Brain fog is characterized by confusion, forgetfulness, and a lack of focus and mental clarity. It is avoidable and treatable. Learn what to do about it.
Brain fog is not a medically recognized term, but is a commonly used phrase that sums up feelings of confusion, forgetfulness, and a lack of focus and mental clarity.
Having brain fog is fairly common, but it’s not normal.
When you feel foggy, unfocused, and like you just can’t think, your brain is sending an important signal that there’s an issue in your life that needs to be addressed.
The causes of brain fog generally fall into one of two main categories — either it’s lifestyle-related or a side effect of a medical condition or medication.
In this article, we take an in-depth look at the eight main causes of brain fog.
And we give you specific steps to get your brain back on track quickly.
Brain Fog Cause #1: You Are Eating the Wrong Foods
One of the first things you may think when your brain gets foggy is “Was it something I ate?”
And often you’d be right.
Here are some of the many ways the food you eat could be behind your fuzzy thinking.
Refined carbohydrates like sugar and high fructose corn syrup send your blood sugar level skyrocketing up, then crashing down.
And since your brain uses glucose as its main source of fuel, this puts your brain on a roller coaster ride — first too much, then too little glucose.
Low brain glucose leads to brain fog, mood swings, irritability, tiredness, mental confusion, and impaired judgment.
Chronically high blood glucose levels lead to insulin resistance and diabetes, both of which have been linked to Alzheimer’s. (1)
The average American consumes 156 pounds of added sugar per year. (2)
Don’t be one of them!
Learn more —
The Role Sugar Plays in Depression and Anxiety
The low-fat diet fad has backfired, making us the fattest people who have ever walked the earth.
Your brain is largely comprised of fat, about 60% by dry weight, and low-fat diets have been as disastrous for our brains as they’ve been for our waistlines. (3)
According to Dr. Datis Kharrazian, author of Why Isn’t My Brain Working?, when you don’t eat enough dietary fat, the brain starts to literally digest itself for the raw materials it needs to create essential brain chemicals.
Neurologist Dr. David Perlmutter, author of the bestselling book Grain Brain, found that nothing was worse for his patients’ brains than a low-fat diet.
Glucose is usually the brain’s main fuel source, but our brains are quite happy to burn fat which he calls “super fuel” for the brain.
That’s why he recommends eating a diet roughly 50% fat from healthy sources like nuts, avocados, coconut oil, olive oil, wild salmon, eggs, and grass-fed meat.
Note that this list does not include vegetable oils like sunflower, safflower or canola oil.
Canola oil especially is high in pro-inflammatory omega-6 fatty acids which contribute to brain inflammation.
And you don’t need to be concerned about dietary cholesterol being bad for your brain.
Your brain contains a lot of cholesterol and too little of it increases your risk of suicide, depression, and dementia. (5)
You read that right.
Avoiding dietary cholesterol puts your brain at risk.
Learn more —
Brain Fog After Eating? These Are the Worst Culprits
Consuming foods you’re allergic or sensitive to can certainly put you in a mental fog.
The average American gets two-thirds of their calories from wheat, corn, and soy, and these are among the most common food allergies. (6)
The other top allergy-causing foods are dairy, eggs, shellfish, peanuts, and tree nuts.
If you suspect that you react adversely to any foods you normally eat, cut them out of your diet for a week or two and notice how you feel.
Keep in mind that these foods are often lurking in processed and restaurant foods, so avoiding them is tricky.
FoodAllergy.org has compiled an extensive list of hidden sources of top food allergens.
Go to their food allergens page and select the food in question.
You’ll find comprehensive information on foods to avoid, plus unexpected sources.
Wheat is a class unto itself as a brain fog culprit.
Mayo Clinic found that celiac disease, an autoimmune disorder triggered by gluten, goes hand in hand with dementia. (7)
But it’s not only people diagnosed with celiac disease that suffer from brain fog when they eat wheat.
Dr. William Davis built a compelling case against wheat for both your waistline and your brain in his blockbuster book Wheat Belly.
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According to Dr. Davis, the wheat we eat today bears little resemblance to the “the staff of life” consumed by our ancestors.
Gluten, a protein in wheat that makes dough stretchy, is considered the worst culprit, but there are over 1,000 other proteins in wheat that can trigger negative reactions as well.
