PMS and brain fog: what’s really going on?

The mental load of your cycle

Many people associate PMS with bloating or mood swings, but cognitive symptoms are often overlooked. These are all the different mental events involved in thinking, learning, and comprehending. If you find yourself staring at emails blankly, misplacing your phone, or forgetting basic tasks in the week before your period, you’re not alone.

This phenomenon – often called brain fog – is increasingly recognised as a real and disruptive part of the PMS and PMDD experience. It’s frustrating, especially when it clashes with work demands or makes you feel less like yourself

 

What causes brain fog in PMS?

In the luteal phase (the second half of your menstrual cycle), levels of oestrogen and progesterone fluctuate. These hormones don’t just influence your reproductive system – they also interact with neurotransmitters in your brain.

A drop in oestrogen, in particular, can affect serotonin and dopamine – key players in mood regulation, memory, and focus. This shift can lead to forgetfulness, slower thinking, and mental fatigue.

Some small studies have also found changes in brain activation patterns during the luteal phase, particularly in areas linked to executive function. This involves skills that you use to manage everyday tasks like making plans, solving problems and adapting to new situations.

 

Brain fog, PMDD and emotional overload

For people with PMDD, brain fog can be more severe and emotionally charged. The inability to concentrate or make decisions often contributes to feelings of overwhelm, self-criticism or panic.

'When I can’t think clearly, I start doubting myself. It’s like my brain just disappears for a week’ – Evelyn community member

This combination of cognitive symptoms with mood changes is part of why PMDD can be so easily misdiagnosed as anxiety or depression.

Learn why PMDD is often misdiagnosed.

 

It's not laziness - it's hormonal

Brain fog isn’t a personal failing or a lack of motivation. It’s a neurochemical response to hormonal changes. That means the solution isn’t just trying harder – it involves supporting your brain and body in the right way.

Strategies that may help include:

• Tracking your cycle to anticipate when fog is likely
• Nutritional support with B vitamins, magnesium, omega-3s
• Movement and blood flow to boost mental clarity
• Reducing cognitive load during fog-prone days
• Supplements like Evelyn's Super Regular®, designed to support neurotransmitter and hormonal balance

Explore how Super Regular® can support clarity and focus.

 

Looking after your mind - and your expectations

One of the hardest aspects of brain fog is the internal narrative it can trigger. Many people feel ashamed or anxious about their cognitive dips, especially in high-pressure environments.

Building self-awareness around your cycle is important and can be empowering. It lets you plan, pace yourself, and respond with compassion instead of frustration. Remember, your capacity hasn’t disappeared – it’s simply shifting with your hormones.

 

What next?

• Use a symptom tracker to get to know your personal brain fog pattern
• Explore gentle, cycle-friendly ways to improve clarity

 

You might also like:

• PMS and insomnia
• Types of PMDD
• PMDD symptoms checklist

 

References:

• NHS: Premenstrual syndrome
• IAPMD: Understanding PMDD
• PubMed: Hormonal influences on brain function

 

Disclaimer: This content is for informational purposes only and is not intended as medical advice. Always speak to a qualified healthcare professional about any health concerns.