncbi.nlm.nih.gov/articles/PMC7998865/

Healthdirect. (n.d.). Perimenopause. https://www.healthdirect.gov.au/perimenopause

Hechtman, L. (2025). Supporting patients through perimenopause: EndoMAP Code 1501. Seminar handout. NutriPATH.

Menopause: Symptoms, Causes And Management | Jean Hailes. (2026). In Jean Hailes. https://www.jeanhailes.org.au/health-topics/menopause/

Magraith, K., & Jang, C. (2026). Demystifying menopausal hormone therapy prescribing. Australian Journal of General Practice, 55(4). https://www1.racgp.org.au/ajgp/2026/april/demystifying-menopausal-hormone-therapy-prescribin

Park, Y. M., Jankowski, C. M., Ozemek, C., Hildreth, K. L., Kohrt, W. M., & Moreau, K. L. (2020). Appendicular lean mass is lower in late compared with early perimenopausal women: Potential role of FSH. Journal of Applied Physiology, 128(5), 1373-1380. https://pubmed.ncbi.nlm.nih.gov/32298212/

Peacock, K., & Ketvertis, K. M. (2023). Menopause. In National Library of Medicine. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK507826/

Prior, J. C. (2006). Perimenopause lost: Reframing the end of menstruation. Journal of Reproductive and Infant Psychology, 24(4), 323-335. https://doi.org/10.1080/02646830600974071

Skilton, A. (2026). The menopausal transition: A four-phase framework for HPA/HPO axis support. Clinical webinar handout. Designs for Health.

Beyond Iron: Why This Mineral Matters for More Than Energy and Fatigue

Most people think about iron when they feel tired, and it’s more relevant for females, too, in this context.

Iron is essential for making haemoglobin, the protein in red blood cells that helps carry oxygen around the body. When iron is low, fatigue, weakness, breathlessness, dizziness and reduced exercise tolerance can be some of the first things people notice.

But iron is not just an energy/fatigue nutrient. It’s also involved in brain function, neurotransmitter production, dopamine signalling, thyroid hormone metabolism, mitochondrial energy production, immune function, muscle performance, sleep quality and restless legs syndrome. This is why low iron can sometimes show up as brain fog, poor concentration, low mood, feeling wired but exhausted, poor sleep, restless legs or anxiety-like symptoms.

That does not mean every tired, anxious or foggy person has low iron. Symptoms overlap with stress, poor sleep, thyroid issues, low B12, low vitamin D, under-eating, heavy training, chronic inflammation, alcohol history, gut issues, medications, pregnancy, postpartum depletion and many other causes, the list goes on.

In this article, we’ll unpack iron, including it’s simple role as a “fatigue” nutrient, and also beyond so that you can understand it further.

What To Know (Article Snapshot)

  • Iron helps carry oxygen through haemoglobin and supports oxygen use in muscles through myoglobin.
  • Iron is also involved in cellular energy production, thyroid hormone metabolism, neurotransmitter synthesis and brain development.
  • Low iron can exist before anaemia shows up on a standard full blood count.
  • Ferritin is commonly used to assess iron stores, but it needs to be interpreted in context because inflammation can raise ferritin.
  • Low iron may contribute to fatigue, reduced exercise tolerance, poor concentration, low mood, restless legs, poor sleep and anxiety-like symptoms in some people.
  • Restless legs syndrome has one of the stronger links with iron regulation, especially brain iron and dopamine pathways.
  • Iron supplements should not be taken casually without testing and guidance. Too much iron can be harmful.

Why Does Low Iron = Low Energy & Fatigue?

Iron is best known for transporting oxygen through-out the body.

Your body uses iron to make haemoglobin, which carries oxygen from the lungs through the bloodstream. Iron is also part of myoglobin, which helps muscles access and use oxygen. So, without iron, these two functions don’t operate per usual, leading to fatigue (NIH Office of Dietary Supplements).

