Why You Feel Anxious For No Reason
It's not your life. It's not your mindset. There's a specific neurochemical reason this is happening - and it starts with oestrogen.
By Jennifer Swallow, Nutrition Consultant
You're in the car on a Tuesday morning, driving a route you've driven a hundred times, and a wave of dread hits. Nothing has happened. There's no particular reason for it. Everything is, objectively, fine. But your nervous system hasn't got the memo, and the feeling sits in your chest for the rest of the day while you try to work out what you're actually worried about.
If you're in your forties and this has started happening - whether it shows up as free-floating anxiety, a lower threshold for feeling overwhelmed, a tendency to catastrophise things you'd have shrugged off before, or just a general unease that didn't used to be there - it almost certainly isn't your life circumstances. It's your hormones, and specifically it's what happens to the brain when oestrogen starts behaving the way it does in perimenopause.
What oestrogen does to your anxiety threshold
Most people know oestrogen as a reproductive hormone. What's less well known is that it plays a significant role in regulating two of the brain's most important mood-stabilising systems: GABA and serotonin. GABA is the brain's primary calming neurotransmitter - the signal that tells your nervous system to stand down. Oestrogen enhances how effectively GABA works, so when oestrogen fluctuates, GABA signalling becomes less reliable and the brain's ability to self-soothe after a perceived threat reduces accordingly.
Oestrogen also supports serotonin production and makes serotonin receptors more sensitive. Less oestrogen support means lower serotonin tone, which directly affects mood, resilience and how quickly anxiety takes hold. Progesterone matters here too. In perimenopause, progesterone tends to drop earlier and more steeply than oestrogen. A metabolite of progesterone called allopregnanolone is one of the most potent natural activators of GABA receptors in the brain, so as progesterone falls, another layer of the brain's natural calming capacity goes with it. This is why many women in perimenopause describe feeling like they've lost the ability to shake things off - because neurochemically, they have (temporarily, at least).
The amygdala - the brain's threat-detection centre - is also modulated by oestrogen. Without that modulation, it becomes more reactive: firing more readily, taking longer to settle, and generating anxiety in response to things that wouldn't have registered before.
Where nutrition makes a real difference
One thing that amplifies all of this significantly is blood sugar instability, and this is an area where nutrition makes an immediate, noticeable difference. When blood sugar drops, the body releases cortisol and adrenaline to compensate. For most people this feels like a sudden mood dip or irritability. In a brain that's already running with reduced GABA and serotonin support, that cortisol spike lands much harder. The anxiety that hits at 11am or late afternoon - the witching hours of poor eating patterns - is very often blood sugar, not psychology. The solution is the same as for brain fog: protein with every meal, fats and fibre alongside any carbohydrates, not going too long without eating.
Beyond blood sugar, magnesium is worth looking at closely. It's involved in GABA signalling and in regulating the stress response, and most women don't get enough of it from food alone. Magnesium glycinate - the form that's both well absorbed and calming rather than stimulating - is one of the most consistently useful interventions I see in practice for anxiety symptoms in perimenopause.
Vitamin B6 is a cofactor in the production of both serotonin and GABA, and deficiency is more common than people realise, particularly in women who are or have been on hormonal contraception. Poultry, fish, bananas, chickpeas and potatoes are reasonable dietary sources; if intake seems low, a B-complex supplement is worth considering alongside dietary changes.
Caffeine is also worth examining honestly. Oestrogen can affect how caffeine is metabolised, and in perimenopause many women find their tolerance for it has changed - the coffee that was fine at 2pm a few years ago is now keeping them wired at midnight and contributing to anxiety by the following morning. If anxiety is a feature, moving caffeine intake earlier in the day is one of the simplest practical changes to try first.
I spent a long time attributing a particular kind of low-level anxiety to my life circumstances before I understood what was actually happening. That understanding doesn't make the anxiety disappear overnight, but it does change the relationship you have with it - and it points you toward interventions that address the underlying cause rather than just managing the symptoms.
These aren't character flaws or signs that you're not coping. They're neurochemical changes with nutritional levers, and that makes them addressable. A Brain Fog Clarity Session covers mood and anxiety alongside cognitive symptoms - because in perimenopause, they almost always share the same root.