Brain fog in Perimenopause
Understanding what’s really going on, and what can help
if you have ever walked into a room and forgotten why you went there, lost your train of thought mid-conversation, or found it harder to focus, you may be experiencing what many women call brain fog.
During perimenopause, it can feel as though your thoughts are slower, your memory less reliable, and your concentration harder to hold. These changes can be unsettling, especially if you are used to juggling a busy job or family life with ease.
The good news is that brain fog is not a sign of cognitive decline. It is your brain adapting to hormonal and metabolic changes. Once you understand what is happening and how to support your body, mental clarity often returns naturally.
How hormones influence your brain
Oestrogen and progesterone do much more than regulate the menstrual cycle. They have a profound effect on how your brain functions.
Oestrogen supports blood flow, energy production and the creation of important brain chemicals called neurotransmitters, such as serotonin, dopamine and acetylcholine. These control mood, focus and memory.
In the early stages of perimenopause, oestrogen levels do not simply fall. They rise and drop unpredictably. When oestrogen is high, you may feel overstimulated or anxious. When it drops suddenly, energy and concentration can fall too.
In later perimenopause, oestrogen settles at a lower level. This can affect how well brain cells communicate and how efficiently they use glucose for energy. The result may be slower thinking, forgetfulness and lower motivation.
Progesterone also matters. It supports the calming neurotransmitter called GABA, which helps the brain to relax and sleep soundly. When progesterone falls, GABA levels do too. This can lead to lighter sleep, restlessness, anxiety and that “wired but tired” feeling that so many women describe.
These hormonal changes influence how you think, sleep, and respond to stress. They are temporary but can be frustrating while they are happening.
Why stress and overload make it worse
Perimenopause often arrives during a very demanding time of life. Between work, family, caring for others and constant multitasking, many women live in a state of low-level stress.
Chronic stress raises levels of cortisol, the body’s main stress hormone. High cortisol reduces blood flow to the part of the brain responsible for focus and memory and it interferes with sleep. It also depletes magnesium, zinc and B vitamins, nutrients that keep your nervous system healthy.
When stress and falling hormones combine, the result is often forgetfulness, scattered thinking and emotional fatigue. The brain is not failing; it is simply overloaded and under-fuelled.
The link between eating protein and brain clarity
What you eat has a direct effect on how well your brain works. A diet rich in protein provides amino acids, the building blocks of neurotransmitters that regulate mood, motivation and concentration.
Each amino acid plays a specific role:
Tyrosine, found in fish, tofu, beans, oats and seeds, helps your body make dopamine and noradrenaline, which support alertness and drive.
Tryptophan, found in oats, quinoa, pumpkin seeds and turkey, is used to create serotonin, which promotes calm, stable mood and restful sleep.
Glycine, glutamine and taurine help to calm the nervous system and support the GABA pathway that allows the mind to switch off at night.
Methionine and cysteine help with antioxidant protection and detoxification, which reduce inflammation that can dull mental focus.
During perimenopause, oestrogen fluctuations can affect how well your body uses these amino acids. This means you may need more variety and slightly higher protein intake than before. A good guide is around 1.2 to 1.5 grams of protein per kilogram of body weight per day, or about 70 to 100 grams for most women. Include a portion of protein at each meal from a mix of plant and fish sources such as lentils, tofu, quinoa, seeds and oily fish.
Why you shouldn’t skip out on carbohydrates
In recent years, many people have cut out carbohydrates in the name of better energy or weight control, but for women in perimenopause this can backfire.
Carbohydrates are your brain’s preferred fuel. The brain needs a steady supply of glucose to produce energy and maintain focus. When you restrict carbohydrates too much, blood sugar levels drop and the brain becomes under-fuelled. This can lead to fatigue, irritability and poor concentration.
Carbohydrates also play a role in serotonin production. The amino acid tryptophan needs carbohydrate to enter the brain where it is converted into serotonin. Without enough carbohydrate, even a high-protein diet can leave you feeling low or anxious.
Choose slow-release, fibre-rich carbohydrates such as oats, quinoa, brown rice, sweet potatoes and root vegetables. These keep energy stable and prevent the mid-afternoon slump that can make brain fog worse. Combining carbohydrates with protein and healthy fats at meals helps slow digestion and provides a steady flow of glucose to the brain.
Rather than cutting carbs, focus on choosing whole, unprocessed sources and eating them mindfully.
Why zinc and other nutrients matter
Amino acids cannot support your mood or focus unless your body can process them properly. This is where minerals and vitamins come in.
