What is Brain Fog?

Brain fog is a phrase that describes feelings of confusion, forgetfulness, lack of focus and mental clarity. While a significant problem on its own, brain fog is also a sign of underlying health conditions. If you feel foggy, unfocused, and like you just can't think, your brain is sending a signal that there's an imbalance in your life that needs to be addressed.

Brain fog can be the result of a wide range of health conditions, including but not limited to, stress, dietary and food sensitivities, chemotherapy, hypothyroidism, depression, anxiety, and insomnia. In other words, if you're experiencing brain fog, it doesn't mean you have any particular condition. Rather, it's a check engine light for your overall health and wellness.

Brain fog does not have to be a life sentence. Once the root cause is discovered, adjustments in lifestyle, diet, medications, and stress management can lift the fog and restore clarity, focus, and energy. The fog lifts.

Symptoms of brain fog

The symptoms of brain fog include difficulty thinking, focusing, or performing cognitive tasks. Word recall problems, short-term memory impairment, and losing your train of thought can often leave you feeling frustrated or even hopeless. This sense of being lost in the fog often causes additional stress, which only amplifies brain fog.

Additional symptoms of brain fog include:

- low energy or fatigue (including chronic fatigue syndrome)

- irritability

- trouble concentrating, feeling easily distracted

- headaches

- forgetfulness and trouble remembering information

- difficulty communicating

- low motivation, feeling hopeless or mildly depressed

- anxiety

- confusion

- trouble sleeping through the night or insomnia

- difficulty exercising and performing daily activities

"I've noticed that people who report brain fog usually don't show it on the outside," says acupuncturist Jennifer Leonard. "They manage to mask their difficulty finding words or remembering names. Easy tasks may take twice as long as they did previously. Their families and colleagues often don't notice, but it's very distressing to them on the inside. They don't feel like themselves. They're afraid to admit this. They don't want to be judged or thought incompetent. They may fear that they are experiencing early signs of Alzheimer's or dementia - when it may have a wide array of treatable causes."

Brain basics 101: How does the brain work?

It's easier to understand brain fog if you understand some important basic factors of brain functioning. These include:

- Energy

The brain uses more energy than any other organ, accounting for up to 20% of the body's total energy consumption. Glucose derived from our diet provides brain fuel. Poor dietary choices or poor management of blood sugar levels may affect proper brain functioning.

- Healthy fat

The brain is about 60% fat and the quality of this fat reflects the fats contained in our diet. The fat insulates neurons, protecting and preventing them from becoming over-excitable, similar to the covering insulating the electrical wire to your lamp. Healthy fats in the diet are correlated to the prevention of brain diseases like Alzheimer's and Parkinson's. Poor quality fats in the diet are tied to increased inflammation, cognitive decline and increased progression of brain-based diseases.

- The Blood-Brain Barrier

The Blood Brain Barrier is an important gatekeeper, a semi-permeable membrane. It allows materials needed for survival such as glucose and oxygen to cross into the brain and excludes toxic materials. This barrier also contains the neurotransmitters responsible for creating thoughts, emotions, and understanding. IF the barrier is damaged - by autoimmune disorders, chronic inflammation, head trauma, stress or environmental toxins, for example - elements from our blood such as proteins and medications may pass through and into the delicate bubble of the brain's environment.

- Sleep

During deep sleep cycles, our brain is able to clean out metabolic waste, consolidate memories and break down connections that are no longer needed. Inadequate sleep impairs our ability to learn or remember information as well as allows for the buildup of metabolic wastes.

What are the causes of brain fog?

Brain fog can be the result of a wide array of causes. Among others, these can include underlying medical conditions, medication, diet and nutrition, and stress or mental-health-related factors.

Physical causes

In many cases, brain fog is the result of a larger problem going on in your body, what you put into your body, or both.

