By Dr. Jackie Piasta, DNP

If you’ve found yourself standing in the kitchen wondering why you’re there…
forgetting a familiar word mid-sentence or rereading the same email three times and still not processing it…

You’re not alone—and no, this does not automatically mean dementia.

For many women in their 30s, 40s, and early 50s, these moments are one of the most unsettling symptoms of perimenopause. Let’s talk about what’s really going on.

First, let’s say this clearly

Perimenopausal brain fog is real.
It is common.
And it is not the same thing as dementia.

That fear—“What if something is seriously wrong?”—is one we hear every single week in clinic.

What does perimenopausal brain fog actually feel like?

Patients often describe:

Word-finding difficulty (“It’s on the tip of my tongue”)
Trouble concentrating or multitasking
Short-term memory lapses
Feeling mentally “slower” or less sharp
Increased mental fatigue
Anxiety about cognitive performance

Importantly, these symptoms often fluctuate, worsen with stress or poor sleep, and most often improve as the menopause transition progresses.

Why does this happen in perimenopause?

Your brain is a hormone-responsive organ.

Estrogen plays a key role in:

Neurotransmitter signaling (acetylcholine, serotonin, dopamine)
Glucose metabolism in the brain
Blood flow and neuroprotection
Sleep regulation and mood stability

During perimenopause, estrogen doesn’t just decline—it becomes erratic. These hormonal swings can temporarily disrupt how efficiently the brain processes information.

This is not brain damage or decline, rather a brain adapting to hormonal change.

How is this different from dementia?

Perimenopausal brain fog:

Symptoms come and go
You notice the changes (self-awareness is preserved)
Daily function is intact, even if frustrating
Improves with sleep, stress reduction, time and treatment

Dementia:

Progressive and steadily worsening
Often noticed more by others than the person themselves
Interferes with daily functioning
Does not fluctuate based on sleep or stress

If you’re worried because you’re aware of the changes and distressed by them—that actually points away from dementia.

The role of sleep, stress, and mental load

Hormones don’t act alone.

Perimenopause often overlaps with:

Insomnia or fragmented sleep
Increased anxiety
Caregiver stress
Career pressure
Chronic mental overload

Sleep deprivation alone can impair memory and executive function in ways that feel dramatic. Add fluctuating hormones, and the effect is amplified.

Can hormone therapy help brain fog?

For many women, yes—when appropriately prescribed and individualized.

Evidence suggests estrogen therapy can:

Improve verbal memory and attention
Support brain metabolism
Improve sleep and mood, indirectly enhancing cognition

Hormones are not the only tool, but for the right patient at the right time, they can be transformative.

What else helps?

A comprehensive approach may include:

Optimizing sleep (often the biggest lever)
Managing anxiety and stress physiology
Addressing iron deficiency, thyroid issues, or B12 deficiency when present
Cognitive load reduction (yes, this matters)
Movement and resistance training
Nutrition that supports brain glucose metabolism

Brain fog is rarely a single-cause problem—and that’s good news, because it means there are multiple ways to help.

When should you seek evaluation?

You should talk to a clinician if:

Symptoms are persistent and distressing
You feel dismissed or told “it’s just stress”
Brain fog is paired with severe mood changes or insomnia
You want to discuss hormone therapy options
You want reassurance and a plan

The bottom line

Perimenopausal brain fog can feel frightening, but it is:

Common
Biological
Treatable
And not a sign that you are “losing your mind”

Your brain is changing because your hormones are changing—and with the right support, clarity can return.

Is This Dementia? Unpacking Perimenopausal Brain Fog