Is Perimenopause Making You Forgetful? Why Women in Perimenopause Double-Check Everything

You walk out of the house.

Two minutes later you wonder:

“Did I take my phone?”

You check your bag. It’s there.

Later you leave for a trip and check for your passport… five times.

You start writing an email, then switch tasks halfway through.

You’ve heard about brain fog in perimenopause - but this feels different.

Is this just hormones?

Or is this something more serious?

Let’s break down what’s actually happening in the perimenopausal brain.

What Happens to the Brain in Perimenopause?

Perimenopause isn’t just about declining estrogen and progesterone.

It’s about fluctuating estrogen.

Those fluctuations affect key brain regions:

• Prefrontal cortex (focus, organization, decision-making)

• Hippocampus (memory consolidation)

• Dopamine pathways (motivation, follow-through)

• Serotonin systems (mood stability)

• GABA signaling (calm vs. anxiety)

While progesterone directly enhances calming GABA signaling through its neurosteroid metabolites, estradiol also influences GABAergic systems in the brain by modulating inhibitory receptor dynamics and interneuron activity. This modulation can affect the balance of excitation and inhibition in neural circuits, which contributes to cognitive and emotional changes during hormonal transition.

Research from neuroscientist Lisa Mosconi shows that during the menopause transition, the brain undergoes a temporary shift in energy metabolism, while your estrogen receptors are getting used to lower baseline levels. It has actually been found that estrogen receptors are multiplying during this time so that they can soak up all the estrogen possible. 

The brain becomes slightly less efficient at using glucose.

That means your brain is more vulnerable to:

• Blood sugar dips

• Sleep disruption

• Stress spikes

• Inflammation

Why Do You Keep Checking Things Repeatedly?

The “Did I take my keys?” phenomenon is usually caused by:

1. Reduced Working Memory Confidence

Your short-term memory encoding becomes less reliable during estrogen fluctuation.

You probably did take your phone.

But your brain isn’t 100% confident that it did.

So it checks.

2. Mild Anxiety Amplification

Estrogen modulates serotonin and GABA.

When levels fluctuate, anxiety circuits become slightly more reactive.

Checking behavior often reflects hypervigilance - not dementia.

3. Dopamine Instability

Estrogen enhances dopamine signaling.

When dopamine dips:

• Task completion weakens

• Mental tracking weakens

• Focus scatters

Many women in perimenopause experience executive dysfunction that resembles mild ADHD - even if they’ve never had it before.

Why It’s Often Worse Late Morning 

Many women notice increased distractibility late morning.

Here’s why:

• Morning cortisol is declining

• Liver glycogen may be depleted

• Blood sugar may be dipping

• Brain glucose sensitivity is heightened during perimenopause

The female brain is extremely glucose-dependent.

Even mild blood sugar fluctuations can impair:

• Word recall

• Task follow-through

• Working memory

• Cognitive confidence

If you get hungry at 11 AM, your brain may already be under mild metabolic stress.

That’s when:

• You forget why you entered a room

• You check your bag

• You start three tasks at once

Is This an Early Sign of Alzheimer’s?

In most healthy perimenopausal women: No. Early Alzheimer’s typically involves:

• Progressive worsening (not fluctuation)

• Getting lost in familiar places

• Language breakdown unrelated to fatigue

• Functional decline

• Others noticing significant change

According to the Alzheimer's Association, early dementia is persistent and progressively impairing - not stress-sensitive and hunger-sensitive.

Perimenopausal cognitive changes are typically:

• Fluctuating

• Sleep-sensitive

• Stress-sensitive

• Improved with hormonal stabilization

Estrogen is neuroprotective and supports mitochondrial function, glucose metabolism, and synaptic health. Researchers like Roberta Brinton have shown that estrogen supports brain energy production and resilience.

Why HRT Doesn’t Always Fully Fix Forgetfulness in Perimenopause

But why doesn’t HRT then completely fix that problem? Hormone Replacement Therapy can significantly help for sure. But it doesn’t override everything.

Even with optimal estradiol levels, cognitive symptoms may persist if there is:

• Blood sugar instability

• High cortisol

• Chronic sleep disruption

• Low ferritin

• Low B12

• Thyroid conversion issues

• Neuroinflammation

• High toxic load

HRT stabilizes hormonal input. It does not automatically correct metabolic or inflammatory drivers.

Why Word-Finding Gets Worse at Night

Evening word-finding difficulty is extremely common. I definitely am experiencing this…

Especially if you:

• Speak multiple languages

• Work in cognitively demanding environments

• Are tired

• Take progesterone at night

  
  

Language switching requires strong executive function.

The prefrontal cortex is the first area to fatigue when:

• Glucose is low

• Sleep pressure rises

• GABA tone increases

This is cognitive fatigue - not structural decline.

When Should You Be Concerned?

Seek medical evaluation if you experience:

• Progressive decline over months

• Getting lost in familiar places

• Forgetting major events entirely

• Functional impairment

• Others noticing significant personality change

Fluctuating, context-sensitive forgetfulness is typically hormonal and metabolic.

How to Improve Perimenopause Brain Fog

If you want to stabilize your cognitive function and forgetfulness in perimenopause:

Support Brain Energy

• Eat 25–35g protein at breakfast

• Add a protein-rich snack before 11 AM

• Avoid long fasting windows if symptomatic

• Check out my cookbook to optimally support blood sugar balance in peri and menopause

Optimize Sleep

• Address nighttime cortisol spikes

• Use progesterone strategically

• Stabilize blood sugar before bed

Reduce Neuroinflammation

• Resistance training

• Omega-3 intake

• Address gut health

• Reduce environmental toxic load

Support Dopamine

• Strength training

• Morning light exposure

• Structured work blocks

• Creatine supplementation

The Bottom Line

If you’re in your 40s or early 50s and occasionally checking for your phone, feeling scattered, or searching for words at night:

Your brain is not failing.

It is recalibrating.

Perimenopause narrows your stress tolerance window.

When blood sugar drops, sleep suffers, or stress rises - executive function wobbles.

But this phase is usually reversible with proper hormonal, metabolic, and nervous system support.

If you're navigating perimenopause and want to understand how hormones, blood sugar, inflammation, and stress intersect - that’s exactly the work I do.

You don’t have to guess whether it’s “just hormones” or something more.

Your brain deserves the same strategic support as the rest of your body.