If you decide to cut wheat out of your diet, expect to experience some unpleasant, but temporary, withdrawal symptoms.
Gluten breaks down into byproducts that bind to morphine receptors just as opiates do. (11)
Anytime you eat processed food, restaurant food, or fast food, you are almost certainly getting more salt, sugar, fat, and food additives than you might think.
Two of the worst kinds of additives for your brain are MSG and artificial sweeteners.
MSG (monosodium glutamate) is a known neurotoxin found in most processed foods.
Generally the saltier the food, the more MSG it will contain, with some of the worst offenders including canned soups, salty snacks, and ramen noodles.
Alarmingly, MSG is ubiquitous yet is not required to be put on food package labels! (12)
Innocuous-sounding ingredients like “seasoning,” “spices,” or “natural flavors” can contain hidden MSG.
When you see the words “hydrolyzed protein” or a variation thereof, that food almost certainly contains MSG.
This is common in “healthy” foods like veggie burgers.
MSG can cause brain fog and other brain-related symptoms including headaches, mood swings, dizziness, anxiety, and depression. (13)
Learn more —
You can find a list of ingredients that always contain MSG in our article on neurotoxins in food.
Another group of additives to stay away from is artificial sweeteners.
They haven’t made anyone thinner but they’ve caused a lot of other health problems.
Aspartame is made from three brain-damaging chemicals — aspartic acid, phenylalanine, and methanol.
Original studies were falsified to hide the fact that animals fed aspartame developed seizures and brain tumors, but it received FDA approval anyway. (14)
Sucralose is no better.
It’s made from bonding sugar to chlorine, making it a toxic chlorocarbon.
Common neurological side effects besides brain fog include headaches, migraines, dizziness, anxiety, depression, and tinnitus. (15)
Drinking enough water seems like common sense, yet 75% of Americans are thought to be chronically dehydrated. (16)
Your brain is 75% water by volume and even mild dehydration will affect your ability to think clearly. (17)
It takes only 2% dehydration to affect your attention, memory and other cognitive skills. (18)
Ninety minutes of sweating can shrink the brain as much as one year of aging! (19)
The effects of dehydration on the brain can be so noticeable that they mimic the symptoms of dementia. (20)
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Coffee and tea offer a lot of health benefits and can help you stay alert and focused.
But the downside of the caffeine in these drinks is that it’s addictive.
So if you get cut off from your supply, either on purpose or by circumstance, you can experience withdrawal symptoms that include brain fog, headache, fatigue, and even flu-like symptoms like nausea and vomiting. (21)
If you enjoy caffeinated drinks, as most of us do, consume moderately and strategically to avoid caffeine highs and subsequent crashes that can leave you jittery, irritable, and mentally foggy.
The Simple Solution: Eat Real Food
You will avoid most of the brain fog causes mentioned above by minimizing processed food and eating real food instead.
Food journalist Michael Pollan succinctly summed up a healthy diet in his bestseller In Defense of Food: An Eater’s Manifesto:
“Eat food. Mostly plants. Not too much.”
By “food” Pollan means things that your ancestors would recognize as food — vegetables, fruit, nuts, beans, meat, eggs, and fish — NOT the processed foods that make up the majority of items in the grocery store.
Following this one rule will reduce your load of sugar and food additives while increasing the healthy foods your brain needs to thrive.
Food quality matters and so does food quantity.
While skipping meals can leave you with a fuzzy brain, so can eating too much at one sitting.
If you’ve ever felt comatose after a big meal you know what I mean.
Brain Fog Cause #2: Nutritional Deficiencies
Maybe you already eat healthy, but your thinking is still fuzzy.
Then you might want to take a look at which supplements could help.
You may be shocked to learn that nutritional deficiencies are not a thing of the past!
Your brain needs all essential nutrients to operate smoothly, but some deficiencies are more likely to manifest themselves as brain fog.
Vitamin B12 Deficiency
If your memory is poor or you’re in a constant state of brain fog, you may have a vitamin B12 deficiency.
This is one of the most common vitamin deficiencies, affecting an estimated 40% of adults. (22)
Vitamin B12 deficiency is a serious matter and should not be taken lightly since it can lead to a wide spectrum of mental and neurological disorders. (23)
Digestive disorders and the use of acid-suppressing medications also increases your risk of deficiency.