So, all the talk on iron deficiency and fatigue is warranted, iron matters for energy.

But, that’s only the small part of the story.

Iron is also part of the enzymes and proteins that help generate cellular energy, regulate oxidative stress, and support normal neurological function,

When iron status is low, we present with symptoms related to fatigue. It may look like heavy limbs, brain fog, poor motivation, or reduced stress resilience.

Low Iron Is Not Always The Same As Anaemia

This is one of the most important points.

A person can have low iron stores without being anaemic.

Anaemia usually refers to low haemoglobin or a reduced ability of the blood to carry oxygen. Iron deficiency can eventually lead to iron deficiency anaemia, but iron stores may fall before haemoglobin drops below range.

This is where ferritin becomes useful. Ferritin is a protein that stores iron. Low ferritin often suggests depleted iron stores.

Australian Prescriber notes that non-anaemic iron deficiency is common, can cause non-specific symptoms, and is usually seen as low ferritin and low transferrin saturation with normal haemoglobin (Australian Prescriber).

That does not mean ferritin is the only marker that matters. Ferritin can rise with inflammation, infection, liver disease and other contexts, so a result that looks normal does not always tell the whole story.

This is why we generally want to look at the whole picture, and and also assess other factors including inflammatory markers, menstrual loss, diet, lifestyle, and more. (Auerbach et al., 2025)

When iron is low, we should be asking, why is it low and what else is happening around it?

Iron And The Brain

Iron is present throughout the brain and is involved in several processes that matter for cognition, mood, movement and nervous-system function.

A systematic review on women of childbearing age found evidence linking iron deficiency with poorer cognition, mental health scores and fatigue in several studies (Greig et al., 2013).

Although the authors noted more research is warranted, it does underscore the link on iron and brain function. It suggests that iron status can be relevant when someone presents with persistent fatigue, brain fog, low concentration, reduced motivation or mood changes.

If we look further, we can begin to see irons critical role in neurotransmitter synthesis and long-term nerve function.

Iron, Dopamine and Serotonin

Iron is a vital co-factor for enzymes involved in synthesising two key neurotransmitters, Dopamine and Serotonin.

These two fairly well known neurotransmitters are heavily involved in regulating our mood, motivation, focus, hunger and drive (to note a few).

In plain English, iron is part of the biochemical step to make these. When iron status insufficient, we see alterations in dopamine pathways, and impacts in emotional regulation and mood (Pivina et al., 2019).

Interestingly, we also need adequate iron for long-term nerve health. Iron is required for the production of myelin (the coating around our nerves). Some studies suggest early-life iron deficiency can impact this long-term, leading to deficits in neural development (Gao et al., 2025).

Iron And Restless Legs

Restless legs syndrome is one of the strongest reasons to think about iron beyond fatigue.

Restless legs can feel like an uncomfortable urge to move the legs, usually worse at rest or in the evening. It can make sleep difficult and leave someone exhausted during the day.

Iron regulation, brain iron and dopamine pathways are central to current discussions of restless legs syndrome. A 2025 review describes the link between iron deficiency and restless legs syndrome and explains how altered iron metabolism may contribute to the condition (Rizvi et al., 2025). A 2025 article in Sleep notes that iron dysregulation in the brain is now thought to play a fundamental role in the pathophysiology of restless legs syndrome (Sleep).

The American Academy of Sleep Medicine’s clinical practice guideline also recommends iron treatment in specific restless legs contexts where iron indices are appropriate, particularly intravenous ferric carboxymaltose for adults with restless legs syndrome and suitable iron status (AASM guideline summary on PubMed).

This does not mean everyone with restless legs should start iron. It means iron studies are often clinically relevant, especially when symptoms affect sleep.

For the average person, the useful takeaway is this: if you have restless legs, poor sleep and fatigue, it may be worth checking ferritin and full iron studies rather than assuming it is just stress, ageing or poor sleep hygiene.

