Have you ever had trouble focusing, remembering things or thinking clearly? Many people experience brain fog at some point.          

Brain fog isn’t a medical diagnosis, but it’s a way to describe a group of symptoms that affect how you think and process information. These symptoms can affect daily life, making even simple tasks feel more difficult.

What Is Brain Fog?

Brain fog refers to problems with clear thinking. It can affect attention, memory and the ability to stay focused.

Common symptoms of brain fog include:

• Trouble concentrating
• Memory problems
• Forgetfulness
• Difficulty organizing thoughts

In some cases, brain fog may be linked to cognitive impairment, meaning the brain is not working as efficiently as it should.

Many people who experience brain fog also have mental fatigue, which can make thinking feel tiring or overwhelming.

What Causes Brain Fog?

There are many possible causes of brain fog. Some are temporary, while others may be linked to underlying health conditions.

Common causes include:

• Poor sleep
• Poor nutrition
• High stress levels
• Illness or infection (including effects on the immune system)
• Hormonal changes
• Certain medications, such as sleep aids and older antihistamines, as well as cancer treatments, such as chemotherapy

Because symptoms can overlap with other conditions, it’s important to look at the bigger picture when trying to understand what might be causing brain fog.

Medical Conditions Linked to Brain Fog

In some cases, brain fog may be connected to underlying health conditions that affect memory, concentration or how the brain processes information. Identifying and treating the underlying cause can help improve symptoms.

Conditions that may contribute to brain fog include:

• Perimenopause and menopause can affect memory, concentration and mental clarity due to changes in hormone levels.
• Hypothyroidism is an underactive thyroid that can slow metabolism and affect energy levels, thinking and memory.
• Migraines can affect concentration, memory and mental clarity before, during and even after a migraine episode.
• Multiple sclerosis (MS) is a condition that affects the brain and nerves and can lead to thinking difficulties, slowed processing and memory issues.
• Neurodegenerative conditions, such as Alzheimer’s disease, can gradually affect memory, thinking and overall cognitive function.
• Anxiety and depression can affect focus, concentration and the ability to think clearly.
• Sleep disorders, such as insomnia and sleep apnea, can disrupt rest and make it harder for the brain to function at its best during the day.
• Long COVID-19: After a COVID-19 infection, some people experience lingering brain fog that can affect memory, focus and mental clarity, likely tied to ongoing inflammation in the body.

Does Brain Fog Come From One Area of the Brain?

Brain fog isn’t caused by just one area of the brain. Instead, it involves how different parts of the brain communicate.

The brain relies on connections across multiple regions to manage focus, memory and decision-making. When these connections aren’t working as efficiently — whether due to stress, fatigue or illness — it can lead to symptoms like poor concentration or forgetfulness.

Brain fog reflects how the brain is functioning as a whole, not just one part.

When Should You See a Doctor?

Brain fog is often temporary. But if symptoms don’t improve or start to interfere with daily activities, it’s important to seek care.

See a doctor if you notice:

• Ongoing trouble remembering conversations or events
• Difficulty finding words or forming language
• Problems processing information
• Changes in mood or personality
• Difficulty completing everyday tasks

Your doctor can help identify possible causes and recommend next steps.

“Work with your healthcare team to identify the underlying contributing factors to your brain fog as this often leads to symptom improvement,” says Dr. Carroll.

Lifestyle Habits To Reduce Brain Fog and Improve Focus

Daily habits play an important role in how clearly you think. Small changes to your routine can help reduce brain fog and improve focus over time.

Try these simple strategies:

• Prioritize sleep: Quality sleep helps the brain process information and stay focused.
• Exercise regularly: Physical activity improves blood flow to the brain and supports cognitive function.
• Eat brain-boosting foods: A healthy diet that includes foods rich in vitamins and minerals, such as leafy greens, blueberries and salmon, helps support brain health.
• Manage stress: Techniques like mindfulness and deep breathing can help reduce mental strain.
• Stay organized: Using routines, lists or reminders can make it easier to manage tasks and reduce mental overload.
• Take breaks: Giving your brain time to rest can help improve focus and reduce fatigue.

Together, these habits can support cognitive function, improve mental clarity and make daily tasks feel more manageable.

When To Pay Attention to Brain Fog

Brain fog is common and often temporary, especially during times of stress, lack of sleep or illness. In many cases, improving daily habits as part of a healthy lifestyle, such as getting enough rest, managing stress and staying active, can help reduce symptoms.

However, if symptoms persist or begin to affect your quality of life, it may be time to seek care. Your doctor can help identify possible causes and treatment options.