Hormonal imbalances

Hormonal imbalances are a leading cause of brain fog - especially reduced estrogen in the peri- or postmenopausal time which can cause brain fog as there are estrogen receptors in the brain that are involved in cognition. Also, lowered production of the thyroid hormone, known as hypothyroidism, leads many people to experience a decline in their mental sharpness, including difficulty concentrating, short-term memory loss, mood disturbances, and cognitive impairment.

Gut health

There is also a strong connection between gut health and brain health. If you have leaky gut syndrome or any inflammation of the gut, this can lead to symptoms of brain fog. As autoimmune disorders are closely linked to gut health as well, they are often accompanied by brain fog.


Individuals suffering from stress-related conditions such as fibromyalgia are no stranger to brain fog. In these cases, it is sometimes dubbed "fibro fog". Patients display classic brain fog symptoms and oftentimes report those symptoms to be just as, or even more, challenging than their physical pain.


The term "chemo brain" is used to express the particular presentation of brain fog in cancer patients going through chemotherapy treatments. "Chemo brain" is thought to be caused by a combination of the disease itself, treatments, sleep problems, hormonal changes, depression, and stress.

Additional conditions and concerns

Additional conditions known to cause brain fog include: ADHD, adrenal fatigue, anxiety, brain injuries, chronic pain, depression, diabetes, heavy metal toxicity, hepatitis C, hypoglycemia, irritable bowel syndrome, Lyme disease, menopause, multiple sclerosis, neurodegenerative disorders, neurotransmitter imbalance, rheumatoid arthritis, seasonal allergies, and substance abuse or withdrawal.

The role of medication in causing brain fog

Prescription medications, as well as over-the-counter medications, often lead to brain fog. These include many common medications. Cholesterol-lowering statins and sleeping pills are major contributors to brain fog symptoms, especially memory loss. An entire class of drugs known as anticholinergics work by blocking the action of acetylcholine, the brain chemical of memory and learning. Typical side effects of anticholinergic drugs include brain fog, forgetfulness, and inability to concentrate.

Additional medications that contribute to brain fog can include:

- Lithium

- Mood stabilizers

- Narcotic painkillers

- Sleeping pills

- Benzodiazepines

- Blood pressure medication

- Quinidine

- Long-term use of stimulants such as Adderall

-  Naproxen

- Steroids

- Antibiotics (quinolones)

- Antihistamines

- Tricyclic antidepressants

- Interferons

- Insulin

- Beta-blockers

- Antipsychotics

- Methyldopa

- Barbiturates

- Chemotherapy drugs

- Parkinson's medication - scopolamine, atropine, glycopyrrolate

- Epilepsy medication - phenytoin or Dilantin

Dietary causes of brain fog

What you eat plays a major role in brain fog. There is a strong connection between gut health and brain health, and anything that goes through your gut quickly affects your brain. Sugar, artificial sweeteners, and other foods like gluten, dairy, and many vegetable oils, often lead to inflammation in the gut, including contributing to conditions like leaky gut syndrome or autoimmune disorders. These all often result in brain fog.

Sugar and other sweeteners like high fructose corn syrup also wreak havoc with your blood sugar. Eating many sweeteners causes your blood sugar (glucose) levels to spike, then crash. This can lead to brain fog, mood swings, irritability, tiredness, mental confusion, and impaired judgment. Low glucose levels can also throw your body into fight, flight, or freeze mode, producing high amounts of the stress hormone cortisol. This makes thinking clearly even more difficult.

Additional dietary causes of brain fog include:

- Low-fat diets. The brain needs healthy fat in order to function properly. A low-fat diet essentially starves the brain of vital fuel.

- Food additives like MSG, and artificial sweeteners like aspartame and sucralose (among others). These substances are often highly toxic, and can cause significant health problems, including neurological symptoms.

- Dehydration. While drinking enough water seems like common sense, 75% of Americans are thought to be chronically dehydrated. Even mild dehydration affects your ability to think clearly. It takes only 2% dehydration to impact your attention, memory and other cognitive skills.

