Intense brain fog

5 Steps to Improve Brain Functioning

What is brain fog? Brain fog makes you feel unlike yourself, can affect your work and relationships, and can leave you feeling destabilized. Head over to our free quiz —which helps you connect the dots between your brain fog and your overall health—then read on to find out how to start feeling like yourself again.

Brain health is not only critical to mental capacity but is also paramount to emotional wellbeing. Your feelings and your thoughts are intimately connected and to feel good, you have to think good. At Parsley Health, we’re all about optimization, and we have many members that come to us looking for better mental focus, clarity, and brain power.

What does brain fog feel like?

Brain fog can show up in a variety of ways. Mostly it feels like your head contains cotton candy where there once was dense intellectual nervous tissue. The lights are on, but there’s nobody home.

You might be unable to concentrate for long enough—on work tasks, conversations, or even on the words you’re reading right now. You may have difficulty making up your mind, small decisions are a big deal, you need more coffee to focus, more snacks to stay awake, and more booze at night for temporary relief from the fog. In more severe cases, you might have headaches, problems with your vision or even nausea.

Brain fog causes: understanding how you are impacted

What causes brain fog? Brain fog can be a symptom of a nutrient deficiency, sleep disorder, bacterial overgrowth from overconsumption of sugar, depression, or even a thyroid condition. Other common brain fog causes include eating too much and too often, inactivity, not getting enough sleep, chronic stress, and a poor diet. These are some of the most common causes of brain fog that we see at Parsley Health.

Hormonal changes and mental fuzziness

Hormonal transitions are common throughout your life, whether during pregnancy, postpartum, menopause, or just unexpected changes in your environment and lifestyle. And oftentimes these periods leave your brain feeling fuzzy and confused—one study found that 60 percent of women have difficulty concentrating during menopause. In some cases, changing mood or sleeping habits could be contributing to your foggy head feelings, but it could also be due to the fluctuating hormone levels while your body tries to restore balance.

Impaired sleep

Poor sleep hygiene, like an irregular sleep and wake time, getting less than seven to eight hours of sleep a night, or blue light exposure before bed disrupts your natural circadian rhythm aka your internal body clock. This contributes to brain fog in a few different ways. In the case of blue light exposure close to bedtime, the blue wavelengths decrease the hormone melatonin that is essential for deep REM sleep. Both REM and non REM sleep is required to consolidate and process memories from the day. During the hours of 10pm and 2am is when your body and brain detoxify the most, so remaining in an active state during this time disrupts the body’s natural detoxification process and can contribute to fogginess.

An untimely wake time that doesn’t fall at the end of a sleep cycle can also impair your cognitive function and cause you to be more tired and foggy during the day. Apps like Sleep Cycle use your movement throughout the night to track what stage of sleep you’re in and sets an alarm to go off at the end of your sleep cycle, ensuring you won’t be disrupted mid deep sleep, as a conventional alarm clock tends to do. Note that hitting the snooze button once your alarm goes off won’t make you feel more rested, but instead increases the likelihood of you falling asleep, only to be disrupted again.

Diet deficiencies and food sensitivities

Vitamin B12 contributes to the formation of red blood cells and the maintenance of your central nervous system. It’s why a deficiency in B12 is sure to impair your energy levels and elicit an overall feeling of fatigue. A vitamin D deficiency can also be behind brain fog as decreased vitamin D levels are associated with impaired cognitive function. An unidentified food intolerance can also contribute to the foggy head feeling you’re experiencing. For example, gluten intolerance can lead to cognitive dysfunction via inflammatory pathways. Advanced blood work that looks at your nutrient levels as well as an elimination diet or food allergy or sensitivity testing can determine if any of these could be contributing to your brain fog.


Though stress may seem like a common and relatively harmless term, chronic stress can wreak havoc on your body. When your body perceives a stressful situation, it activates the sympathetic nervous system (SNS), or the fight-or-flight response. This response triggers the release of epinephrine, also known as adrenaline, and norepinephrine, and ultimately diverts energy away from your body’s typical functions and towards the stressor. This can make it difficult to think clearly, harder to focus, and could exhaust your brain. Learning to reduce your stress over time through interventions like meditation, exercise, or dietary changes, may help when your brain feels foggy.


