What Is “Brain Fog”?

What science says about it, and what you can do to help your memory, focus and mood.

Photo by Milad Fakurian on Unsplash

If you’ve ever walked into a room and thought, “Why am I here?”, lost track mid-sentence, or struggled to remember the name of the Netflix show you just binged… you’ve probably muttered those famous two words: brain fog.

It’s not an official medical diagnosis, but for many women in perimenopause and menopause, brain fog feels very real, like someone replaced your sharp mind with porridge. The good news? Science is catching up, and there are practical ways to support your brain.

What Is Brain Fog?

Brain fog is a cluster of cognitive symptoms, think memory slips, poor concentration, word-finding problems, and mental sluggishness. Research shows that up to two-thirds of women in the menopause transition report some level of cognitive change.

It often appears in perimenopause, when hormones fluctuate the most, and tends to settle a little in postmenopause. Importantly: brain fog is not dementia. For most women, it’s temporary and reversible.

Why Does It Happen?

Scientists don’t point to just one cause. It’s more like a cocktail of changes happening at once.

• Hormone shifts: Estrogen plays a big role in brain regions tied to memory and focus (like the hippocampus). When estrogen drops or fluctuates, it can affect neurotransmitters, synapses, and even brain energy metabolism.

• Sleep disruption: Hot flushes and night sweats wreck sleep, and poor sleep wrecks memory consolidation. No surprise fog rolls in after too many nights awake.

• Mood changes: Anxiety, stress, and depression, all more common in perimenopause - amplify fogginess.

• Vasomotor symptoms: Some studies suggest the more severe your hot flushes, the more likely your cognition takes a hit.

• Age & stage: Brain fog is often worst during the transition itself, not years after, hinting that it’s the hormonal rollercoaster, not just aging, that’s the main culprit.

What Does Science Say Helps?

There's no miracle cure, but plenty of strategies (some medical, some lifestyle) have solid evidence behind them:

• Hormone Therapy (HRT): Some studies suggest that when started in perimenopause or early menopause, HRT may support verbal memory and attention. It’s not prescribed just for brain fog, but can be a side benefit if you’re using it for hot flushes or bone health. Always a doctor’s conversation.

• Sleep first: Treating night sweats, creating a cool/dark sleep environment, and keeping consistent sleep routines all help your brain function better.

• Move your body: Exercise boosts blood flow to the brain, supports neurotransmitters, and improves sleep and mood. Aerobic activity + strength training is the golden combo.

• Eat brain-friendly foods: A Mediterranean-style diet rich in omega-3s, colourful veg, legumes, nuts, and olive oil supports vascular and brain health.

• Mind-body tools: Mindfulness, CBT, journaling, or even just talking to someone, these reduce stress and improve concentration.

• Track your symptoms: Keeping a journal or using an app makes it easier to see patterns and talk to your GP about what’s really going on.

Bottom Line

Brain fog in perimenopause isn’t “all in your head.” It’s a mix of hormone changes, poor sleep, mood shifts, and stress - and it affects millions of women. The fog usually lifts, but you don’t have to just wait it out. With a mix of lifestyle tweaks, symptom management, and appropriate medical support, you can sharpen your memory, boost your mood, and get your focus back.

Your brain is still brilliant. Sometimes it just needs a little extra TLC while your hormones recalibrate.

If you would like to read some more information on the changes in the body during perimenopause and menopause, I found these 2 books to have a great balance between science and reality.

The New Menopause by Dr Mary Claire Haver

https://amzn.to/41TKf3z

The Definitive Guide to the Perimenopause and Menopause by Dr Louise Newson https://amzn.to/3VfECsM

If you or someone you care about is experiencing cognitive changes, it is always wise to get this checked out by a medical professional.

Always in your corner,

Laura x

References

• Weber MT, Maki PM, McDermott MP. Cognition and mood in perimenopause: a systematic review. Menopause. 2012;19(6):618-626. DOI link

• Mosconi L, Rahman A, Diaz I, et al. Menopause impacts human brain structure, connectivity, energy metabolism, and amyloid-beta deposition. Sci Rep. 2021;11:10867. Link

• Maki PM & Joffe H. Cognitive function during the menopausal transition. Menopause. 2009;16(4):694-700.

• Harvard Health Publishing. Menopause and brain fog: What’s the link? 2022. Link

• International Menopause Society. Brain Fog in Menopause: A Guide for Healthcare Professionals. 2022. PDF