The forgetfulness, memory loss, dizziness, lack of concentration, mental clarity, and inability to focus are all symptoms of your brain fog. Depending on the severity of your brain fog, it can really affect your life at work, school, and in your relationships.

13 Common causes of brain fog

There are many reasons why you have brain fog.

In today’s day and age, with all that work on screen time, your eyes are taking a constant hit. This screen time can lead to poor sleep, and lack of sleep is a huge contributing factor to brain fog.

This is why you may have morning brain fog. Another factor that may cause lack of sleep is your inability to manage stress. Stress leads to many chronic conditions, and a lack of sleep, and ultimately brain fog is a major one. Both stress and a lack of sleep can also alter your hormones, thereby leading to brain fog.

What you put into your body is what you need to look into as well. Your diet can play a huge factor in your brain fog. It’s not only what you’re eating, but what you’re drinking can also cause brain fog. 
Brain fog occurs commonly after drinking alcohol, or after eating dairy, sugar, rice, fruit, bread, nuts, and pasta. Additionally, you may be deficient in certain vitamins and minerals that we cover below. Depending on some health conditions, your allergies, diagnoses, and medications to treat those allergies and diagnoses can also play an immense role in your brain fog.

Brain fog is a symptom that can be tough to nail down. Like an allergy, sometimes it’s best to start reducing the culprits that may cause it. Here, we list all the causes that may be causing your brain fog:

1. Food intolerances:

Fatigued when you wake up, exhausted by lunchtime, and completely drained when the evening rolls around? A worn-out mind quickly saps your entire body's energy levels, and fighting to keep the fog at bay can make it even worse. It can cause you to feel overwhelmed and emotionally drained, making it impossible to overcome your responsibilities and problems. Feelings of detachment, apathy and all kinds of personal and working life can become devastating.

Food intolerance is not simple because any one individual can be allergic to anything as far as we are concerned, but common intolerances are gluten, wheat, dairy, sometimes it can be other things such as foods high in FODMAP. stands for Fermentable Oligo-, Di-, Mono-saccharides And Polyols. These are a group of short-chain carbohydrates that are poorly absorbed. In people with gastrointestinal symptoms, a diet high in FODMAPs can induce diarrhea and/or constipation, bloating, wind, and abdominal pain. There are claims that sugar intolerance is also a thing! Apart from sugar, dairy rice, bread, nuts, and pasta also cause brain fog.

2. Anxiety:

Take this cause with a grain of salt. Most people who have brain fog will get diagnosed with anxiety/depression or something along those lines, and it tends to be a false-positive, but sometimes it is actually down to anxiety and depression and only you can find and eliminate that cause in yourself. Additionally, the anxiety can cause brain fog as well. Anxiety can cause you to have racing thoughts thereby leading to your brain working in overdrive. This overthinking can lead to lack of proper sleep and thereby cause brain fog.

3. Stress:

Similar (but not exactly) to anxiety, stress and chronic stress can definitely be a cause of brain fog. Blood pressure, immune system weakening, and depression may be triggered by chronic stress. Additionally, mental tiredness and fatigue can also be caused. It gets harder to think, reason and concentrate when your brain is exhausted due to stress.

4. Vitamin deficiency:

Your brain fog may be because of a deficiency in vitamins. A lack of Vitamin B12, C, D, and Omega-3 Essential Fatty Acids may be a huge culprit. You may have a vitamin B12 deficiency if you have poor memory and feel you have been in a constant state of fogginess. This is one of the most frequently experienced deficiencies of vitamins affecting 40% of adults. Vitamin D can lift your mood, eliminates brain fog and depression.

Omega-3 Essential fatty acids are found in high levels of brain matter. The most important sources of food are wild fatty fish, such as sardines, salmon and trout, which are critical to your memory and overall brain health and functions, and still lack in your diet. Where your brain fog is particularly bad, choose an addition that contains a high concentration of DHA (Docosahexaenoic acid). DHA is the most useful to your brain of all omega-3s. It is a significant structural component of the cells of the brain, especially the brain area — the area of the brain that is connected to memory , language, abstraction, creativity, judgment, emotion and attention.