Nutritional deficiencies

Even if you consume a healthy diet and avoid the harmful foods and substances mentioned above, you may still experience brain fog. This could be because your body is still missing out on vital nutrients that your brain needs in order to function properly. These include vitamin B12, vitamin D, and omega 3 fatty acids. Vegetarians and vegans are often B12 deficient, while people who live further from the equator or spend a great deal of time inside usually don't get enough vitamin D. A doctor can test the levels of important nutrients in your body.

Physical inactivity

Physical activity has an important influence on brain health. The symptoms of brain fog and other underlying conditions may inhibit your motivation to exercise. However, exercise increases the production of endorphins - a feel-good neurochemical with natural pain relieving properties. It also increases the flow of glucose and oxygen to the brain. Additionally, exercise burns off the stress hormone cortisol and contributes to new brain cell formulation. Without regular exercise, your brain doesn't experience these beneficial effects, which can keep brain fog from lifting.

On the flip side, over-exercising can lead to fatigue and low blood sugar, which may in turn cause brain fog.


Many of the underlying conditions that can cause brain fog have genetic components to them. However, brain fog itself is also linked to the MTHFR gene - Methylenetetrahydrofolate reductase, an enzyme that affects how the body absorbs folic acid, or vitamin B9, a nutrient which is essential for brain health. People with a mutation in their MTHFR gene are not able to properly process folic acid, depriving their brains of vital nutrition. If you're experiencing brain fog, you can have your MTHFR gene tested for the mutation.

Emotional causes

Emotional turmoil, trauma, grief, heartbreak or stress of any kind can contribute significantly to brain fog. In other words, the more stressed out you're feeling, whether by anything in particular or by your general life circumstances, the more difficult it can be to think. Painful emotions and stress can put a great deal of strain on your whole body. They can preoccupy your thoughts, and even activate your body's fight, flight or freeze system, which shuts down parts of your rational brain, making clear thinking very difficult. Seeking emotional support such as therapy or counseling can be a very effective way to relieve brain fog in some situations.

Brain fog, anxiety and depression

In particular, brain fog is often linked with anxiety and depression. While anxiety is a common symptom of brain fog, episodes of anxiety and exacerbated stress or nervousness can also often lead to brain fog. Depression also often produces feelings of brain fog, which can then contribute to a sense of low self-worth or hopelessness.

The brain fog-mental health relationship can be a vicious cycle. Chronic stress and anxiety can lock your body into a state of overproducing the stress hormone cortisol. High levels of cortisol can contribute to symptoms of brain fog. But as your brain fog gets worse, you can start to feel even more anxious or stressed, leading your body to produce yet more cortisol. Finding ways to lower overall stress can be key to treating brain fog.

Sleep patterns

Sleep deprivation and sleeping disorders are a big factor of brain fog. Even one poor night of sleep can affect your memory, concentration, coordination, mood, and judgment. Lack of sleep can also increase your overall stress levels.

Environmental causes

Exposure to toxic chemicals in the environment or in your home can also put tremendous strain on the brain, leading to symptoms of brain fog. If you can, make an effort to ensure your home is free from toxins, which can include cleaning chemicals, furniture coated in fire-retardant chemicals, mold, and pesticides. Eating organic can help limit your exposure as well.

How to heal brain fog

You can heal from brain fog, however, identifying the root cause (or causes) is essential. Fortunately, whether the cause is due to diet, nutrient deficiency, stress, sleep disorders, underlying health conditions or medication side effects, it is possible to work with.

Jennifer Leonard suggests her patients see what they can take off their plates to help ease the stress or pressure of brain fog. "I ask if they can hand over financial tasks to their partner for now, or start using an electronic grocery list so they don't have to keep it all in their heads. Minimizing cognitive tasks and focusing only on what they absolutely have to do can provide relief while we sort out what's going on and what we can do to help."


If you are experiencing symptoms of brain fog, a good first step is to figure out what may be causing them. A holistic physician can help you explore the many possible causes, and narrow them down based on your life history, individual symptoms, and results of lab tests, among other measures. This is a good way to identify anything from food sensitivities to gut problems to the MTHFR mutation.

