• GABA is your brain’s main calming messenger. It turns down nervous system activity so you can let things go and sleep.
• Progesterone breaks down into a compound that makes GABA work better. As progesterone becomes erratic, that support comes and goes.
• Oestrogen helps to switch off your stress response. As it falls, cortisol can stay raised for longer.
• This kind of anxiety often has no cause you can name, and it often feels physical rather than mental.
• Hormonal change is a reasonable working assumption after 40, and it is not the only thing that produces this experience.
• HRT helps some women a great deal and others very little, and it does not recreate the pattern your body used to run on.
• Stable blood sugar, better sleep and less cumulative load all give your nervous system more to work with.
• Magnesium, vitamin B6, omega-3 fats and protein are the nutrients your calming system depends on most.
• Ashwagandha, lemon balm, passionflower and chamomile all have trial evidence behind them, and all work at the level of the nervous system.

For many women, the first sign that something hormonal is changing is not a hot flush. It is a change in how you feel inside.

Your heart races on waking. There is a hum of tension that was not there in your thirties. You feel on edge without being able to point to why. Sleep is broken, and things you used to take in your stride feel harder to manage.

First anxiety after 40 is common. In a study that followed nearly 3,000 women for ten years, those with little anxiety to begin with were around one and a half times more likely to report high anxiety  once they reached perimenopause. That held true even after the researchers accounted for stressful life events, money worries and hot flushes.

What you are noticing is your nervous system responding to hormonal change. Once you understand the mechanism, the things that help start to make sense.

Irritability is part of it too, and you feel it even before you have had time to think. So is the feeling of being wired and worn out at once, which women often describe as the strangest part of it.

When GABA is working well, you can let things go. You can fall asleep. You can feel the edge of stress without being overwhelmed by it. It is the brake, not the accelerator.

Progesterone breaks down into a compound called allopregnanolone. It acts directly on the receptors that GABA uses, making GABA more effective.

Researchers reviewing how the GABA system responds to hormonal change describe exactly this. Allopregnanolone rises and falls with progesterone, and the calming effect rises and falls with it.

In perimenopause, progesterone becomes unpredictable long before it disappears. Some cycles produce plenty, others produce very little. Your supply of allopregnanolone follows the same pattern, so the calming support you have relied on for thirty years becomes intermittent. That is often felt as a background unease, or a sense of running closer to the edge than you used to.

Tracking what you feel against the dates of your period for two or three months is worth doing. It tells you whether there is a pattern to work with, and it gives you something concrete to bring to a consultation.

As oestrogen falls and fluctuates, that feedback becomes less reliable. Cortisol can stay raised for longer, and your nervous system takes more time to return to where it started.

This is why the same stressor that felt manageable at 35 can feel much heavier at 45. You have not become less capable. The biological buffer you had is thinner.

An anxiety disorder is a clinical diagnosis with its own pattern and its own history. What emerges in perimenopause is driven by hormonal change, and it behaves differently.

There is usually no psychological trigger behind it. It often feels physical rather than mental: your heart pounding, your chest tight, a jolt of alertness at three in the morning for no reason you can find.

Talking approaches can help, and I would never steer a woman away from them. But if the cause is hormonal, that is where the work needs to go.

Hormonal change explains a great deal of new anxiety after 40, and it is a reasonable working assumption for most women over 40. It is not the only thing that produces this experience.

An overactive thyroid causes a pounding heart, tremor, heat and a feeling of anxiety, and it becomes more common with age. Low iron and low B12 both produce breathlessness, palpitations and unease. Blood sugar that drops sharply after a meal can leave you shaky and panicky an hour or two after eating. Each of these has its own pattern, and any of them can occur alongside hormonal change rather than instead of it.

Thyroid function, a full blood count, ferritin and B12 are straightforward tests, and they rule some of these causes in or out. A result on its own says less than it appears to, so it is interpreted alongside everything else you are experiencing. That is what narrows the picture down, even when it does not produce a single clear answer.

Some women reading this will already be taking HRT. Others will be weighing it up, or will have been told it is not an option for them.

It is a fair question to ask here, because the mechanism points straight at it. If falling oestrogen and erratic progesterone are behind what you are feeling, replacing them sounds like the obvious answer.

Sometimes it is. Body identical progesterone breaks down into allopregnanolone, the same compound described above, so it acts on the calming system in the same way. Pooling four trials, women taking it fell asleep around seven minutes faster, although total sleep time did not change.

Oestrogen has its own evidence in this area. In a placebo controlled trial, perimenopausal women given oestradiol patches for eight weeks reported less anxiety than those given placebo. What stands out in that trial is who improved most: the women whose mood already moved with their own oestrogen levels. The response was far from uniform.

HRT helps some women a great deal, helps others a little, and does little for a few. A fixed daily dose does not recreate the pattern your body used to run on, and it does not undo the load your nervous system is carrying.

