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Brain Fog, Headaches & More — Here's What Happens To Your Brain On Your Period

Kristen Willeumier, Ph.D.
May 11, 2021
Kristen Willeumier, Ph.D.
By Kristen Willeumier, Ph.D.
Kristen Willeumier, Ph.D., is a renowned neuroscientist with extensive research expertise in brain function, injury, and disorders.
Brain Fog, Headaches, what happens to your brain during your period
Image by Javier Díez / Stocksy
May 11, 2021

While menstruation commonly occurs for one week every month, the entire menstrual cycle tends to last much longer. The timeline will vary from person to person, as there's no such thing as a "normal" menstrual cycle. Regardless of how long or short your cycle is, though, your body and your brain will experience hormonal changes.

The cyclical rise and fall in levels of ovarian hormones (estrogen and progesterone) can have a profound impact on cognitive behavior. So, if you tend to have headaches, brain fog, minor memory flubs, or other brain-related side effects during your menstrual cycle, you're definitely not alone. Here are a few possible side effects and why they occur: 


Brain fog

Both estrogen and progesterone are low during menses, which can lead to the common symptoms of "brain fog." This might include the inability to concentrate, increased absent-mindedness, failure to recall or retain information, difficulty reading, and fatigue. It may also lead to insomnia and fluctuations in mood, including anxiety and depression.



Headaches during your period may be due to the fluctuation in hormone levels, low iron (from loss of blood), dehydration, or stress.

If headaches occur on a monthly basis, work with your endocrinologist or OB/GYN (ideally with a functional medicine background) to find a solution. If you have an unusually heavy menstrual cycle, speak with your physician about taking an iron supplement. You can also increase your intake of iron-rich foods at this time, which include animal sources (red meat and poultry), fish (salmon and tuna), as well as plant sources (beans, tofu, and pumpkin seeds).  

If dehydration is causing your headaches, be sure to consume enough fluids to meet your daily hydration needs. According to the Institute of Medicine, women require 2.7 liters of fluids (90 ounces) daily, 20% of which can come from hydrating foods, like fruits and vegetables. 


Memory lapses

Estrogen can affect the growth and survival of new neurons in the hippocampus (a brain region responsible for memory and learning). Therefore, decreased levels of estrogen during the menstrual cycle (typically the luteal phase) may affect the ability to think clearly and remember new information. There is also evidence that estrogen has an effect on the prefrontal cortex1, an area of the brain essential to working memory (i.e., short-term memory) and executive function. 



The endogenous fluctuation of estrogen and progesterone during the menstrual cycle affects the cerebellar networks in the brain2. The cerebellum—which is involved in motor coordination and higher-order cognitive functions—is an important target for estrogen.  

Therefore, when estrogen levels are low (i.e., during the late luteal phase through menses), this may result in an impact on motor function and cause you to be clumsy or drop things more often. 

Ways to effectively cope with PMS symptoms. 

  1. Get restorative sleep and take a nap if you need to. 
  2. Try a breathwork practice, yoga, or tai chi to relax and reduce stress.
  3. Embrace a brain-healthy diet rich in antioxidant foods including acai berries, blackberries, blueberries, raspberries, carrots, yams, kale, spinach, cucumber, salmon, legumes, walnuts, chia, flaxseed, and green tea. 
  4. Meet your daily hydration needs with clean, pure water. You can give it a boost with a squeeze of lemon or drink a fresh-squeezed green juice. Here: 5 foods to add to your water for extra hydration.
  5. Exercise, or get up and move every hour.
  6. Make a to-do list so that you feel more organized.  
  7. Enjoy a relaxing Epsom salt bath to relax the muscles.
  8. Take a multivitamin, omega-3 fatty acids, and vitamin D to support neurotransmitter production and promote a balanced mood. 

Bottom line. 

The brain is an important target for estrogen actions, particularly with regards to working memory and spatial memory. Progesterone has a calming effect on the brain and has been shown to regulate cognition, mood, inflammation, mitochondrial function, and neurogenesis in the brain. Since both of these hormones are fluctuating during the menstrual cycle, it's not uncommon to experience minor brain-related side effects. 

There are natural ways to support brain health that may help mitigate these symptoms, but if any of these issues are persistent or concerning, reach out to a functional medicine doctor or a holistically minded OB/GYN for extra guidance.

Kristen Willeumier, Ph.D. author page.
Kristen Willeumier, Ph.D.

Kristen Willeumier, Ph.D. conducted her graduate research in the laboratory of Neurophysiology at the University of California, Los Angeles and the laboratory of Neurogenetics at Cedars-Sinai Medical Center. She received M.S. degrees in Physiological science and Neurobiology and a Ph.D. degree in Neurobiology from the University of California, Los Angeles. She was a postdoctoral scientist in the Department of Neurology at Cedars-Sinai Medical Center where she continued her work in the field of neurodegenerative disease. Willeumier was the recipient of an NIH fellowship award from the National Institute of Mental Health and has presented her work internationally. She currently lives in Los Angeles, CA.