Checking for symptoms of brain fog after eating can be an important assessment tool as well. If you notice that your brain fog worsens after you eat certain foods, take note of that. That food is probably part of the problem. Conversely, if you notice some foods make you feel more clear-headed - that food can probably help.

In addition to identifying and addressing underlying health conditions, it is also important to look at which prescription and over-the-counter medications you are taking. Talking to your doctor about your symptoms of brain fog, as it relates to your current medications, is a great way to begin.


Stress, painful emotions, difficult relationships or other lifestyle factors can all cause or contribute to brain fog. If you're experiencing brain fog, it can be a good idea to explore what in your life circumstances could be causing you significant stress, or other emotional turmoil. As with many health problems, finding ways to lower your stress levels, relax, and find greater peace can be a key part of healing.

Relaxation techniques can include exercise, yoga, meditation, deep breathing, walking, music - anything that can help ground you in your body. Making changes to how you live your life: finding ways to reduce stress at work, or even changing jobs; spending more time with friends; giving back to the community - all these can help you feel greater ease and lower the strain on your brain.


If food and nutrition are major contributors to causing brain fog, they are also a major part of the solution.


To address dietary causes of brain fog, many nutritionists recommend that you eat a diet rich in fat from healthy sources like nuts, avocados, coconut oil, olive oil, fatty fish like wild salmon, eggs, and grass-fed meat. Avoid vegetable oils like sunflower, safflower or canola oil. Vegetable oils are high in pro-inflammatory omega-6 fatty acids which contribute to brain inflammation. Chronic brain inflammation can be an underlying cause of brain fog, ADHD, anxiety, depression, and memory loss, as well as serious neurological diseases such as stroke and Alzheimer's.

Eating whole, fresh foods is optimal. This means lots of dark, leafy greens, lean proteins, and if possible, nothing from a box. This goes hand in hand with reading food labels and avoiding food additives as well as artificial sweeteners.

Along with eliminating food additives, brain fog can also be lifted by identifying food allergies and sensitivities. If you suspect an allergy or sensitivity, going on a trial elimination diet is a way to intuitively discover which types of foods aren't working for you. A basic elimination diet means cutting suspect foods out of your diet for a while and observing how you feel. It is always a good idea to reflect upon your food choices and ask yourself if they are likely to make your body feel good and energized.

Supplements for treating brain fog

Many vitamins and herbal supplements can help treat brain fog or support your brain health. Your qualified holistic health professional may suggest some of the following:

- Vitamin B12 - aids brain function and plays a crucial role in memory and focus

- Vitamin D - helps clear brain fog, lifts depression, improves clarity and memory

- Magnesium - relaxes the central nervous system, blocks stress hormones, helps migraines

- Probiotics - improve gut health by creating healthy bacteria.

- Omega-3 essential fatty acids - combats fatigue, poor memory, mood swings and depression

- Curcumin - boosts memory and attention, decreases inflammation, helps treat depression

- Rhodelia - eliminates fog and increases focus

- Bacopa - improves memory and cognitive function, reduces stress and anxiety, helps with symptoms of ADHD

- Gotu kola - treats mental fatigue, anxiety, depression, memory loss, and insomnia

- Coenzyme Q10 (CoQ10) - fuels your cells' mitochondria to boost brain power.

Healing modalities

An appointment with a functional medicine, integrative medicine, naturopathic or other holistic physician is a good way to start healing your brain fog, as they can assess and treat hormonal imbalances. As diet is likely part of the problem, a nutritionist or dietician can help you get your eating on track to support your gut and brain health. Acupuncturists, chiropractors, and occupational therapists can help with stress reduction, and mental health professionals like counselors or therapists can help with psycho-emotional healing which may also play a role.

The following experts reviewed and contributed to this article:

Andrew Wong, MD, Functional Medicine Doctor and Medical Acupuncturist


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