PROFESSIONAL ARTICLE
26.10.2026
By: Prof. Dr. Joana Félix | Gynecologist-Obstetrician
“I walk into a room and I no longer know what I went in there for.”
“The words fail me halfway through a sentence.”
“I have no memory or concentration.”
Do you recognize any of these phrases? If so, you have probably wondered if it is stress, fatigue, burnout, or something more serious. It is called brain fog, and it is one of the most common symptoms of perimenopause, but unfortunately, it is still rarely talked about.
It is not your imagination, and science shows it!
Brain imaging studies show that during perimenopause, the brain exhibits changes similar to those seen in early Alzheimer's disease, especially in how it uses energy. This does not mean you will develop the disease. It means that what you are feeling has a biological explanation and deserves to be taken seriously.
Why does it happen?
Estrogen is essential for the brain: it plays an important role in memory, concentration, and mood. When levels of this hormone begin to drop, memory and concentration follow suit.
And all of this happens during an intense phase of a woman's life, professionally and personally. Added to the hormonal decline are:
• Stress and the burden of caring for everyone else;
• Restless nights, often interrupted by children or hot flashes;
• Physical and emotional exhaustion;
• Iron, vitamin B12, vitamin D, and other nutrient deficiencies.
It is the perfect cocktail for brain fog!
The good news: there is a solution!
The key is a holistic approach, what is now called hormonal biohacking: instead of looking at an isolated symptom, look at the woman as a whole.
In practice, what do I do in a 40+ consultation to help recover from brain fog?
• Improve sleep, because rest is essential for well-being;
• Encourage physical exercise, because it improves mood and promotes brain oxygenation;
• Manage stress and set aside time for yourself, which is not selfish, it is health;
• Order the right tests and correct the deficiencies found;
• Start safe and appropriate hormone replacement therapy for each woman.
Do not accept being told "it is your age"
For too long, women were told it was normal and that they had to put up with it. Or that it was "all in their heads". And it is, literally, but it is real!
You do not have to put up with it. Brain fog has an explanation and a treatment.
If you feel that your head is no longer the same, talk to your doctor. Ask for help and regain your well-being. Because menopause does not have to be a "pause" in your life.