Iron, Thyroid Function And Metabolism

Iron is also relevant to thyroid physiology.

Thyroid peroxidase, an enzyme involved in thyroid hormone synthesis, is iron-dependent. This is one reason iron deficiency has been studied in relation to thyroid function.

A 2023 systematic review and meta-analysis reported relationships between iron deficiency and thyroid function, including differences in TSH, free T4 and free T3 in some groups, particularly pregnant women and women of reproductive age (Garofalo et al., 2023). A 2021 systematic review and meta-analysis also examined iron deficiency as a risk factor for thyroid disorders in reproductive-age and pregnant women (Luo et al., 2021).

This means iron should be used as part of the bigger picture when someone is presenting with fatigue, cold sensitivity, low mood, hair loss. Thyroid function, iron status, inflammation, menstrual blood loss, protein intake, iodine, selenium, stress and sleep can all overlap.

Low Iron and Anxiety

Low iron can contribute to anxiety in a few overlapping ways.

The first is through oxygen delivery. When iron is low, the body may have a harder time making enough haemoglobin and moving oxygen efficiently. That can lead to symptoms such as racing heart, palpitations, shortness of breath, dizziness, poor exercise tolerance and feeling physically unsettled (Healthdirect Australia).

The second pathway is through the brain. Iron is involved in brain energy metabolism, myelination and monoamine neurotransmitter metabolism, including dopamine and serotonin pathways (Kim & Wessling-Resnick, 2014).

As mentioned previously, These neurotransmitters help regulate mood, motivation, focus, emotional steadiness and stress response. When iron availability is poor, these pathways may not function as smoothly, leading to anxiety.

One study in children with iron deficiency anaemia found changes in plasma dopamine, serotonin and brain-derived neurotrophic factor in response to variation in iron availability (Bani-Ahmad et al., 2022).

There is also emerging genetic evidence supporting a relationship between iron status and anxiety risk. A 2024 Mendelian randomisation study found that genetically predicted iron status biomarkers were linked with anxiety disorder risk (Yin et al., 2024).

Who Is More At Risk Of Low Iron?

Iron deficiency can happen because intake is low, needs are higher, absorption is reduced or losses are increased (if you were to look at it fundamentally).

Some common risk factors include:

  • Heavy menstrual bleedin
  • Pregnancy or postpartum recovery
  • Vegetarian or vegan diets without careful planning
  • Low overall food intake
  • Endurance training or high training loads (Foot-strike hemolysis)
  • Frequent blood donation
  • Gut conditions that affect absorption
  • Coeliac disease or inflammatory bowel disease
  • Long-term use of some medications that affect stomach acid or gut function
  • A history of iron deficiency
  • Diets low in iron-rich foods, protein or vitamin C

If iron is low because of heavy menstrual bleeding, gut bleeding, poor absorption or inflammation, simply taking a supplement without understanding the reason can leave the issue unresolved, and does not address the root cause.

Food Sources Of Iron

There are two main types of dietary iron: haem iron and non-haem iron.

Haem iron is found in animal foods and is generally more readily absorbed. Non-haem iron is found in plant foods and fortified foods. The NIH notes that haem iron has higher bioavailability than non-haem iron, and that vegetarian diets usually have lower iron bioavailability than mixed diets containing meat, seafood and vitamin C-rich foods (NIH Office of Dietary Supplements).

The numbers below are approximate iron amounts per 100g. They can vary depending on the cut, cooking method, brand, fortification level and database used (Healthdirect Australia; Nutrition Australia; USDA FoodData Central).

