The neuroscience behind brain fog, overwhelm, forgetfulness, and hormonal change
Somewhere in their late 30s or 40s, many women begin quietly asking themselves the same question:

What is happening to my brain?

They describe:

Forgetting words mid-sentence
Walking into rooms and losing track of why they’re there
Feeling mentally “slower”
Struggling to focus
Feeling emotionally overwhelmed by things they used to manage
Increased anxiety, sensory sensitivity, or emotional reactivity
Exhaustion that sleep doesn’t seem to fix

And for many women, the most distressing part is this:

“I don’t feel like myself anymore.”

For a long time, these experiences were often dismissed as:

Stress
Burnout
Ageing
“Just hormones”
Anxiety
Being too busy

But the latest neuroscience research is telling us something important:

Perimenopause and menopause are not just reproductive transitions. They are also significant neurological transitions.

And the brain fog many women experience is very real.

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First: What actually happens hormonally?
One of the biggest misconceptions is that hormones simply “drop” in a straight line.
That’s usually not what happens.
During perimenopause
Perimenopause is the transition phase leading up to menopause, and it can begin years before periods stop completely.
During this time:

Progesterone is often the first hormone to decline
Ovulation becomes less predictable
Oestrogen can fluctuate dramatically, sometimes high, sometimes crashing low

This hormonal instability can have a profound effect on the brain and nervous system.

Many women notice:

Increased anxiety
Disrupted sleep
Irritability
Sensory overwhelm
Poorer concentration
Emotional reactivity
Brain fog

And often, these symptoms arrive before women even realise they’re in perimenopause.

Why oestrogen matters to the brain

Oestrogen does far more than regulate the reproductive system.

It also plays a major role in:

Memory
Attention
Emotional regulation
Stress response
Brain energy production
Neurotransmitter functioning

Research shows oestrogen supports:

Serotonin
Dopamine
Acetylcholine
Neural connectivity
Brain glucose metabolism
Anti-inflammatory processes within the brain

In simple terms:

Oestrogen helps the brain function efficiently.

So when oestrogen fluctuates, and later declines more significantly during menopause, many women experience measurable cognitive and emotional changes.

The brain fog is real

One of the most validating shifts in recent research is this:

Researchers are increasingly recognising menopausal brain fog as a legitimate neurological experience, not simply “stress” or women being dramatic.

Women commonly report:

Word-finding difficulties
Reduced working memory
Difficulty multitasking
lower processing speed
Mental fatigue
Trouble concentrating
Feeling cognitively “offline”

Some researchers describe menopause as a period of temporary neurological vulnerability, where the brain is adapting to major hormonal changes.

And importantly: This does not usually mean dementia.

That fear is incredibly common among women experiencing perimenopausal brain fog, particularly high-achieving women who suddenly feel less cognitively sharp than they once did.

But for most women, these cognitive changes are related to:

Hormonal fluctuation
Sleep disruption
Stress system activation
Inflammation
Nervous system overload
Reduced brain energy efficiency

… not permanent brain damage.

Does menopause “kill brain cells”?

This is where online conversations can become misleading.

The current evidence does not suggest menopause causes widespread brain cell death in the way social media sometimes portrays.

What researchers are actually finding is more nuanced.

Oestrogen loss may contribute to:

Reduced synaptic connectivity
Changes in brain energy metabolism
Increased neuroinflammation
Reduced efficiency in certain brain networks

In other words: The brain may not communicate as smoothly or efficiently during this transition.

Some studies also suggest the brain may attempt to adapt by increasing oestrogen receptor sensitivity, almost like trying to “catch” whatever oestrogen remains available.

The brain is not simply shutting down.

It is adapting.

Why so many women feel emotionally different too

Perimenopause doesn’t just affect memory or concentration.

It can also profoundly impact:

Emotional regulation
Stress tolerance
Nervous system capacity
Sensory processing

Many women describe feeling:

“Raw”
Emotionally flooded
Less resilient
More anxious
More reactive
More sensitive to noise, mess, conflict, or overwhelm

This makes sense neurobiologically.

Hormonal changes interact directly with:

The stress response system
Cortisol regulation
The limbic system
Autonomic nervous system functioning

For women with:

ADHD
Trauma histories
Chronic stress
Burnout
High caregiving loads
Perfectionism or over-functioning patterns

… perimenopause can sometimes amplify pre-existing nervous system vulnerabilities.

Many women who have “held it together” for decades suddenly discover the strategies that once worked no longer seem sustainable.

One of the most important things I tell clients

There is nothing wrong with you.
You are not failing.
And you are not imagining this.

Many women are navigating:

Careers
Parenting
Caregiving
Invisible emotional labour
Relationship strain
Chronic stress
Nervous system depletion

…while simultaneously moving through one of the biggest neuroendocrine transitions of their life.

Of course the nervous system can begin to struggle under that load!

The hopeful part: The brain is adaptive

The female brain is remarkably adaptive and neuroplastic.

For many women, symptoms improve significantly once hormonal fluctuations stabilise.

And there are evidence-based ways to support the brain and nervous system during this transition, including:

Improving sleep quality
Reducing chronic stress load
Strength training and regular movement
Blood sugar regulation
Adequate protein intake
Nervous system regulation work
Trauma-informed therapy support
Social connection and co-regulation
Appropriate medical support where indicated

Some women also benefit from menopausal hormone therapy (MHT/HRT), though this is highly individual and should always involve proper medical assessment and discussion with a qualified healthcare professional.

Final thoughts

One of the most powerful shifts happening in women’s health research right now is this:

Menopause is increasingly being understood not just as a reproductive transition, but as a brain transition.

And perhaps one of the most healing things we can offer women is validation.

Because so many women have spent years quietly wondering:

“Why can’t I cope the way I used to?”

When often, the better question is:

“How much has my brain and nervous system been carrying for far too long?”

If this resonated with you, and you’re finding yourself feeling overwhelmed, cognitively exhausted, emotionally reactive, or unlike yourself lately, you are not alone.

At The Sage Society, we work from a trauma, attachment, and nervous system-informed lens to help support women through periods of stress, transition, burnout, and emotional overwhelm.

Because sometimes healing starts not with “pushing harder”…

…but with finally understanding what your brain and nervous system have been trying to communicate all along.

Learn more about working with Gabby

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Why so many women feel like they’re “losing their mind” during perimenopause

Many women entering perimenopause begin experiencing brain fog, overwhelm, forgetfulness, anxiety, and emotional exhaustion, often wondering, “What is happening to me?” Emerging neuroscience research suggests menopause is not just a reproductive transition, but also a significant neurological one. This article explores the latest research on oestrogen, brain function, nervous system overload, and why so many women suddenly feel unlike themselves during this stage of life.