Why Anxiety in Perimenopause Is So Common — And What Your Body Is Actually Telling You

Anxiety is often one of the earliest symptoms of perimenopause — frequently appearing before cycle changes or hot flushes.

A client said something to me this week that I have heard, in one form or another, more times than I can count: “I don’t understand what’s happened to me. I’ve never been an anxious person. And now I lie awake at 3am with my heart racing, worrying about things that never used to touch me.” She is in her mid-forties. Her GP offered her antidepressants. Her blood tests were 'all normal'. And nobody, at any point, mentioned her hormones.

If this sounds familiar, I want you to know two things before you read any further. First: you are not imagining it, you are not losing it, and this is not a personality change. Second: anxiety in perimenopause has clear, well-documented biological mechanisms; and when you understand them, both the anxiety itself and the path through it start to make a great deal more sense.

As a Functional Medicine Practitioner working predominantly with women, anxiety is now one of the most common reasons women in their forties come to see me. Often it arrives before the symptoms they expect from perimenopause, before the hot flushes, before the cycle changes become obvious. Which is precisely why it so often goes unrecognised for what it is.

Cortisol, the HPA Axis and Why Stress Hits Differently Now

Estrogen and progesterone directly influence GABA, serotonin and the stress response — which is why hormonal change so often shows up first as anxiety.

There is a third player in this story, and it is the one that determines, more than any other, how turbulent a woman’s perimenopause will be: the stress response system, known as the HPA axis (hypothalamic-pituitary-adrenal axis).

Here is what is rarely explained to women. The ovaries and the adrenal glands are in constant conversation. As ovarian hormone production becomes erratic, the adrenal glands and the wider stress-response system are asked to pick up more of the load. If a woman arrives at perimenopause with a well-regulated stress response, the transition tends to be smoother. If she arrives, as so many women in their forties do, after years of chronic stress, poor sleep, caring responsibilities, demanding work and running on empty, the system has very little reserve left to give.

The result is a nervous system stuck closer to alert than rest: cortisol spiking at the wrong times, the classic 3am waking with a racing mind, an exaggerated startle response, and anxiety that seems wildly out of proportion to what is actually happening in your life.

This is also where the picture becomes genuinely individual. Blood sugar instability drives cortisol spikes that mimic and amplify anxiety: the mid-afternoon shakiness, the irritability before meals, the wired-but-tired evenings. Thyroid function, which commonly shifts at midlife, can produce anxiety, palpitations and restlessness of its own. Gut health influences both neurotransmitter production and inflammation, and the gut-brain axis is now one of the best-documented pathways in the whole of this field. And the very nutrients the nervous system depends on most — magnesium, B vitamins, vitamin C — are precisely the ones chronic stress depletes fastest.

In other words: perimenopausal anxiety is rarely one thing. It is an interaction between hormonal change and the terrain it lands on. Which is exactly why two women of the same age with the same symptom can need entirely different support.

Why 'Your Bloods Are Normal' Doesn’t Mean Nothing Is Wrong

One of the most demoralising experiences I hear about in clinic is the woman who finally seeks help, has blood tests, and is told everything is normal.

There are several reasons this happens. Hormone levels in perimenopause fluctuate so much that a single blood test is a snapshot of a moving target; a normal reading on Tuesday tells you very little about what your hormones were doing during last week’s anxiety spike. Standard reference ranges are designed to detect disease, not dysfunction, there is a wide territory between 'optimal' and 'diagnosable' in which a great deal of suffering takes place. And crucially, the standard panel rarely looks at the full picture: cortisol rhythm across the day, thyroid function beyond TSH, nutrient status, blood sugar regulation, gut health. 'Normal' results do not mean your experience isn’t real. They usually mean the right questions haven’t been asked yet.

A Functional Medicine Approach to Anxiety in Perimenopause

This is where a functional approach differs fundamentally from symptom management. Rather than asking “how do we suppress this anxiety?”, the functional question is: “what, in this individual woman, is driving it?” Is this primarily a progesterone-GABA picture? An HPA axis that has been running on fumes for a decade? Blood sugar chaos masquerading as panic? A thyroid quietly shifting? Nutrient depletion after years of stress, restrictive eating or long-term medication use? A gut that is inflaming the conversation between body and brain? Almost always, it is a combination — and the combination is different in every woman.

In my practice, that means a detailed clinical assessment: your full health history, your symptom patterns and their timing, your stress load, your diet, your medications, and where appropriate, functional testing that looks at the systems standard panels don’t: cortisol rhythm, comprehensive hormone metabolism, full thyroid function, nutrient status and gut health.

Only then does a plan make sense. And the plan is never generic. It draws on targeted nutritional support for the nervous system, herbal medicine; an area where, as a herbalist, I have powerful and time-tested tools and formulas specifically suited to this transition, blood sugar and cortisol regulation, gut work where it is needed, and genuine nervous system support that goes beyond being told to 'do some yoga.

I am deliberately not giving you a protocol here, and that is not because I am withholding the good bits. It is because there isn’t one. The entire reason perimenopausal anxiety is so poorly served by generic advice is that it is not a generic problem. The mechanisms are universal; the expression of them in your body is not.

