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Brain fog: What is it, what are the symptoms and what can we do about it?

August 5th 2021 / Melanie Macleod / 0 comment


Image: Getty

Not just a symptom of menopause, brain fog is more common than you might think. Luckily there are simple ways to clear the clouds

Do you sometimes find yourself unable to concentrate, easily distracted or struggling to remember things? You could have brain fog – and you’re not alone. A study by UCL showed that brain fog is among the most common symptoms of long Covid and Google searches for 'Covid brain fog' are up 2,750 per cent on last year.

Long Covid isn’t the only cause of brain fog, though. It could also be down to hormone imbalances, poor sleep or anxiety, among other causes. We spoke to doctors and nutritionists about brain fog symptoms to look out for and what we can do to ease that cloudy feeling. The good news is, you could be back to your sharp-minded self in no time.

What is brain fog and what are the symptoms?

“Brain fog is when you’re feeling less mentally sharp than usual,” explains dietitian Lola Biggs, who works with supplement brand Together Health. “It can affect everything from our attention span to our memory and makes us feel distracted, sluggish, tired, forgetful and unable to focus.” You might also feel spaced out or confused and have difficulty completing simple tasks, or find it difficult to form new thoughts or express what you’re thinking, Lola continues.

Struggling to multi-task is also a common symptom of brain fog, says consultant gynaecologist Dr Anne Henderson, who works with supplement brand A.Vogel.

“Forgetting words and being unable to follow a simple plot on television or calculate easy sums are all examples of brain fog too,” adds psychologist Dr Meg Arroll. “Brain fog can disrupt all areas of a person’s life.”

What causes brain fog?

1. Covid or other illnesses

“Post-viral exhaustion is quite common as we rarely give ourselves times to recover after an infection,” says nutritionist Alison Cullen. There's no concrete research on why Covid could cause brain fog but an article published by Harvard Medical School stated that damage to lungs, heart, kidneys, or other organs as a result of Covid "can impair thinking and memory and cause brain fog. For example, how can you think clearly if you’re feeling fatigued and your body is aching?"

2. Anxiety and stress

People who suffer from anxiety will often struggle with brain fog too. “Anxiety and stress can lead to high cortisol levels,” explains Lola. “High levels of this stress hormone over a long time have been shown to kill brain cells and decrease the rate at which new brain cells are made.”

3. You’re pregnant

Baby brain is a real thing. “During pregnancy it’s normal to feel overwhelmed by decision-making, but our calming hormone progesterone which is released during pregnancy, wants us to relax into our instincts, something we’re generally not good at,” explains Natasha Richardson, herbalist and founder of natural period care brand Forage Botanicals. “Our desire to be productive clashes with the hormone that wants us to relax, which can create a feeling of brain fog.”

4. You’re dehydrated

“Dehydration is probably the simplest and most prevalent cause of brain fog,” says Alison. “Even mild dehydration can cause chaos in the brain, as well as severely reducing energy levels.”

5. You’re perimenopausal

Hormone fluctuations that we see during perimenopause can lead to a foggy feeling or being disassociated and hazy in the memory department, says Alison.

“Brain fog can be driven by a decline in oestrogen, which we see a dip of in perimenopause,” adds Dr Anne Henderson.

Testosterone mustn’t be forgotten either - it also drops as we age. “Testosterone is important for clarity and helping with a sharp mind and we don’t often think about the impact of this on brain fog and memory function,” adds Tania Adib, consultant gynaecologist at The Medical Chambers.

6. You’re pre-menstrual

In the same way perimenopause hormone fluctuations can cause brain fog, so too can pre-menstrual hormones. “Brain fog naturally worsens during the premenstrual stage of our periods as our energy reduces and the body prepares for rest, but often doesn't get it,” says Natasha.

7. You’ve got allergies

“Some foods, such as fermented foods, tomatoes and some fish, are high in histamine which some people, including those who are allergy-prone, have an issue with processing in the body,” explains nutritionist Daniel O’Shaugnessy. “A symptom of this can be brain fog.”

8. You’re not sleeping well

Often a sign of perimenopause (thanks night sweats!), but something we all suffer with from time to time, bad sleep can really bring on brain fog. “Lack of sleep plays a massive part in cognitive function,” says Dr Anne Henderson. Sleeping against your natural circadian rhythm is also a cause of brain fog.