Learn more —
How Vitamin B12 Benefits the Brain
Vitamin D Deficiency
Vitamin D can lift your mood, banish brain fog and depression, improve memory, and increase problem-solving ability. (29)
Over 1 billion people worldwide are deficient in vitamin D. (30)
Sun exposure is the best source, but few people who live in North America and much of Europe can realistically get the sun they need year-round.
So most people benefit from taking a vitamin D supplement.
Omega-3 Essential Fatty Acids
Omega-3 essential fatty acids are found in high concentrations in the brain.
They are crucial to memory and overall brain health and function, yet are widely lacking in our diet. (31)
The best dietary sources are wild-caught fatty fish like sardines and salmon.
If these aren’t a regular part of your diet, consider taking an omega-3 supplement.
Particularly when brain fog is a problem, choose one with a high concentration of DHA (docosahexaenoic acid).
Of all the omega-3s, DHA is the most beneficial for your brain.
It’s a major structural component of brain cells, especially of those in the cerebral cortex — the area of the brain associated with memory, language, abstraction, creativity, judgment, emotion and attention.
Learn more —
The Brain Benefits of Omega-3 Fats
Take a Multivitamin
The Harvard School of Public Health recommends that all adults take a multivitamin supplement as insurance to fill any nutritional gaps. (32)
And so do we.
Brain Supplements for Brain Fog
If you’ve met your brain’s basic nutritional needs but still aren’t feeling mentally sharp, you may want to try a supplement designed to boost brain power.
Here are some brain supplement ingredients that are specifically good for addressing brain fog.
Arctic root (Rhodiola rosea) is a highly regarded herb in traditional Chinese medicine.
It’s one of a handful of adaptogenic herbs — remedies that increase your resilience to stress.
The Vikings used it to increase physical and mental stamina. (37)
If you have low energy, depression, or anxiety along with brain fog, it might be a good choice for you.
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Since it raises levels of acetylcholine, a neurotransmitter responsible for memory and learning, it’s especially important to take if your brain fog is caused by any medications that work by blocking this essential brain chemical. (45)
(We’ll discuss more about how medications cause brain fog shortly.)
This safe and effective cognitive enhancer also protects the brain from free radical damage and reduces brain inflammation. (48)
Don’t let the world “kola” in the name mislead you into thinking it is a stimulant — this is a relaxing herb that contains no caffeine.
If you have brain fog and often feel tired but wired, you might benefit from taking a magnesium supplement.
Up to 75% of Americans don’t get enough of this “master mineral” that plays a role in over 600 biological functions. (49)
There are many forms of magnesium to choose from.
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The best form to counteract brain fog is magnesium l-threonate which, unlike most forms, easily crosses into the brain. (50)
The worst form is magnesium sulfate, the kind found in Epsom salts.
It’s good for soaking your feet but not for taking internally.
It has been known to cause brain fog! (51)
Vinpocetine is related to a compound found in the periwinkle vine (Vinca minor), a flowering vine that’s been used to treat memory loss since medieval times.
Doctors in Europe find it even more effective than Ginkgo biloba, which is generally thought to be the best all-around herbal memory supplement.
Brain Fog Cause #3: Lack of Quality Sleep
At least 40 million Americans suffer from over 70 different sleep disorders. (55)
If you have brain fog, you may be one of them.
Sleep is critical to the way your brain works in both the short and the long term.
While you sleep, cerebral fluid rushes in, “power washing” your brain, clearing it of debris. (56)
It’s during sleep that you consolidate memories so you can remember what you learned the previous day. (57)
Every day you lose brain cells, but every night you have the opportunity to create new brain cells — provided you are getting enough high-quality uninterrupted sleep. (58)
Just one bad night can affect your memory, concentration, coordination, mood, judgment, and ability to handle stress the following day.
According to Dr. Alexandros Vgontzas, director of the Penn State Hershey Sleep Research and Treatment Center, losing one night of sleep affects your mental performance as much as being legally drunk. (59)
Getting adequate sleep can go a long way towards curing many cases of brain fog.
Brain Fog Cause #4: Chronic Stress
Stress has become a weird badge of honor in our society.
Being stressed is wrongly equated with being productive, popular and successful.