Some women are advised against it for medical reasons. Others try it and find it is not for them. A few simply do not want it.

HRT is one part of the picture rather than the whole of it. The food you eat, the sleep you get and the support you give your nervous system all still matter, whether you take it or not. If you are taking herbs alongside HRT, check that combination with a herbalist who can see your full prescription.

Blood sugar

Sharp rises and falls in blood sugar trigger a cortisol response. Meals built around protein, fat and fibre keep those swings smaller. Caffeine is worth a thought too, because in a nervous system with less hormonal buffering it keeps cortisol raised for longer.

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Sleep

Cortisol rises naturally in the early morning. If your sleep is broken, that rise lands on a nervous system that has not recovered. Anxiety and poor sleep feed each other, so improving one usually improves the other.

Cumulative load

Your nervous system has less buffer than it did, so reducing what it has to absorb makes a direct difference. Alcohol is the one most women underestimate. It feels calming in the evening and then fragments sleep and raises cortisol in the small hours.

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Magnesium

It is involved in hundreds of reactions in the body, including several in the nervous system. Reviewing seven trials that measured anxiety, five reported an improvement, although the studies were small and varied. Green leafy vegetables, nuts, seeds, beans and dark chocolate all contain it.

Vitamin B6

Your body needs it to make GABA in the first place, because the enzyme that converts glutamate into GABA cannot work without it. Fish, poultry, chickpeas, bananas and potatoes are all good sources.

Omega-3 fats

A 2024 pooled analysis of 23 trials found omega-3 supplements lowered anxiety scores, with the greatest improvement at around two grams a day. Below that dose, the trials found no effect. The strongest trials in that analysis showed less of an effect than the weaker ones, so the size of the benefit is uncertain. Oily fish twice a week is where I would start.

Protein

It keeps blood sugar changes smaller across the day, and it supplies the amino acids your brain uses to make its messengers. Twenty to thirty grams at breakfast does more for the rest of the day than any other single change I suggest.

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The bacteria in your gut make GABA. Lactobacillus, Bifidobacterium and Bacteroides species all carry the enzyme that produces it, and they talk to your brain along the vagus nerve. Much of this work is early, and most of it is in animals rather than women, so I would not want to promise you more than the evidence gives.

What I would say is that the things that support your gut health are the same things that support your nervous system. Fibre from a wide range of plants, fermented foods, and enough time between meals for digestion to do its work. Many women notice their digestion changing at the same time as their mood, and the two are connected more closely than most people expect.

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Ashwagandha (Withania somnifera)

This works on the stress response rather than sedating you. A 2025 review of 15 trials found it lowered cortisol, perceived stress and anxiety scores. A separate 2025 review found cortisol fell while perceived stress scores did not move, which is what tends to happen when a subjective score is averaged across very different people. In my experience, I find it a reliable herb, and it does its best work where the picture is one of long running pressure rather than acute panic.

Lemon balm (Melissa officinalis)

Works on GABA itself. Laboratory work shows its compounds slow the enzyme that breaks GABA down, which leaves more of it available to act. A small open trial reported less anxiety and better sleep although it had no placebo group, so it can only point in a direction. It is gentle enough for everyday use, which is part of why I like it.

Passionflower (Passiflora incarnata)

This is my choice where the anxiety is acute rather than constant, and where it interferes with getting to sleep. Across nine trials, most reported lower anxiety scores, and the effect was clearer in people whose anxiety was more than mild.

Chamomile (Matricaria chamomilla)

Chamomile is far more than a bedtime tea. Its flavonoid apigenin binds to the same GABA receptors described above. In a trial where people who had improved on chamomile either stayed on it or were moved to placebo, fewer of those who stayed on it relapsed, although that difference was not statistically strong.

Which of these four suits you depends on the whole picture, not on the anxiety alone. Long running pressure with exhaustion behind it points one way. Broken sleep and a racing heart at night point another. That matching is the part a trial cannot do.

The real caution with all of them is if you take medication, particularly for your thyroid or your mood, and that is worth checking with a herbalist who knows your case.

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For many women it eases. Tracking women through the whole transition, researchers found the odds of high anxiety peaked in late perimenopause. After menopause they came down again, though not all the way back to where they started. Once oestrogen and progesterone are low but no longer erratic, your nervous system has something predictable to work with again.

That can be several years, which is not much comfort at three in the morning. It is a reason to support your nervous system now rather than wait it out.

Anxiety that turns up in your forties for the first time is not a sign that you have become a more anxious person. It is a nervous system that has lost some of the hormonal support it used to take for granted.

That support can be rebuilt from more than one direction. What you eat, how you sleep, how much you are carrying, and the right herbs alongside those.

If this sounds like you, and you would like some support, please get in touch.