Haem iron foods

  • Beef: approximately 2.5-3.5mg per 100g
  • Lamb: approximately 2.5mg per 100g
  • Kangaroo: approximately 3.2-4.1mg per 100g
  • Chicken: approximately 0.4-1.3mg per 100g
  • Turkey: approximately 0.7-1.4mg per 100g, depending on white or dark meat
  • Fish: approximately 0.3-1.3mg per 100g, depending on the fish
  • Sardines: approximately 2.5-6.1mg per 100g, depending on whether canned or cooked/fried
  • Tuna: approximately 1.1-1.5mg per 100g
  • Oysters and mussels: approximately 6-9mg per 100g
  • Liver or organ meats, where appropriate: approximately 6-11mg per 100g, depending on the type

Non-haem iron foods

  • Lentils: approximately 3.3mg cooked or 9.1mg dry per 100g
  • Chickpeas: approximately 1.8-2.9mg per 100g
  • Beans: approximately 2-3mg per 100g, depending on the type
  • Tofu: approximately 2.9mg per 100g
  • Tempeh: approximately 2.7mg per 100g
  • Pumpkin seeds: approximately 8-9mg per 100g
  • Sesame seeds and tahini: sesame seeds approximately 14mg per 100g; tahini approximately 2-3mg per 100g
  • Cashews: approximately 5mg per 100g
  • Spinach and leafy greens: raw spinach approximately 3mg per 100g; cooked spinach can be higher per 100g because it is more concentrated
  • Quinoa: approximately 1.5mg cooked or 4.6mg dry per 100g
  • Iron-fortified cereals: varies widely, often approximately 8-16mg per serve depending on the product
  • Whole grains: approximately 1-4mg per 100g, depending on the grain
  • Dried apricots: approximately 3.1-6.3mg per 100g

Plant-based eaters can build iron-rich diets, but they usually need to be more intentional about absorption.

How To Improve Iron Absorption From Food

Iron absorption depends on the type of iron, the meal composition and the person’s current iron status.

Simple food-first strategies include:

  • Pair plant-based iron foods with vitamin C, such as citrus, kiwi, berries, capsicum or tomato.
  • Include haem iron foods if they fit your diet and values.
  • Avoid drinking tea or coffee directly with iron-rich meals if iron status is low.
  • Be mindful that calcium supplements can reduce iron absorption when taken at the same time.
  • Build meals around protein, colourful plants and enough overall food, not just one iron-rich ingredient.

Harvard’s Nutrition Source notes that vitamin C and haem iron can improve non-haem iron absorption, while phytates, tannins and large amounts of calcium can inhibit non-haem iron absorption (Harvard T.H. Chan School of Public Health).

Why You Should Not Self-Prescribe Iron

While supplementing with iron can be the most simple solution, consuming too much iron is equally as harmful as consuming too little.

Having too much iron in the body is toxic and can be fatal, and this is because it’s highly oxidative (think of too much oxidation as cellular rust).

Some people are also at risk of iron overload conditions such as haemochromatosis. This condition involves the inability to metabolise and clear iron from the body as fast as most people These people often need to give blood or reduce iron consumption, so if you have this condition, you definitely do not want to be touching an iron supplement.

Some iron supplements can also cause constipation, nausea, stomach pain and digestive discomfort. Usually, this depends on the type of supplement and iron source you choose, so it’s always good to discuss with a health practitioner first before supplementing with iron.

A sensible approach to take before taking an iron supplement includes:

  1. Test your iron levels first and understand your serum iron, ferritin and transferrin levels.
  2. Discuss with a health professional to understand the broader scope or other causative factors.
  3. Implement food first approaches alongside a good, bioavailable iron supplement.
  4. Recheck levels at a later date to measure against your first test baseline.
  5. Stop, reduce or adjust when appropriate.

When To Seek Professional Guidance

It is worth seeking guidance if you have ongoing symptoms such as:

  • Fatigue that does not improve with rest
  • Breathlessness on exertion
  • Dizziness or light-headedness
  • Poor concentration or memory issues
  • Restless legs or sleep disruption
  • Heavy menstrual bleeding
  • Hair shedding with fatigue or low mood
  • Reduced exercise tolerance
  • Pale skin or unusual weakness
  • A history of low ferritin or iron deficiency
  • Gut symptoms, blood in stool or unexplained weight changes

It is especially important to seek medical care if symptoms are severe, new, worsening or linked with possible blood loss or fainting.