But, in fact, stress puts you at greater risk for every major disease you hope you never get including dreaded brain diseases like dementia and Alzheimer’s.
Chronic stress leads to anxiety, depression, poor decision making, insomnia, and memory loss.
Too much of the stress hormone cortisol leads to a surplus free radicals — unattached oxygen molecules — that damage brain cell membranes, causing them to lose normal function and die. (60)
Cortisol interferes with the formation of new brain cells. (61)
Stress causes brain cells to prematurely commit suicide.
The best stress reduction technique that offers significant added brain benefits is meditation.
Over 20 million Americans meditate regularly.
The US Marines use meditation to help troops deal with stressful situations they face on the job.
“It’s like doing pushups for the brain,” one general says.
Corporate executives at General Mills, Target, Google, Apple, Nike, HBO, Procter & Gamble, and Aetna Insurance use it to maximize their brain health and fitness.
Meditation can make you happier, smarter, and more resilient to life’s ups and downs.
Regular meditators experience improved focus and concentration, greater creativity, stress reduction, and better sleep.
Research shows it can actually decrease your biological age by 12 years! (62)
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Mind-Body Relaxation Techniques
Meditation is not the only proven way to conquer stress.
Many people don’t have the patience for traditional meditation since it can take years to master.
Brainwave entrainment technology is a shortcut to get similar benefits quickly and easily.
You simply put on your headset and listen.
Other proven relaxation techniques to consider include diaphragmatic breathing, progressive muscle relaxation, self-hypnosis, Emotional Freedom Technique (EFT), and autogenic training.
You might even want to try one of the latest personal biofeedback devices such as the emWave2, Muse, NeuroSky, or Thync.
Most of these techniques can deliver noticeable stress relief within a few minutes
Brain Fog Cause #5: Physical Inactivity
Physical exercise increases endorphins and gets more glucose and oxygen flowing to the brain.
Physical exercise burns off the stress hormone cortisol and stimulates new brain cell formation.
Recent research shows that physical exercise may be the single most important thing you can do for the health and function of your brain. (63)
You don’t need to exercise strenuously to give your brain small energy boosts throughout the day.
Walking is one of the best brain exercises to clear your mind. (64)
You’ve probably heard that too much sitting is very bad for your brain and your overall health.
In fact, sitting has been called “the new smoking.”
But Dr. Joan Vernikos, a former NASA physician and author of Sitting Kills, Moving Heals, discovered the simplest “exercise” ever to counteract the ill effects of sitting.
The laughably easy way to counteract sitting is simply standing up frequently on and off throughout the day.
While working with NASA astronauts, she discovered that this works even better than walking or other forms of exercise.
Brain Fog Cause #6: Toxins in Your Home
We live in a sea of untested and unregulated chemicals.
Of the 80,000 new chemicals we have placed into our environment in the past 100 years, only a few hundred have been tested for safety. (65)
Toxins are lurking in your home, in the water you drink, and the air you breathe.
Toxins like formaldehyde and PCBs (polychlorinated biphenyls) outgas from your carpet, furniture, and mattress.
Molds, dust, pet dander, pollen, perfume, air fresheners, cigarette smoke, and household cleaners get trapped inside the average home.
And this chemical stew can cause brain fog, fatigue, and memory loss.
While you can’t control the air outdoors or at work, you can control the air you breathe at home.
Switch to natural cleaning products and personal care products, don’t smoke inside, unplug the air fresheners, and run a HEPA air filter in your bedroom to lighten your toxin load while you sleep.
Brain Fog Cause #7: Underlying Health Conditions
We started with unhealthy lifestyle factors that cause brain fog since everyone has to eat and sleep, and faces some stress in their lives.
But for many people, an underlying health condition is the root cause of their cognitive issues.
If you ask your doctor “What causes brain fog?,” the answer will almost certainly be unsatisfactory.
There is no clinical definition of brain fog, nor is there any objective brain fog test that can be administered.
But your doctor can test you for underlying health conditions that could be the source of your problem.
Brain fog is such a common side effect of a few medical conditions that they have their own condition-specific brain fog term.
A common side effect of chemotherapy used to treat cancer is a type of brain fog dubbed “chemo fog” or “chemo brain.”