5. Gut issues:

Gut issues can also be the cause, and it is the broad term for many issues that could go wrong there, such as SIBO, Leaky gut, bad microbiome, etc. In the intestine and brain, poor intestinal health can result in poor brain health and related symptoms. The intestinal line is intended only for the bloodstream to convey certain compounds. Intestinal permeability is caused if the lining of the digestive tract becomes overweight, allowing the bloodstream toxins, undigested foods and other disease agents. This triggers a systemic inflammation immune cascade, increasing the risk of food sensitivity, inflammatory effects, pain and autoimmune illness. There's no damage stopping. Leaky gut is linked to the "leaky brain," which is also over permeable by the blood / brain barrier, a protective membrane around the brain. This enables pathogens to enter the brain, resulting in an inflammatory cascade.

6. Injuries, wisdom teeth, and trapped nerves:

It has recently been substantiated that pinched nerves (typically those in the back or neck) can also cause brain fog. Don't ignore any aches, or pains as it may be a pinched nerve and may be the cause. This nerve pain also exists behind your wisdom teeth. The pain is causing your brain cells to focus on the pain instead of the task at hand. Ultimately, brain cells, or neurons, don’t communicate well with each other to focus on the task at hand. This causes brain function to slow down and diminish, giving you brain fog.

7. Mold spores:

It has recently been substantiated that pinched nerves (typically those in the back or neck) can also cause brain fog. Don't ignore any aches, or pains as it may be a pinched nerve and may be the cause. This nerve pain also exists behind your wisdom teeth. The pain is causing your brain cells to focus on the pain instead of the task at hand. Ultimately, brain cells, or neurons, don’t communicate well with each other to focus on the task at hand. This causes brain function to slow down and diminish, giving you brain fog.

8. Hormonal imbalances:

Hormonal Balances are also known to cause brain fog, and this can be in any form, such as dopamine deficiency, and many, many others. The cause of a hormonal imbalance can also be due to hypothyroidism. Additionally, progesterone and estrogen hormone levels during pregnancy or periods are also a major reason for brain fog.  Whereas during menopause, a decrease in estrogens can also cause poor concentration and lack of focus and trouble concentrating on single task that are all symptoms associated with brain fog.

For men, testosterone plays a huge role. It affects a huge range of brain features, including memory. Testosterone is responsible for more than physical effects. Indeed, brain fog or a general decline in memory and focus is one of the most noticeable effects of low testosterone in men.

9. Sleep disorders:

Sleep apnea and other sleep disorders can be another cause of brain fog as it interrupts sleep, which can leave you energyless and foggy. Sleep deprivation disrupts the ability of our brain cells to communicate, resulting in temporary mental deficiencies that influence memory and visual perception. 

10. Fibromyalgia:

Fibromyalgia is easily capable of causing brain fog due to its harsh and difficult nature, and has it’s own term, called Fibro Fog. Fibromyalgia causes aches and pains all over the body, as well as fatigue, sleep, and mood issues. It can also lead to problems with memory or thinking clearly. These cognitive difficulties are common: Research suggests more than half of people with fibromyalgia show a decline in memory and clear thinking.

11. Medications:

Medications play a huge role in brain fog. Many medications affect brain function and play a vital role in your brain fog. There are a few medications that directly affect your brain fog. These are:

Benzodiazepines: . Prescribed to help people with sleep and anxiety, they are directly correlated to memory loss.

Sedatives: These sleep drugs can cause an impair in judgement and thinking. Examples are Ambien, Sonata, Lunesta.

Anticholinergics: These are over the counter sleep aids. They have the chemical property of blocking the neurotransmitter acetylcholine and links directly to memory loss. Examples are Sedating antihistamines, such as diphenhydramine (brand name Benadryl), The “PM” versions of over-the-counter analgesics (e.g. Nyquil, Tylenol PM); the “PM” ingredient is usually a sedating antihistamine.