Seeking out a Naturopath or Nutritionist can help interpret your blood results in context with other factors that could be causative factors to your low iron and overall fatigue picture.

The Takeaway

Iron is bigger than energy and fatigue.

It helps carry oxygen, but it also supports cellular energy production, brain function, dopamine-related pathways, sleep, restless legs, thyroid physiology and nervous-system resilience.

That is why low iron can sometimes feel like more than tiredness. It may show up as fogginess, poor concentration, low motivation, poor sleep, restless legs, reduced exercise tolerance or feeling wired but depleted.

But symptoms alone are not enough to diagnose low iron.

The smart approach is to test, interpret the results properly and understand why iron may be low in the first place. Food can help. Absorption strategies can help. Supplements may be useful when there is a confirmed need. But iron should not be taken casually without testing and guidance.

If you are dealing with fatigue, brain fog, restless legs, poor sleep, low mood, heavy periods or reduced exercise tolerance, Stephen can help you look at the bigger picture: diet, iron intake, ferritin and iron studies, nervous-system load, sleep, stress, training, thyroid context and other nutrients that may be part of the pattern.

FAQ

Why is iron more than an energy nutrient?

Iron helps carry oxygen, but it is also involved in cellular energy production, brain function, neurotransmitter synthesis, dopamine pathways, thyroid hormone metabolism, immune function and nervous-system health. That is why low iron can affect more than fatigue.

Can low iron cause anxiety-like symptoms?

Low iron can sometimes contribute to symptoms that overlap with anxiety, such as shortness of breath, racing heart, restlessness, poor sleep, dizziness, fatigue and reduced stress tolerance. It is not the only possible cause, so testing and proper assessment matter.

What is ferritin?

Ferritin is a protein that stores iron. Low ferritin can suggest low iron stores, even when haemoglobin is still normal. Ferritin can also rise with inflammation or illness, so it should be interpreted alongside symptoms, full blood count, iron studies and health context.

Can you have low iron without being anaemic?

Yes. Iron stores can become low before haemoglobin drops low enough to be classified as anaemia. This is often called non-anaemic iron deficiency. It may still be associated with symptoms such as fatigue, poor concentration, reduced exercise tolerance or restless legs.

Can low iron affect sleep?

Low iron can be linked with restless legs syndrome, which can disrupt sleep. Low iron may also contribute indirectly to fatigue, restlessness or poor recovery. Sleep problems can have many causes, so iron is one possible factor to investigate.

What foods contain iron?

Animal sources include beef, lamb, poultry, fish, seafood and organ meats. Plant sources include lentils, beans, chickpeas, tofu, tempeh, pumpkin seeds, tahini, leafy greens, quinoa and iron-fortified cereals. Pairing plant iron with vitamin C-rich foods can improve absorption.

Should I take iron supplements without testing?

No. Iron supplements should not be taken casually without testing or professional guidance. Too much iron can be harmful, and symptoms of low iron can overlap with many other issues. It is better to confirm whether iron is low, understand the cause and use the right approach.

Is plant-based iron enough?

It can be, but plant-based eaters usually need to be more intentional. Plant foods contain non-haem iron, which is less readily absorbed than haem iron and more affected by meal composition. Vitamin C-rich foods, adequate protein and smart meal timing can help.

How long does it take to improve low iron?

It depends on the severity, cause, treatment approach, absorption, diet and whether ongoing blood loss is present. Some people feel better within weeks, while iron stores may take longer to rebuild. Follow-up testing helps confirm whether the plan is working.