Certain medications—both prescription and over the counter—are known to cause brain fog as a side effect. Though your head feeling cloudy while taking medication may be made out to seem normal and expected, it’s not. At Parsley Health , we believe in lifestyle interventions that solve your underlying issues before turning to medication. But if medication is necessary, your doctor can help you determine if your medication is compromising your brain health and work with you to find the right remedy—whether that’s changing medications or lowering your dosage.

Depression and anxiety

Depression and anxiety have been shown to impair cognitive function , affecting executive function, attention, and memory. Research suggests that this could be linked to either the loss of energy and motivation associated with mental health conditions, or physiological effects on the brain that make it difficult to function properly. If you struggle with depression or anxiety, talk to your healthcare provider about treatment options.

Thyroid disorders

Whether you feel tired all the time, lack focus and mental clarity, or deal with mood changes, a thyroid disorder may be at the root of your symptoms. This butterfly-shaped gland at the front of your neck is responsible for producing and releasing hormones that control everything from metabolism and heart rate to breathing and menstrual cycles and are frequently linked to brain fog. This is especially true with Hashimoto’s thyroiditis, an autoimmune immune disease where your immune system attacks your thyroid, inhibiting it from producing enough thyroid hormones and creating an inflammatory state. But whether your thyroid gland is producing too much thyroid hormone (hyperthyroidism) or too little thyroid hormone (hypothyroidism), this could be causing your brain fog. Other symptoms of a thyroid disorder can include weight loss or gain, fatigue, muscle weakness and digestive issues.

If you think a thyroid issue may be at play, talk to your doctor about a thyroid test . Many doctors will look at your TSH levels, but in reality there are other thyroid markers that can give a better picture of what’s going on. At Parsley Health , doctors routinely check Free T4, Total T4, Free T3, Reverse T3, anti-TPO antibodies, and anti-thyroglobulin to assess your thyroid health.

Heavy metal exposure

Heavy metals are everywhere in our daily lives—our food, beauty products, and even teeth fillings. The most common sources of heavy metal exposure are arsenic, mercury, aluminum, lead, thallium, and cesium. And while limited amounts of these metals won’t necessarily cause toxicity, heavy metal accumulation resulting from chronic exposure overtime can cause immune dysfunction, hormone imbalance, fatigue, brain fog, and high blood pressure. Testing levels of heavy metals in your blood is a good way to ensure your body is toxin-free, and regularly incorporating detox practices like heart-rate raising physical activity or weekly sauna sessions is a great start to keeping your levels under control and reducing any symptoms.

Brain fog treatment: How to get rid of brain fog

At Parsley Health, we work with our members to get to the root cause of their issues and resolve brain fog for good. As part of your brain fog treatment, your doctor will work with you to understand your complete health history, symptoms, and then order the appropriate lab work to test things like your thyroid function and heavy metal levels. With this information, your doctor can craft a personalized health plan to address your brain fog and any other symptoms you may be experiencing. These are a few recommendations our doctors and health coaches may have to help you get rid of brain fog.

1. Give your digestive system a rest.

Intermittent fasting is all the rage in the nutrition and weight loss world. But it’s not just beneficial for dropping pounds, calorie restriction and longer periods between meals can also promote neurological health and decrease neurodegenerative diseases . To treat your brain fog and gain back some mental clarity, start with trying to extend the time between the last meal of the day and the first meal of the next day. Shoot for 12 hours. This promotes a process called ketogenesis, which can stimulate brain regeneration. But ketogenesis can be tricky and should be practiced under the guidance of someone who knows what they’re doing. Work with a Parsley Health doctor and coach to leverage both the timing and contents of your meals for better mental focus.

2. Move it or lose it.

Neurodegenerative disorders such as Alzheimer’s dementia and even mild cognitive dysfunction are more prevalent in sedentary populations. Increased activity levels are clearly associated with sharper mental acuity , a better memory and an elevated mood. Exercise causes the release of helpful chemical messengers called cytokines as well as chemicals that are responsible for elation called endorphins. These chemicals bathe and rejuvenate the brain. Try to engage in some type of enjoyable movement every day. Walk, run or dance. Whatever floats your boat will surely also float your mood.