Antipsychotics and mood-stabilizers: Prescribed for schizophrenia, dementia, or alzheimers, these can dampen brain function and cause memory loss and lack of focus. Examples include risperidone, quetiapine, olanzapine, and aripiprazole.

12. Multiple sclerosis:

Multiple Sclerosis, known as MS for short, also causes brain fog is due nature with the condition. Since MS is a central nervous disease affecting the brain, disturbances in thinking play a role. Fuzzy thinking may be one of the most discouraging symptoms of MS. The condition is a psychological confusion that often strikes without warning, in this case called brain fog. Patients usually report a lack of concentration, poor memory or decreased cognition. More than 50% of patients are brain fog at some point during their illness, according to the National Multiple Sclerosis Society.

13. Drinking:

Intoxicants, such as alcohol, play a huge factor in your brain fog. After a heavy night of drinking, you’ll notice yourself not function at 100% the next day. Your brain has taken some damage during this rampage. Drinking alcohol is directly tied to loss of brain function and concentration.

Also, check these 5 ultimate treatments for brain fog. 

What vitamin deficiencies causes brain fog?

A lack of Vitamin B12, C, and D are a huge culprit of brain fog. You may have a vitamin B12 deficiency if you have poor memory and feel you have been in a constant state of fogginess. This is one of the most frequently experienced deficiencies of vitamins affecting 40% of adults. Two high risk groups are:

• The elderly with often poor nutrient absorption
• Vegetarians / vegans, since B12 is only found for animal products.


Digestive disorders and medicines that suppress the acid also increase the risk of deficiency. They may cause a vast variety of mental and neurological disorders. Antacids such as nexium, pepcid and zantac have a strong relationship with the deficiency with vitamin B12, because acid in the stomach is required to decompose and absorb vitamin B12. 

Vitamin D can lift your mood, eliminates brain fog and depression. Vitamin D deficiency is the best source of vitamin D, but few people who live in North America and much of Europe can get the real sun they need around the year. Sun exposure is the best source of vitamin D.

Our brain is a huge consumer of Vitamin C. It needs vitamin C plays the role of eliminating oxidative stress, and this is really important, as oxidative stress prevents debris clearance from the cells of the brain, promotes toxin growth, sets off inflammatory processes and leads to the death of the cells. This causes cognitive impairment, which includes memory loss and lack of concentration.

Can allergies cause brain fog?

Seasonal allergies and allergies in general cause brain fog. The reason being that people with allergies experience inflammation. And this inflammation leads to a congested nose, disrupted sleep patterns and not getting good rest. Even just a few nights of poor sleep can result in feelings of imbalance, loss of focus and exhaustion. The effects compound the longer that goes on, and you will continue to feel hazy and fuzzy.

Do you feel brain fog after eating/drinking?

Do you feel brain fog immediately after eating? Well, you’re not alone. Brain fog can happen after eating carbs. These carbs cause an inflammatory response within your gut thereby requiring the energy of your cells to focus on repairing that inflammation. This energy focus shifting towards the gut causes you to feel drowsy, hazy, and fuzzy. Some culprits include dairy, sugar, rice, bread, nuts, and pasta.

Ever had brain fog after drinking?

This is your hangover brain fog. This brain fog after drinking can be caused by beer or wine. Drinking affects the neurotransmitters in your brain. Especially the neurotransmitter GABA, which when slowed down, leads to sluggishness, speech impairment, and slower reaction time.

Why birth control can cause brain fog?

New studies have shown that birth control pills may be causing brain fog, for a couple reasons. Firstly, the birth control pills regulate your circadian rhythm and have a tendency to throw this off. Once thrown off, your sleep and wake cycles are wreaked havoc upon, causing poor sleep and fuzzy thinking. Additionally, all the hormonal changes in your body will leave you confused, distracted and unable to recall information easily, almost having the same effect as “pregnancy brain”.