“Without proper sleep cycles your body doesn’t refresh and repair and won’t be able to file away the day or jettison waste from the brain tissue,” says Alison Cullen. “This results in waking groggy, unrefreshed and struggling to focus.”

9. You’re not active enough

We all know the feeling of lethargy when you’ve done nothing all day and it can bring on the brain fog too. If we don't move enough your brain doesn’t get the oxygen rich blood it needs to support memory function, says Lola. Regular exercise boosts circulation to the brain and helps memories to stick.

10. You’re lacking in B vitamins

B vitamins are vital for healthy thought processes,” says Dr Sarah Brewer, medical director for HealthSpan.

The three B vitamins most often linked with brain health are B6, B9 and B12. “These are required in the manufacture, maintenance and repair of brain tissue, cells and neurons,” says Lola.

What can we do about brain fog?

1. Eat more fish

“Aim to eat at least two portions of fish per week, of which one is oily,” says Dr Sarah Brewer. “These provide omega 3 fats which are important for brain health.” If you’re vegan, there are plant-based omega 3 supplements. Try Bare Biology's Vim and Vigour Vegan Omega 3 and Astaxanthin supplements, £35 for 60 capsules. They're made from algae and are squidgy capsules that are easy to swallow.


2. Try supplements

B1, B6, B12 and folic acid support healthy thought processes, while magnesium helps contribute to normal psychological function, says Dr Sarah. To up your levels, try HealthSpan’s High Strength Vitamin B Complex, £8.95 for 120 capsules, which comes highly recommended by Dr Meg. We also rate Together Health’s Vitamin B21 Shiitake Mushroom, £8.54 for 30 capsules.


If you think your brain fog is related to PMS, we recommend Forage Botanicals' Premenstrual Peace Drops, £22.99. The tincture which you drop into your mouth include passionflower and hawthorn berry to calm the nervous system and support your focus, rose to lift mood and liquorice to stop feelings of overwhelm leading to brain fog.

Daniel points out that it’s important to identify the cause of your brain fog by speaking with a nutritionist to identify if there are any imbalances in your body. “There are supplements to support cognition but these will be a drop in the ocean if you have imbalances.” He namechecks lion’s mane to help with brain health. Try Centred's Organic Lion's Mane Mushroom Extract, £32 for 60 capsules.


3. Sort out your sleep

Easier said than done, but if you can get your sleep on track you’re onto a winner. “As soon as sleep is addressed brain fog and cognition improve very quickly,” confirms Dr Anne Henderson. Read our article on 15 ways to get a better night's sleep and see if your slumber improves this evening.

Alison recommends trying A.Vogel’s Domeasan Valerian Hops Oral Drops, £10.49, to improve your chance of a good sleep cycle. We also love JS Health's PM+ Formula supplements, £24.99 for 30 tablets. They're strongly lavender scented and designed to promote deeper sleep, soothe the nerves and help you relax more easily. Ingredients include magnesium, chamomile, passionflower and lavender oil.


4. Stay hydrated

You don’t need us to tell you how much water you should be drinking every day. But we will. Alison says to aim for 1.5 litres of plain water. “You’ll notice an improvement to brain for within a few days,” she says.

5. Exercise more

It’s difficult to motivate yourself to move when you’re feeling dopey, but you’ll feel all the better for it. If you don’t want to go to the gym or pound the pavement, simply walk around the room or wave your arms around regularly to get your blood circulation going and fire up your brain. Cold water swimming is known to be particularly effective in clearing brain fog, as Rebekah Brown, founder of perimenopause supplement Mpowder discovered: "I felt an instinctive pull to swim outside and noticed a lot of my peers in midlife were heading to the open water too. It has a real impact on brain fog, bone and joint ache and energy levels."

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The bottom line

Brain fog is likely to be down to a number of causes, from changes in hormones to dietary factors (such as a lack of B vitamins) to lifestyle factors such as lack of sleep or chronic stress. “If you’re experiencing brain fog make sure you’re getting good quality sleep, try some stress management exercised and consult a nutrition expert to check for deficiencies,” says Dr Meg Arroll.

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