Brain fog, anxiety, mood swings: could these be symptoms of perimenopause?

Much is said about the menopause — that precise moment when periods have stopped permanently for 12 consecutive months. But far less is said about what happens in the lead-up: perimenopause!

This transition phase most commonly begins after the age of 40 and lasts several years (on average 4 to 8 years). It is a period during which your hormones, oestrogen and progesterone in particular, begin to fluctuate in an irregular and progressive way before declining permanently.

What is often misunderstood is that the first symptoms of perimenopause are not always physical. For many women, it is the neurological and emotional symptoms that appear first, and these are also the most unsettling. Some studies suggest that up to 80% of women experience neuropsychological symptoms during the menopausal transition [1]. Yet how many of them are offered an antidepressant, or led to believe it is simply down to stress, without the hormonal angle ever being explored.

Here are the most common — and sometimes most poorly identified — manifestations of perimenopause.

• Brain fog (brain fog): you walk into a room and can't remember why. You search for your words mid-conversation. You read the same sentence three times without it sinking in. This is not a sign of premature ageing, nor the beginning of dementia. It is a direct consequence of hormonal fluctuations on your brain.
• Sudden anxiety: it can arise without any trigger, sometimes even in the form of nocturnal panic attacks. Women who had never experienced anxiety in their lives suddenly find themselves with a constant sense of tension and difficulty "letting go". They seek help, and are prescribed anxiolytics — sometimes without perimenopause ever being mentioned.
• Mood swings and anger: some women describe the sudden onset of an irritability they don't recognise in themselves, with an intolerance towards situations that previously didn't affect them. Sometimes it's an intense, hard-to-contain rage. These changes are real, scientifically documented, and experienced by around 70% of women going through the menopausal transition, according to some studies [2].
• Cognitive fatigue: perimenopause doesn't only cause physical fatigue. Cognitive fatigue is that feeling that your brain is running in slow motion, that every decision requires a colossal effort, that the mental load has become almost unbearable.

If you recognise yourself in one or more of these symptoms, please take them seriously. They are very likely signs of perimenopause that deserve particular attention.

To understand why all of this happens, we need to look more closely at the role your hormones play on your brain — in particular progesterone, oestrogen and cortisol.

Progesterone: your "calming" hormone

This is often the first hormone to decline during perimenopause, and also the one that tends to receive the least attention. Progesterone has a naturally calming effect on the nervous system: it binds to the brain's GABA receptors — the same ones targeted by certain anxiolytics — and promotes a state of calm and deep sleep.

When progesterone drops, this buffering effect disappears. The nervous system becomes more reactive and more vulnerable to stress. Sleep becomes fragmented and anxiety rises — you wake up at 3 in the morning for no apparent reason. It's not just in your head: it's neurochemistry!

Oestrogen: the conductor of neurotransmitters

You have oestrogen receptors throughout your body, including in key areas of the brain: the hippocampus (memory), the prefrontal cortex (decision-making, concentration), the amygdala (emotions) and the hypothalamus (temperature, stress). When oestrogen fluctuates, this entire cerebral ecosystem is disrupted [1].

Concretely, the decline in oestradiol (the most active form of oestrogen) leads to:

• A decline in serotonin — the feel-good hormone — which also regulates sleep and appetite. Its reduction is directly linked to depressive states and anxiety [3].
• A disruption to dopamine, associated with motivation, concentration and the sense of pleasure. Less dopamine means less drive, less focus, and sometimes even a form of apathy [4].
• Fluctuations in glutamate, a neurotransmitter essential for brain energy and mood regulation [5].

Cortisol: the anxiety/insomnia vicious cycle

Several studies suggest a tendency towards higher cortisol levels in some women during the menopausal transition, linked to hormonal fluctuations and sleep disturbances. When oestrogen declines, cortisol tends to rise [6]. And progesterone, which usually plays a regulatory role, is no longer present to compensate.

The result is a true vicious cycle: stress rises, sleep deteriorates, recovery is insufficient and tolerance to stress diminishes rapidly. What you are feeling is not a character weakness — it is a cascading physiological response.

What takes place during perimenopause is therefore a genuine neurological reorganisation. Your brain is adapting to a new hormonal environment. It is uncomfortable, sometimes very difficult to live with, but it is temporary and, above all, it can be supported with the right care.

Good news: there are practical solutions to help you navigate this period more serenely. Here are the levers that can make a real difference!

• Prioritise your sleep: sleep is the foundation of all nervous system and hormonal balance. When your nights are disrupted, everything else suffers. A few simple habits can help improve sleep quality: getting exposure to natural light in the morning, limiting screens in the two hours before bed, or avoiding alcohol in the evening (which fragments sleep, even in small amounts).
• Move regularly: physical activity is one of the best-evidenced approaches against anxiety and mild depression during perimenopause. It naturally stimulates serotonin and dopamine, improves sleep quality and reduces cortisol. There's no need to immediately take up marathon running: walking, swimming, yoga or Pilates all have measurable effects [7].
• Adopt an anti-inflammatory diet: oestrogens play a key role in regulating inflammation. Their decline can promote an inflammatory environment, which in turn may worsen depressive and cognitive symptoms. Studies show that a diet rich in omega-3s, fibre and antioxidants helps to reduce this risk [8].
• Practise stress management techniques: heart rate coherence, mindfulness meditation, journalling — these approaches have demonstrated their effectiveness in reducing anxiety symptoms in women going through perimenopause [9]. They are not just "wellness gimmicks" — they are effective neurobiological tools!
• Meet your specific nutritional needs: diet alone can have its limits. During perimenopause, the need for certain micronutrients — particularly B vitamins and nutrients that support mental clarity — increases at the very time when digestion and absorption may be less efficient. This is where targeted supplementation can make a real difference.

To meet the specific needs of this life stage, Jolly Mama has formulated Péri Essentials: a multivitamin designed for women in perimenopause.

It combines 17 essential nutrients, including B vitamins (B1, B2, B3, B5, B6, B9, B12) which contribute to reducing fatigue, supporting the nervous system and regulating hormonal activity, as well as Bacopa Bacognize®, a patented active ingredient whose scientific research demonstrates beneficial effects on memory, concentration and emotional balance [10].

The formula is 100% vegan, made in France, with a daily dose of 2 capsules. Péri Essentials can be combined with Mama-gnésium (stress and sleep) and Oméga Mama (normal brain function) for even more comprehensive support.  

If you experience other symptoms such as hot flushes, you can combine it with Péri Support, based on sage, shatavari, saffron and milk thistle to support the body through these changes.