3. Be an efficient sleeper.

The classic mistake people make with their brains, whether it’s dealing with work, school or whatever looming project deadline, is that they try to maximize their time by staying up late and/or getting up early. This typically backfires because cognitive abilities decrease with sleep deprivation. Sleep at least seven hours nightly, preferably eight or even nine when possible. The quality of your work will increase while the time it takes to produce such quality work will diminish.

4. Balance active workouts with active tune-ins.

Many types of exercise stimulate the sympathetic nervous system which is responsible for “fight or flight” responses. Unfortunately, your body doesn’t know the difference between running on a treadmill or running from danger—both look like stress. Stress manifests as brain fog. In order to reduce stress, you need to flex your parasympathetic nervous system, which is engaged during rest and relaxation and helps to calm your body and your mind. You can do this by incorporating more meditation and yoga into your routine.

5. Feed your brain.

Your brain is made up of a lot of fat and protein. Does it make sense that our diets are low in both of these food groups? Not so much. Sugary processed stuff is not your brain’s fave food. Stick to plant-based Paleo (mostly vegetables, enough protein, and always some good fats). Get plenty of omega-3 fatty acids (for their anti-inflammatory powers), a lot of antioxidants and coenzyme Q10 (essential for energy), and boost your body’s natural energy production and regeneration with essential vitamins and minerals.

Brain Fog: 6 Potential Causes

Brain Fog: 6 Potential Causes

Medically reviewed by Debra Rose Wilson, Ph.D., MSN, R.N., IBCLC, AHN-BC, CHT — By Valencia Higuera — Updated on April 29, 2022

Brain fog is a symptom that can be caused by stress, sleep changes, medications, and other factors. It can cause confusion, memory issues, and a lack of focus.

Brain fog itself is not a medical condition but instead a symptom of other medical conditions. It’s a type of cognitive dysfunction involving:

  • memory problems
  • a lack of mental clarity
  • poor concentration
  • an inability to focus

Some people also describe it as mental fatigue. Depending on the severity of brain fog, it can interfere with work or school. But it does not have to be a permanent fixture in your life.

There are several explanations for why brain fog happens. Once you identify the underlying cause, you can begin fixing the problem. Here are six possible causes.

1. Stress

Chronic stress can increase blood pressure, weaken the immune system, and trigger depression, according to 2017 research. It can also cause mental fatigue.

When your brain is exhausted, it becomes harder to think, reason, and focus.

2. Lack of sleep

Poor sleep quality can interfere with how well your brain functions, according to 2021 research. Aim for 8 to 9 hours of sleep per night.

Sleeping too little can lead to poor concentration and cloudy thoughts.

3. Hormonal changes

Hormonal changes can also trigger brain fog, according to 2018 research. Levels of the hormones progesterone and estrogen increase during pregnancy. This change can affect memory and cause short-term cognitive impairment.

Similarly, a drop in estrogen levels during menopause can cause forgetfulness, poor concentration, and cloudy thinking, according to 2019 research.

4. Diet

Diet can also play a role in brain fog. Vitamin B12 supports healthy brain function, and a vitamin B12 deficiency can bring about brain fog, according to a 2021 research review.

If you have food allergies or sensitivities, brain fog may develop after eating certain foods. These include:

  • aspartame
  • peanuts
  • dairy

Removing trigger foods from your diet may improve symptoms.

5. Medications

If you notice brain fog while taking medication, talk with your doctor. Brain fog may be a known side effect of these medications, according to 2021 research. Lowering your dosage or switching to another drug may improve your symptoms.

Brain fog can also occur after cancer treatments. This is referred to as chemo brain.

6. Medical conditions

Medical conditions associated with inflammation, fatigue, or changes in blood glucose level can also cause mental fatigue. For example, brain fog is a symptom of chronic fatigue syndrome, which involves persistent fatigue for a prolonged period of time, according to 2020 research.

People who have fibromyalgia may experience similar fogginess on a daily basis, according to a 2015 research review.

Other conditions that may cause brain fog include:

  • anemia
  • depression
  • diabetes
  • Sjögren syndrome
  • migraine
  • Alzheimer’s disease
  • hypothyroidism
  • autoimmune diseases, like lupus, arthritis, and multiple sclerosis
  • dehydration
  • viral infections, like COVID-19

Talk with a doctor if you have a persistent lack of clarity that worsens or does not improve.