You Are Not Anxious; You Are in Transition, Unsupported

If there is one message I want you to take from this article, it is this: anxiety in perimenopause is not a flaw in your character, a failure of resilience or simply 'your age'. It is a physiological signal from a body navigating one of the most significant hormonal transitions of your life — often while carrying the heaviest load of responsibilities you will ever carry.

Signals can be understood. Mechanisms can be addressed. And with the right assessment and the right support, this phase of life does not have to be endured with white knuckles. I see women move from 3am dread to genuine steadiness regularly — not because we silenced the signal, but because we listened to it properly. If you recognise yourself in this article and would like to explore what is driving your symptoms, I would be glad to help. You can book a free discovery call through the link here.

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Frequently Asked Questions

Why has my anxiety suddenly got worse in my forties when I've never been an anxious person before?

This is one of the most common things I hear in clinic, and the answer is almost always hormonal. Perimenopause — the transitional phase before periods stop — can begin in the early-to-mid forties, often before the symptoms women expect (hot flushes, cycle changes) appear. Oestrogen and progesterone directly influence the brain's calming neurotransmitters, particularly GABA and serotonin. As these hormones begin to fluctuate, the nervous system becomes less buffered — and anxiety that feels completely out of character is frequently the first sign that this transition has begun.

Could my anxiety be perimenopause if my periods are still regular?

Yes. Cycle regularity is one of the last things to change. Hormone levels — particularly progesterone — can begin to decline and fluctuate years before periods become irregular. Many women experiencing significant perimenopausal symptoms, including anxiety, sleep disruption and mood changes, still have what appears to be a normal cycle on the surface.

My GP did blood tests and said everything was normal. Does that mean my hormones aren't the problem?

Not necessarily. Hormone levels during perimenopause fluctuate considerably — a single blood test is a snapshot of a moving target, and a normal reading on one day tells you very little about what your hormones were doing during your worst symptoms. Standard reference ranges are also designed to detect disease, not dysfunction. There is a significant territory between "optimal" and "diagnosable" where a great deal of suffering takes place. If you have been told your bloods are normal but you are not well, the right questions may not yet have been asked.

What is the HPA axis and why does it matter in perimenopause?

The HPA axis is your stress response system — the chain of communication between the brain and the adrenal glands that governs cortisol and your fight-or-flight response. During perimenopause, as the ovaries become less reliable, the adrenal glands are asked to pick up more of the hormonal load. If you arrive at this transition after years of chronic stress, disrupted sleep or running on empty, the system has limited reserves left — which is why so many women find that stress hits harder, sleep deteriorates, and anxiety feels wildly out of proportion. It is not a character flaw; it is a depleted system being asked to do more.

Could blood sugar, thyroid or gut health be contributing to my anxiety?

Absolutely. Perimenopausal anxiety is rarely driven by hormones alone. Blood sugar instability produces cortisol spikes that closely mimic and amplify anxiety — the mid-afternoon shakiness, wired-but-tired evenings, and irritability before meals are all signs worth taking seriously. Thyroid function shifts commonly at midlife and can produce anxiety, palpitations and restlessness. The gut directly influences both neurotransmitter production and inflammation, and the gut-brain axis is now one of the most well-documented pathways in this field. A thorough assessment looks at all of these — not hormones in isolation.

Is there a supplement or protocol I can follow for perimenopausal anxiety?

This is precisely the question I am cautious about answering generically — and deliberately so. The mechanisms behind perimenopausal anxiety are universal, but how they express in any individual woman are not. What is driving anxiety for one woman (a progesterone-GABA picture, for instance) is entirely different from what is driving it for another (HPA dysregulation, or blood sugar chaos, or thyroid changes). A protocol designed for one may do very little — or the wrong thing — for another. The goal of a functional assessment is to understand your specific picture first, so that the support that follows is targeted rather than generic.

What does working with you actually involve?

It begins with a detailed clinical assessment: your full health history, symptom patterns and their timing, stress load, diet, medications and lifestyle. Where appropriate, this is supported by functional testing that looks beyond standard panels — cortisol rhythm across the day, comprehensive hormone metabolism, full thyroid function, nutrient status and gut health. From there, a plan is built around your specific drivers. This may include targeted nutritional support, herbal medicine (an area with powerful, time-tested tools for this transition), blood sugar and cortisol regulation, and genuine nervous system support. If you'd like to explore whether this approach is right for you, a free discovery call is the best place to start.

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Juliana O’Boyle IFMCP, MSc, AMH, ANP is a Functional Medicine Practitioner, Herbalist, Naturopath and Nutritionist with over 15 years of clinical experience. Through her Functional Herbalism approach, she combines the science of functional medicine with the wisdom of herbal medicine to help women uncover the root causes of digestive, hormonal and energy-related symptoms. Juliana holds an MSc in Personalised Nutrition, is certified through the Institute for Functional Medicine (IFM), and works with clients across the UK through her West London-based practice, Functional Herbology.