Zinc is particularly important. It activates the enzymes that turn tyrosine into dopamine and tryptophan into serotonin. Without enough zinc, the body struggles to complete these conversions, which can leave you feeling flat or anxious. Zinc also helps keep the receptors in your brain healthy so that these neurotransmitters can do their job effectively.
Good sources of zinc include pumpkin seeds, seafood, hemp seeds and cashews. Women who experience ongoing stress or poor digestion are often low in zinc, as stress and low stomach acid reduce absorption.
Other essential nutrients include:
Vitamin B6, B12 and folate for neurotransmitter production and energy.
Magnesium for relaxation, GABA function and sleep quality.
Iron for oxygen transport to the brain.
Selenium to protect the brain from oxidative stress and support thyroid balance.
Choline, found in soy, sunflower seeds and eggs if tolerated, for memory and learning.
When these nutrients are present in the diet, the brain can use amino acids efficiently to make the chemicals that support mood and clarity.
Is creatine energy for a tired brain?
Creatine is a naturally occurring compound made from amino acids. It is best known for its role in muscle performance but is also vital for brain energy.
The brain uses creatine to regenerate ATP, the molecule that powers all cell activity. Oestrogen normally supports this process, but when oestrogen levels fall, energy production becomes less efficient. This can make mental effort feel tiring.
Adding more creatine through fish, small amounts of meat, or a vegan supplement can improve concentration and reduce fatigue. Research shows that creatine can enhance working memory and cognitive resilience, especially in women experiencing hormonal changes.
Balancing blood sugar and improving sleep
The brain needs a steady supply of glucose for energy. Skipping meals, relying on caffeine or eating sugary snacks causes blood sugar spikes and dips that mimic anxiety and worsen brain fog.
Eat balanced meals every three to four hours, combining protein, healthy fats and fibre to keep energy stable.
Sleep is equally important. It is during deep sleep that your brain consolidates memories and clears waste. When progesterone falls, sleep can become lighter and less restorative, but simple steps can help.
Keep your bedroom cool and dark, avoid screens in the hour before bed, and try a calming routine such as stretching or breathing exercises. Herbal teas like lemon balm or chamomile and magnesium-rich foods such as pumpkin seeds or dark leafy greens can also support better rest. For more detailed sleep support, check out the sleep webinar here.
Building stress resilience
You cannot remove all stress from life, but you can build resilience to it. Gentle movement, outdoor time and grounding rituals all help the nervous system recover from daily strain.
Activities such as yoga, walking or swimming improve circulation and oxygen delivery to the brain. They also stimulate the release of brain-derived neurotrophic factor, which helps form new neural connections and supports memory.
Breathwork, journalling and mindfulness practices calm the stress response and reduce cortisol levels. Even a few minutes of deep breathing or writing down tomorrow’s to-do list can clear mental clutter and promote better sleep.
Confidence and self-belief
Brain fog can do more than affect concentration. It can undermine confidence. Many women feel embarrassed when they lose words or forget small details. This is not a lack of intelligence or ability. It is a reflection of temporary biochemical shifts.
Oestrogen and progesterone influence serotonin and dopamine, which affect motivation and reward. When these hormones drop, your sense of confidence can drop too. This does not mean you are less capable. It means your brain chemistry needs support.
Being gentle with yourself, setting realistic expectations and remembering that this phase is transitional can make a huge difference. Confidence returns as your energy, sleep and focus improve.
Practical steps for a clearer mind
Eat for clarity
Include protein at each meal from a variety of sources such as fish, tofu, beans, lentils and seeds.
Support key nutrients
Focus on zinc, magnesium, iron, selenium, B-vitamins and choline through whole foods or supplements if needed.
Balance blood sugar
Eat regularly and combine protein, healthy fats and fibre for sustained energy.
Protect your sleep
Create a calm evening routine, keep your bedroom cool and avoid screens late at night.
Move every day
Walk, stretch, practise yoga or do light resistance exercise to increase circulation and reduce stress.
Manage stress
Include daily grounding practices such as journalling, breathwork or time outdoors.
Check underlying factors
If fog or fatigue persist, it may help to test thyroid, iron, vitamin B12 and hormone levels with a healthcare professional.
The takeaway
Brain fog in perimenopause is not permanent and it is not all in your head. It is a signal from your body that your brain and hormones are seeking a new balance. By eating well, sleeping deeply, and calming your stress response, you can restore clarity and confidence.
This stage of life does not have to mean losing your sharpness. It can be an opportunity to slow down, nourish yourself and reconnect with what your body truly needs. When you do, the fog lifts and a steadier, clearer version of yourself emerges.
For more support in navigating the perimenopause journey, watch the Peri/Menopuase webinar or join the Women’s Health Programme starting 3rd November.