A single test cannot be used by a doctor diagnose brain fog. Brain fog may signal an underlying issue, so a doctor will conduct a physical examination and ask about your:

  • mental health
  • diet
  • level of physical activity
  • current medications or supplements

You should let your doctor know about other symptoms you might have. For example, someone with hypothyroidism may have brain fog along with hair loss, dry skin, weight gain, or brittle nails.

Blood work can help your doctor identify the cause of brain fog. A blood test can detect the following:

  • irregular glucose levels
  • poor liver, kidney, and thyroid function
  • nutritional deficiencies
  • infections
  • inflammatory diseases

Based on the results, your doctor will determine whether to investigate further. Other diagnostic tools may include imaging tests to look inside the body, like X-rays, magnetic resonance imaging (MRI), or computerized tomography (CT) scans.

The doctor may also conduct allergy testing or a sleep study to check for a sleep disorder.

Keeping a food journal can help you determine if your diet contributes to brain fog.

Brain fog treatment depends on the cause. For example, if you’re anemic, iron supplements may increase your production of red blood cells and reduce your brain fog.

If you’re diagnosed with an autoimmune disease, a doctor may recommend a corticosteroid or other medication to reduce inflammation or suppress the immune system.

Sometimes, relieving brain fog is a matter of correcting a nutritional deficiency, switching medications, or improving the quality of your sleep.

Home remedies to improve brain fog include:

  • sleeping 8 to 9 hours per night
  • managing stress by knowing your limitations and avoiding excessive alcohol and caffeine
  • exercising
  • strengthening your thinking abilities (try volunteering or solving brain puzzles)
  • finding enjoyable activities
  • increasing your intake of protein, fruits, vegetables, and healthy fats

Brain fog can be frustrating, but relief is possible. You should not ignore your symptoms because if left untreated, brain fog can impact the quality of your life. Once the underlying cause is addressed, your mental clarity can improve.

Last medically reviewed on April 29, 2022

How we reviewed this article:

Healthline has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations. We avoid using tertiary references. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.

  • Ali SA, et al. (2018). Hormonal influences on cognitive function.
  • Brain fog. (n.d.).
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  • Eide S, et al. (2020). Doxorubicin chemotherapy-induced "chemo-brain": Meta-analysis.
  • Fibro fog. (n.d.).
  • Gava G, et al. (2019). Cognition, mood and sleep in menopausal transition: The role of menopause hormone therapy.
  • Hanson JA, et al. (2021). Sleep deprivation.
  • Kravitz HM, et al. (2015). Fibrofog and fibromyalgia: A narrative review and implications for clinical practice.
  • Mackay M. (2015). Lupus brain fog: A biologic perspective on cognitive impairment,
    depression, and fatigue in systemic lupus erythematosus. DOI:
  • Markun S, et al. (2021). Effects of vitamin B12 supplementation on cognitive function, depressive symptoms, and fatigue: A systematic review, meta-analysis, and meta-regression.
  • Sandler CX, et al. (2020). Chronic fatigue syndrome: progress and possibilities.
  • Yaribeygi H, et al. (2016). The impact of stress on body function: A review.
  • Zhou L, et al. (2019). Food allergy induces alteration in brain inflammatory status and cognitive impairments.

Our experts continually monitor the health and wellness space, and we update our articles when new information becomes available.

Current Version

Apr 29, 2022

Written By

Valencia Higuera

Edited By

Shannon Ullman

Medically Reviewed By

Debra Rose Wilson, PhD, MSN, RN, IBCLC, AHN-BC, CHT

Copy Edited By

Ahmed Fara

May 23, 2018

Written By

Valencia Higuera

Edited By

Christina Nagatani


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Medically reviewed by Debra Rose Wilson, Ph.D., MSN, R.N., IBCLC, AHN-BC, CHT — By Valencia Higuera — Updated on April 29, 2022

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How doctors look for ways to treat protracted covid – DW – 30.06.2022

Brain fog can be as impenetrable as its counterpart in nature Photo: Moritz Frankenberg/dpa/picture alliance


Gudrun Heise | Viktor Weitz

June 30, 2022

Brain fog is characterized by lethargy and lack of clarity in thinking. Often it is a consequence of a coronavirus infection.


