Why the brain doesn’t work the week before the period…
If you’ve ever wondered why your brain seems to short circuit in the days leading up to your period, you’re far from alone. I genuinely feel like a completely different human. I know who I am, what I like and how I behave but this week, she no longer exists. Many people experience a frustrating mix of brain fog, forgetfulness, irritability, and slow thinking during this time. The good news? There are real biological reasons for this and it’s not “just in your head.” This is something I have to remind myself every time the pms/pmdd symptoms come knocking on the door, that they are not me, and next week I will feel normal. This is hard to do every month, and its even harder when you don’t fully understand the cycle so…
Let’s break down what’s actually happening inside your brain during the premenstrual phase and what you can do to feel more like yourself.
✨ The Hormone Rollercoaster
The week before your period falls in your luteal phase, when the hormones estrogen and progesterone take a sharp dip. These hormones do more than manage your reproductive system, they also influence your brain.
When they drop, neurotransmitters like serotonin and dopamine shift, which can affect:
Focus
Memory
Mood
Motivation
Mental energy
This is why your to-do list feels impossible, words slip your mind, or you feel more overwhelmed than usual. I also tend to walk into things, drop things and lose all energy for anything I usually love. It’s a bad week. :)
✨ PMS vs. PMDD: When Symptoms Hit Hard
Most people experience some version of PMS, but if your symptoms feel intense, like your brain “shuts down” or you can’t function normally, you may be dealing with PMDD (Premenstrual Dysphoric Disorder).
I started to notice that this week seemed to affect me far more than others which is when I began to research pmdd and found that these symptoms were far more common for me and I felt them way more intensely.
PMDD is less common but much more severe, and it can intensify:
Cognitive fog
Emotional sensitivity
Anxiety
Irritability
If your life feels derailed every month, this is worth exploring with a professional.
✨ Inflammation Increases
Research suggests that inflammation rises slightly in the luteal phase. Inflammation doesn't just affect the body, it can also cloud the mind, contributing to:
Sluggish thinking
Low motivation
Fatigue
This can amplify the “my brain is not working” feeling.
✨ Sleep Gets Disrupted
Progesterone’s rise and fall can interfere with sleep quality. Even if you’re sleeping the same number of hours, you may not be sleeping as deeply.
Poor sleep = poor focus, irritability, and foggy thinking.
✨ Blood Sugar Swings
Hormone shifts can also make your body more sensitive to blood sugar changes. Cue:
Cravings (the sweet treat cravings can do damage)
Energy crashes
Mood swings
Difficulty concentrating
It’s not lack of willpower, it’s your biology. I used to feel so guilty within this week, actually I still do. I’m a pretty healthy person and I prefer to not eat junk or a lot of sweet food but this week has me wanting either everything at one time or nothing at all, it’s seriously confusing. Even though the cravings can be pretty powerful I think it’s important not to give in to all of them, fake foods (sweets, chocolate, cakes) might satisfy some cravings but it won’t make the mental side of things any better. Try to focus on foods that still taste good but will also keep your energy levels and mental state pretty stable, such as banana and oat pancakes, non-refined sugar cookies, dark chocolate etc
So… What Can Help?
If this week feels like a monthly mini-meltdown, try supporting your brain (and hormones) in simple ways:
✔ Eat protein + complex carbs regularly
This keeps blood sugar stable and helps prevent crashes.
✔ Boost magnesium and omega-3 intake
Both support mood and cognitive function.
✔ Move your body
Light exercise can reduce inflammation and improve mental clarity.
✔ Prioritise sleep
Your brain needs more support during the luteal phase.
✔ Watch caffeine and alcohol
Both can make PMS symptoms worse. I still drink match during this phase as I actually feel as though it helps me in this week rather than hinders me but every one is different, it is meant to have some benefits when looking at the pms and matcha relationship. (I did a whole blog on this which you can find in the science section.)
✔ Track your cycle
Patterns make the “why am I like this?!” moments easier to predict and to manage.
When to Seek Extra Support
If your symptoms are severe, disruptive, or emotionally overwhelming, they may go beyond typical PMS. PMDD is real and treatable, and you don’t have to suffer through it alone. It’s good to know that these are all hormone changes rather than a quarter life crisis sometimes, even though it’s never an easy week. Remind yourself that your head will feel almost normal In the next week, once the red demon has left the chat.