What’s Happening to My Brain?
Perimenopause brings a new hormonal environment for the female brain.
The Neuroscience of Perimenopause
If you’ve been forgetting words, losing your train of thought, or feeling mentally “foggy,” you’re not imagining it — and you’re certainly not alone. One of the most surprising symptoms of perimenopause isn’t just hot flashes or mood changes. It’s the way your brain starts to feel different.
Women often describe this shift as:
“My brain feels slow.”
“I can’t focus like I used to.”
“My words disappear mid-sentence.”
“I used to multitask easily — now it overwhelms me.”
And for women who have been high-functioning, organized, and relied upon by everyone, these changes can feel frightening. The good news? This is normal. It’s explainable. And it’s temporary.
Let’s walk through what’s actually happening inside your brain during perimenopause.
1. Your Hormones Are Changing — And Your Brain Feels It First
Here’s a representation of typical hormone behaviour in perimenopause.
Both estrogen and progesterone have powerful effects on the brain.
Progesterone is calming. It supports sleep and helps regulate the nervous system.
Estrogen helps with mood, focus, memory, working memory, and verbal fluency.
You can see from the chart above how during perimenopause progesterone steadily drops, estrogen fluctuates like a rollercoaster (not a gentle decline). Sleep becomes fragmented and your stress reactivity increases. This combination affects the nervous system in a very real, very physical way.
Your brain isn’t declining — it’s trying to adapt to internal instability.
2. Brain Fog: The Most Common (and Most Misunderstood) Symptom
Brain fog can feel like:
slower thinking
trouble focusing
difficulty starting tasks
mental “heaviness”
feeling like your mind is underwater
needing to reread things multiple times
This doesn’t mean you’re losing intelligence. Brain fog happens when the brain is dealing with hormonal instability, poor sleep, and increased stress during midlife. Your brain is doing its best with fewer resources. It’s not a decline — it’s capacity being stretched thin.
3. Word-Finding Issues: “I Know the Word…”
If you’re losing nouns, pausing mid-sentence, or mixing up words - you’re in good company. This is extremely common.
Estrogen supports the neurotransmitters involved in language retrieval. When estrogen fluctuates, the pathways that help you access words become less efficient.
The word isn’t gone.
The pathway is glitching.
Add stress or pressure — a meeting, conflict, multitasking — and retrieval becomes even harder. This is temporary, reversible, and not associated with cognitive decline.
Your vocabulary is still there.
Your brain is just under strain.
4. Multitasking Suddenly Feels Impossible
Multi-tasking?! How did I do this before?
Before perimenopause, you may have been the queen of multitasking — mentally holding everything together for everyone.
Now?
Switching between tasks may feel jarring. You might lose track of what you were doing. Two people talking at once may overwhelm you.
Why?
Because multitasking depends heavily on the prefrontal cortex, which is sensitive to hormones, sleep, stress, and emotional load.
During perimenopause, you simply have less cognitive padding.
Your brain wants to focus on one thing at a time — not because you’re less capable, but because you’re overloaded.
5. Decision Fatigue: “Why Is Everything So Hard?”
Even simple choices — dinner plans, replying to a message, scheduling something new — can suddenly feel huge.
Decision-making takes mental energy, and perimenopause reduces your available bandwidth.
Your brain is already managing:
fluctuating hormones
heightened stress
sleep disruptions
increased sensory sensitivity
So decisions that once felt easy now feel heavy. This is not indecisiveness.
It’s mental exhaustion. As your system stabilizes, this becomes easier again.
6. The Most Important Thing: This Is Temporary
Perhaps the biggest fear women have is: “Is this permanent?”
The research is clear:
cognitive symptoms during perimenopause are common
they are not associated with dementia
they improve as hormones stabilize
they respond well to support — emotional, medical, and lifestyle
Your intelligence, capability, competence, and clarity are still there. Nothing about these symptoms means you’re losing yourself. Your brain is navigating a major transition while carrying the mental load of a lifetime — and it needs more support, not more pressure.
You Deserve Support in This Stage
If you’re experiencing brain fog, overwhelm, trouble focusing, or cognitive changes, you are not failing — you’re human. The menopause transition affects every system in your body, including your brain. With support, understanding, and care, clarity returns.
You don’t have to go through this alone.
If these cognitive changes feel unsettling or unfamiliar, you may find it helpful to read my full guide to the emotional and psychological symptoms of perimenopause. It explains how shifts in hormones, sleep, and stress regulation all come together to affect the brain — and why so many women feel “not like themselves” during this transition.
The information on this website is for informational purposes only. It is not intended to be a substitute for professional medical advice, diagnosis, or treatment or to replace your relationship with your health care provider. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or seen on this site.