It is usually difficult for patients to describe in words the state they experience with so-called "brain fog". The symptoms are not yet fully understood, so it is often difficult for doctors to make an accurate diagnosis. And it is difficult for patients suffering from this disease to describe its symptoms. They are just in a foggy state.

In addition to problems with concentration, difficulty in finding words and forgetfulness, patients experience other symptoms that are characterized by general mental exhaustion. These symptoms develop not only in the elderly, but also in young people, especially as a result of their illness with COVID-19..

Since the beginning of the coronavirus pandemic, many hospital neurological departments and medical institutions have recorded an increase in the number of patients with brain fog symptoms. Many even have trouble with memory or simple day-to-day tasks. According to experts, "brain fog" is a serious condition that can significantly impair brain function. Research on whether brain fog causes structural damage to the brain, or whether inflammatory processes in the brain may play a role, has not yet been confirmed. To find out, patients' brains are examined using MRI. Scientists and doctors suggest that "brain fog" is reversible and may disappear on its own. But this can take a long time - from several months to one year.

Accidental discovery

A few years ago, the German startup Berlin Cures developed BC 007 to treat severe heart conditions. Today it is in the second stage of research. Doctors have high hopes for it, in addition, it can help in the treatment of post-covid conditions. Bettina Hohberger used BC 007 in the ophthalmology department of the Erlangen University Hospital in a patient with glaucoma. The specialists were able to detect specific autoantibodies in the patient's blood and diagnose circulatory disorders in the eyes. Intended for the treatment of severe cardiovascular diseases, BC 007 may also improve blood circulation in other organs.

"Patients with post-COVID syndrome can also have circulatory problems," suggests Bettina Hochberger. BC 007 is able to neutralize autoantibodies and improve blood circulation in the patient's body.

First results exceeded all expectations

"We did not expect the drug to have such an effect. Our first patient had glaucoma and post-covid syndrome, and then we had three more patients with long-term post-covid syndrome. All patients after treatment with the new the drug improved thinking ability and concentration," says doctor Bettina Hochberger.

Fatigue and extreme exhaustion are symptoms of "brain fog" Photo: ROBIN UTRECHT/picture alliance

"If BC 007 works, it should be available to everyone who needs it," says the doctor. According to startup Berlin Cures, it is planning a major international study that aims to accelerate the approval of the drug BC 007 for the treatment of post-COVID syndrome.

"Brain fog" develops not only with prolonged covid, it is often a sign of various brain dysfunctions. Accordingly, treatment options and prognosis are highly individual and complex.

A holistic approach is needed

Scientists and doctors advise those suffering from brain fog to be as active and alert as possible, and to listen to signals from their bodies. A healthy diet, exercise and good sleep are important. Another recommendation is to reduce or completely eliminate alcohol consumption, as it can affect brain function and thinking abilities.

Various medications that people with brain fog may take should also be checked for side effects. And finally, the body and brain need a sufficient amount of fluid, because it is important for all the functions of our body. All this can help in overcoming the disease and regaining the ability to see familiar things a little more clearly again.

"People who suffer from so-called brain fog and want to regain their ability to think clearly and see the world with the same eyes, it's safe to say that doctors and scientists are working to find an effective treatment," emphasizes doctor Bettina Hochberger. "The cure won't be available tomorrow, but there are glimmers of hope. So don't get discouraged and don't give up."

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what it is and why it happens

Persistent poor concentration, memory problems, and lack of mental clarity can indicate serious health problems.

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Brain fog is not a disease in itself, but rather a symptom of other diseases. This is a type of cognitive dysfunction that includes memory problems, lack of mental clarity, poor concentration, and an inability to focus. Some people also describe it as mental fatigue. Depending on the severity of the brain fog, it can interfere with work or study. But it doesn't have to be a permanent feature of your life.

Contents of the article

There are many explanations for why brain fog occurs. Once you determine the root cause, you can begin to eliminate it. Here are six possible reasons.


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Chronic stress can raise blood pressure, weaken the immune system, and cause depression. It can also cause mental fatigue. When the brain is depleted, it becomes harder to think, reason, and focus.

Lack of sleep

Poor sleep quality can also affect brain function. Try to sleep eight to nine hours a day. Lack of sleep can lead to poor concentration and foggy thoughts.

Diet can also contribute to brain fog.

Learn more