Brain Fog in Perimenopause: What it Feels Like and How to Handle it

If you're in your 40s (or sometimes even late 30s) and finding it harder to concentrate, remember things, or express your thoughts clearly, you’re not imagining it. These mental shifts are common during perimenopause, and they’re often described as “brain fog”.

It’s frustrating. It can feel isolating. But it’s also a recognised part of the hormonal changes your body is going through, and there are ways to manage it.

What Is Brain Fog, Exactly?

“Brain fog” isn’t a medical diagnosis, it's a term people often use to describe cognitive changes that make thinking feel slower, foggier, or just not like it used to be.

During perimenopause, this might show up as:

Struggling to find the right word mid-sentence
Walking into a room and forgetting why
Forgetting appointments or tasks more than usual
Feeling mentally sluggish or tired, even after resting
Losing focus during reading, meetings, or conversations

These changes can feel alarming, especially if you’re used to feeling sharp and on top of things. But they’re incredibly common, and usually temporary.

Why Does Brain Fog Happen in Perimenopause?

The main reason is hormone fluctuation. During perimenopause, levels of oestrogen and progesterone rise and fall unpredictably. These hormones don’t just affect your reproductive system, they also influence how your brain functions.

Oestrogen, in particular, plays a role in:

Memory and learning
Verbal recall
Mood regulation
Sleep quality

When levels fluctuate or decline, the brain may respond with slower processing, trouble focusing, or memory lapses. Add in poor sleep (thanks to night sweats or anxiety), and the effect can snowball.

What Can Help?

You don’t need to just “put up with it.” There are practical ways to manage brain fog and support your cognitive health.

1. Prioritise Sleep

Lack of restorative sleep makes brain fog worse. If night sweats, insomnia, or anxiety are interfering, speak to your GP, treatment (including HRT or non-hormonal options) can improve both sleep and mental clarity.

2. Support Brain Health with Nutrition

A balanced diet supports brain function. Focus on:

Omega-3 fats (e.g. oily fish, flaxseeds)
Leafy greens, berries, and whole grains
B vitamins, especially B12 and folate
Staying hydrated

Caffeine and alcohol can worsen fatigue and sleep issues, so it may help to cut back or time them carefully.

3. Move Your Body

Exercise boosts blood flow to the brain, lifts mood, and improves sleep. Walking, yoga, or dancing are great easy ways to get your body moving.

4. Structure Your Day

Use tools to stay on track:

Write things down
Set reminders on your phone
Break tasks into small steps
Do one thing at a time (multi-tasking makes fog worse)

5. Try Mindfulness or Meditation

Regular practice can help you feel more grounded and focused. Even 5–10 minutes a day can improve clarity over time.

6. Consider Hormone Replacement Therapy (HRT)

For some, HRT can significantly ease brain fog, especially if it's linked to other symptoms like poor sleep or mood swings. It’s not for everyone, but it’s worth discussing with a knowledgeable GP.