References

American Academy of Sleep Medicine. (2025). Treatment of restless legs syndrome and periodic limb movement disorder: An American Academy of Sleep Medicine clinical practice guideline. https://pubmed.ncbi.nlm.nih.gov/39324694/

Auerbach, M., DeLoughery, T. G., & Tirnauer, J. S. (2025). Iron deficiency in adults: A review. JAMA, 333(20), 1813-1823. https://doi.org/10.1001/jama.2025.0452

Australian Prescriber. (2021). Non-anaemic iron deficiency. https://australianprescriber.tg.org.au/articles/non-anaemic-iron-deficiency.html

Bani-Ahmad, M., Ahmad, M., Obeidat, M., & Barqawi, M. (2022). The modulation of plasma levels of dopamine, serotonin, and brain-derived neurotrophic factor in response to variation in iron availability. Acta Biomedica, 93(6), e2022293. https://doi.org/10.23750/abm.v93i6.13276

Gao, Q., Zhou, Y., Chen, Y., Hu, W., Jin, W., Zhou, C., Yuan, H., Li, J., Lin, Z., & Lin, W. (2025). Role of iron in brain development, aging, and neurodegenerative diseases. Annals of Medicine, 57(1), 2472871. https://doi.org/10.1080/07853890.2025.2472871

Garofalo, V., Condorelli, R. A., Cannarella, R., Aversa, A., Calogero, A. E., & La Vignera, S. (2023). Relationship between iron deficiency and thyroid function: A systematic review and meta-analysis. https://pubmed.ncbi.nlm.nih.gov/38004184/

Greig, A. J., Patterson, A. J., Collins, C. E., & Chalmers, K. A. (2013). Iron deficiency, cognition, mental health and fatigue in women of childbearing age: A systematic review. https://pubmed.ncbi.nlm.nih.gov/25191562/

Harvard T.H. Chan School of Public Health. Iron. https://nutritionsource.hsph.harvard.edu/iron/

Healthdirect Australia. How to meet your iron needs. https://www.healthdirect.gov.au/how-to-meet-your-iron-needs-infographic

Healthdirect Australia. Iron deficiency. https://www.healthdirect.gov.au/iron-deficiency

Kim, J., & Wessling-Resnick, M. (2014). Iron and mechanisms of emotional behavior. Journal of Nutritional Biochemistry, 25(11), 1101-1107. https://doi.org/10.1016/j.jnutbio.2014.07.003

Luo, J., Wang, X., Yuan, L., & Guo, L. (2021). Iron deficiency, a risk factor of thyroid disorders in reproductive-age and pregnant women: A systematic review and meta-analysis. https://pmc.ncbi.nlm.nih.gov/articles/PMC7947868/

National Institutes of Health, Office of Dietary Supplements. Iron: Fact Sheet for Health Professionals. https://ods.od.nih.gov/factsheets/Iron-HealthProfessional/

Nutrition Australia. (2021). Iron. https://nutritionaustralia.org/resources/iron/

Pivina, L., Semenova, Y., Doşa, M. D., Dauletyarova, M., & Bjørklund, G. (2019). Iron deficiency, cognitive functions, and neurobehavioral disorders in children. Journal of Molecular Neuroscience, 68(1), 1-10. https://doi.org/10.1007/s12031-019-01276-1

Rizvi, S., et al. (2025). Restless legs and iron deficiency: Unravelling the hidden link and current evidence. https://pmc.ncbi.nlm.nih.gov/articles/PMC12084866/

Sleep. (2025). Bringing iron to the brain for restless legs. https://academic.oup.com/sleep/article/48/7/zsaf128/8129076

U.S. Department of Agriculture. FoodData Central. https://fdc.nal.usda.gov/

Yin, R., Gao, Q., Fu, G., & Zhao, Q. (2024). The causal effect of iron status on risk of anxiety disorders: A two-sample Mendelian randomization study. PLOS ONE, 19(3), e0300143. https://doi.org/10.1371/journal.pone.0300143

Theme: Overlay by Kaira.