The American Cancer Society’s official stance is that chemo brain is caused by a combination of the disease itself, treatments, sleep problems, hormonal changes, depression, and stress. (68)
When researchers scanned patients’ brain activity before and after chemo treatments, they found chemotherapy caused observable changes in brain function indicating that chemotherapy itself plays at least some role in mental decline. (69)
Brain fog is one of the most common complaints of people with fibromyalgia and chronic fatigue syndrome (CFS).
Many say their fibro fog is more of a disability than their pain and fatigue. (70)
People with CFS are sometimes dismissed as being hypochondriacs and told that their problems are “all in their head.”
Stanford University researchers recently found distinct differences between the brains of patients with CFS and those of healthy people which should help put these unfortunate ideas to rest. (71)
Lupus fog is a term used to describe the cognitive impairments that almost always appear with systemic lupus erythematosus (SLE). (72)
In some people, lupus fog is constant but more often it waxes and wanes along with other lupus symptoms. (73)
The brain fog that accompanies thyroid disorders hasn’t been labeled as “thyroid fog” … yet.
According to Harvard Medical School, more than 12 million Americans have thyroid disease, many of whom still remain undiagnosed. (74)
Both hypothyroid (low) and hyperthyroid (high) conditions can cause brain fog.
Other Health Conditions That Cause Brain Fog
There are many other conditions and diseases that list brain fog as a symptom including:
- adrenal fatigue
- brain injuries
- candida albicans
- chronic pain
- heavy metal toxicity
- hepatitis C
- hormonal imbalances
- irritable bowel syndrome
- Lyme disease
- multiple sclerosis
- neurodegenerative disorders
- neurotransmitter imbalance
- nutritional deficiency
- rheumatoid arthritis (RA)
- seasonal allergies
- substance abuse
- substance withdrawal
Learn more —
How to Minimize Menopause Brain Fog Naturally
Brain Fog Cause #8: Prescription & OTC Medications
Every medication carries some risks.
Brain fog is one of the most commonly reported side effects of prescription and over-the-counter (OTC) medications.
Statin cholesterol-lowering drugs and prescription sleeping pills are notorious for causing memory loss.
Learn more —
Read about prescription medications known to cause cognitive problems in Drugs That Cause Memory Loss (& what you can do).
Typical side effects of anticholinergic drugs include brain fog, forgetfulness, and inability to concentrate. (76)
It’s not only prescription medications you have to watch out for.
Many popular over-the-counter (OTC) drugs also work by blocking acetylcholine including Benadryl (for allergies), Pepcid AC (for acid reflux), and Tylenol PM (for pain and insomnia). (77)
Finding Your Personal Brain Fog Solution
As you can see, there are innumerable causes of brain fog.
Finding your personal solution will take some trial and error, but having a clear mind again will make it worth your while!
Here’s a checklist to get started.
- Experiment with your diet to see if any specific foods or food additives are to blame. Start with eliminating the most obvious offenders which includes processed foods — the source of sugar, unhealthy fats, and additives — and foods high on the allergy/sensitivity scale.
- Introduce plenty of healthy fats into your diet — nuts, olive oil, coconut oil, avocado, and fatty fish — since they are important nutritional building blocks for a healthy brain.
- Get regular, high-quality sleep. Poor sleep curtails essential brain regeneration.
- Exercise. It increases the flow of blood, oxygen, and nutrients to your brain and can sharpen your thinking in minutes.
- Take proactive measures to reduce stress. Chronic stress often leads to brain fog and a variety of cognitive and mood disorders.
- Take a whole foods multivitamin supplement to fill in any nutritional gaps. This alone can improve brain performance.
- Take an omega-3 supplement. It’s widely agreed this is one of the best things you can do for both your overall health and your brain. (78)
- If you suspect you have an underlying medical condition, get a checkup and know for sure.
- If you have a medical condition, do what you can to get it under control.
- If you take any medications known to cause cognitive problems, talk to your doctor about switching or changing dosage. Discuss lifestyle changes that might minimize your need for medication.
Brain Fog: The Bottom Line
Brain fog is a catch-all phrase used to describe feelings of fuzzy thinking, mental confusion, and lack of focus.
Sometimes brain fog is caused by lifestyle factors like diet, stress, or lack of sleep and exercise.
Other times, it’s caused by an underlying health condition or as a side effect of a medication.
Be proactive about adopting a brain-healthy lifestyle and managing your health and medications.