Brain fog and menopause

What it looks like

Brain fog isn't a single symptom but a cluster that often tends to appear together:

• Struggling to find the right word or name
• Losing your train of thought mid-sentence
• Trouble concentrating on one thing at a time
• Misplacing objects or forgetting appointments
• A general reduction in cognitive speed that some women describe as their brain feeling "like cotton wool"

What's happening in the brain in menopause?

Oestrogen receptors are present throughout the brain, including in the hippocampus, which plays an important role in memory formation and retrieval. As oestrogen fluctuates and then declines through perimenopause and menopause, hippocampal function can be affected, and memory and concentration are what many people notice first.

Oestrogen also plays an important role in other parts of the brain, such as the prefrontal cortex (important for attention, decision-making and language) and the amygdala, which plays a key role in processing emotions. Fluctuations in oestrogen can therefore affect all of these cognitive processes, resulting in symptoms of brain fog.

Oestrogen also helps neurons form new connections, reduces inflammation in the brain, and supports how efficiently brain cells use glucose for fuel. Much of what we now know comes from brain-imaging work by Dr Lisa Mosconi, alongside researchers such as Dr Roberta Brinton. Their findings show that as oestrogen levels change in perimenopause and menopause, the brain temporarily changes how it produces and uses energy, essentially finding alternative fuel sources while it adapts to a new hormonal baseline. Mosconi describes it as a kind of renovation of the brain: neural circuitry built for the usual menstrual cycle is no longer needed, so the brain reorganises, resulting in brain fog while this reorganisation is underway.

However, it isn't necessarily bad news. In Mosconi's research, a substantial group of postmenopausal women showed brain activity and memory performance comparable to before menopause. The changes that take place in perimenopause and menopause can be looked at as a period of adjustment, or "structural reorganisation," rather than one of decline.

Why it happens

As well as the changes in the brain that can affect memory, concentration and attention, other symptoms of perimenopause and menopause can also contribute to brain fog.

Sleep disruption, night sweats, anxiety and low mood relating to menopause can all cause or worsen brain fog.

Poor sleep alone is enough to affect memory at any age, and disturbed sleep is extremely common through perimenopause and menopause.

We also have to consider the impact of the pressure and demands of navigating life and work. It's well documented that stress can significantly affect memory, concentration and attention, and the stress of navigating menopause cannot be underestimated.

Brain fog isn't unique to menopause

Interestingly, brain fog is not exclusive to perimenopause and menopause. In fact, in one study, 28% of adults (both male and female) reported experiencing brain fog, which is one reason it shouldn't automatically be attributed to hormones without considering what else might be at play.

Other common contributors include

• Poor or disrupted sleep, from any cause (although menopause itself often disrupts sleep)
• Fatigue and burnout, particularly alongside a heavy caring or work load
• Low mood and depression, which often present as slowed thinking rather than obvious sadness
• Anxiety and chronic stress
• Long Covid, where cognitive symptoms are among the most widely reported lasting effects; around a third of people still report brain fog a year after infection, and pooled data across studies puts cognitive and related mental health symptoms at roughly one in five people affected
• Thyroid dysfunction
• Low ferritin or iron deficiency, even without anaemia
• Diabetes
• Certain medications, including some used for allergies (including certain antihistamines), sleep or pain
• Vitamin B12 or vitamin D deficiency
• Alcohol

This is why brain fog symptoms should be carefully assessed rather than assumed to be due to perimenopause or menopause.

Blood tests including thyroid function, ferritin, B12 and iron levels can often be helpful for excluding other medical causes.

Looking at sleep, mood, stress and diet alongside a conversation about where you are in the menopause transition, with a GP or a menopause specialist, is vital to ensure that the whole picture can be explored.

Is this the start of dementia?

This is the underlying fear of many women who experience symptoms of brain fog. For the vast majority, the answer is no. Menopausal brain fog can certainly be problematic, but unlike dementia, it usually does not impact basic day-to-day functioning (such as the ability to wash, get dressed and follow simple instructions), and it tends to improve once the menopausal transition is complete, reflecting a temporary shift in brain function rather than decline or the beginnings of dementia.

There is still a lot that is unknown about brain fog and changes in female brains across the lifespan. More studies are needed, as well as a clearer, shared definition of what menopausal brain fog involves, in order to support further research.

However, one thing that is clear is that forgetfulness, poor concentration and difficulties with attention during perimenopause are usually very different to the changes we see occurring in early dementia, and having brain fog during menopause does not mean you are more likely to develop dementia in the future.

What can I do about brain fog? What helps?

Thanks to ongoing research, there are some good-quality, evidence-based recommendations that can help manage and reduce the symptoms of brain fog.

Sleep

Disrupted sleep has a huge impact on cognitive function. Night sweats, anxiety and racing thoughts all interrupt sleep through perimenopause, and poor sleep magnifies the symptoms of brain fog. Treating the sleep disruption, whether through managing night sweats, addressing anxiety, or improving sleep habits, often eases cognitive symptoms alongside it.

Move regularly

Physical activity supports blood flow to the brain and has a well-established link to mood and cognitive function in midlife. Strength training also increases production of BDNF (brain-derived neurotrophic factor), which plays an important role in memory and cognitive function, meaning that when you build muscle through strength training, you're building cognitive function as well.

Reduce the cognitive load as much as possible

Multitasking is harder for every brain during times of transition. Writing things down, using reminders, and focusing on one task at a time is a sensible accommodation that can take some of the pressure off.

Normalise brain fog and be kind to yourself

Once we become aware of our brain fog symptoms, we notice them more, through processes psychologists call attentional selectivity and confirmation bias. This often means we feel our symptoms are worsening, simply because we're more aware of where our memory and cognitive speed aren't as sharp as before. On top of this, attentional control theory tells us that worrying about brain fog takes up precious cognitive energy, which can exacerbate symptoms. The work of Professor Aimee Spector has shown that the more we can normalise the symptoms of this transition, while being compassionate to ourselves, the more manageable and less problematic brain fog becomes.

Will hormone replacement therapy (HRT) help my brain fog?

Yes and no. HRT will ease many of the menopausal symptoms and processes that contribute to brain fog, such as sleep disruption, hot flushes, night sweats and mood changes.

There is currently no good-quality evidence confirming that HRT directly improves brain fog, but many women (not all) feel their symptoms of brain fog improve after starting HRT due to the overall symptom improvement, although this can take three to six months.

Some women find that HRT eases their overall symptom burden enough that they have the energy and motivation to make the lifestyle changes mentioned above, which then help cognitive health in the longer term. Discover more about HRT.

Will testosterone help my brain fog?

The research to date shows that testosterone does not offer any significant benefit compared with placebo when it comes to improving brain fog symptoms in menopause. However, a proportion of women (not all) who use testosterone do report anecdotally that it helps their cognitive function, so your menopause specialist may discuss a trial of testosterone as a potential option for you, if appropriate.