Brain Fog & Memory

The word is right there. You can almost see it. You’ve used it a thousand times. And it simply… won’t come.

Or you walk into a room and forget why. Or you lose your train of thought mid-sentence. Or you read the same paragraph three times and still can’t retain it.

“Brain fog” is one of the most commonly reported—and often most distressing—symptoms of perimenopause. It can make you feel like you’re losing yourself, like your mind is betraying you, like something is seriously wrong.

Let me tell you what’s actually happening.

This Is Real

What’s most affected:

• Verbal learning—taking in new information through words
• Verbal memory—retrieving that information later
• Word-finding—accessing the vocabulary you know you have
• Processing speed—how quickly you can work through cognitive tasks

This isn’t imagination. It’s not stress (though stress makes it worse). It’s not “just aging.” There’s a hormonal component, and we can measure it.

Why This Happens

Your brain is rich with estrogen receptors. When estrogen fluctuates wildly—as it does during perimenopause—multiple brain systems are affected:

Neurotransmitters shift. Estrogen influences serotonin, dopamine, and acetylcholine—all essential for mood, motivation, and memory.

BDNF decreases. Brain-derived neurotrophic factor is like fertilizer for neurons. Estrogen supports its production. When estrogen is erratic, BDNF levels can drop.

Blood flow changes. Estrogen helps maintain healthy blood flow to the brain. Fluctuations can affect this.

Inflammation increases. Estrogen has anti-inflammatory effects. When it’s unstable, neuroinflammation may increase.

Research also shows that higher FSH and LH levels—which rise as your ovaries become less responsive—correlate with worse cognitive performance. It’s not just estrogen; it’s the whole hormonal symphony going out of tune.

The Part That Matters Most

For most women, this improves.

Cognitive symptoms tend to be worst during the chaotic transition of perimenopause—when hormones are swinging wildly. Once you reach stable postmenopause, when the fluctuations settle, most women find their cognitive function returns.

The fog is typically temporary. It doesn’t mean you’re declining. It means your brain is adapting to a major neurochemical shift.

What Might Help

Address the foundations:

• Sleep profoundly affects cognition. If you’re not sleeping, your brain can’t consolidate memories or clear waste products.
• Mood matters. Depression and anxiety independently affect concentration and memory.
• Exercise increases blood flow to the brain and supports BDNF production.

Consider hormones: Some women find hormone therapy helps with cognitive symptoms, though the research is mixed. It seems to help most when started during perimenopause rather than years after menopause.

Compensate strategically:

• Write things down. Use lists. Set reminders. A symptom tracker can help you spot patterns over time.
• Give yourself more time for tasks that require concentration.
• Reduce multitasking—your brain is already working hard.
• Be patient with yourself.

What probably won’t help:

• Beating yourself up
• Pretending it’s not happening
• Assuming you’re developing dementia

When to Seek Evaluation

Brain fog during perimenopause is common and usually benign. But significant cognitive changes—especially rapid changes, or changes that affect your ability to function safely—warrant medical evaluation.

Your provider should:

• Take your concerns seriously
• Rule out other causes (thyroid issues, vitamin deficiencies, depression, sleep disorders)
• Not simply dismiss you with “it’s just menopause”

If your provider dismisses you, find another. Your brain matters.

The Fear Underneath

I know what many women fear when the fog rolls in: Is this the beginning of dementia?

For the vast majority of women, it is not. The cognitive changes of perimenopause are different from neurodegenerative disease—they’re temporary, they’re tied to hormonal transition, and they improve.

That said: if you have a family history of Alzheimer’s or specific concerns, it’s reasonable to discuss them with your doctor. Knowledge is better than fear.

You haven’t lost your mind. You’re in a fog that will lift. Your brain is doing something hard right now—adjusting to a new hormonal reality. Give it time, give it support, and give yourself grace.

The words will come back.