The Essential Guide to Brain Fog: Symptoms, Causes, Treatments, and Natural Approaches

The symptoms and severity of brain fog vary from person to person.
The Essential Guide to Brain Fog: Symptoms, Causes, Treatments, and Natural Approaches
There are many conditions associated with brain fog, notably long COVID. (The Epoch Times)
Jacquelyn Waters

Do you feel like your thinking is fuzzy or scattered? Perhaps you feel you’re in a cloud or daze. If so, you may be dealing with brain fog.

While it is hard to define medically, brain fog is a relatable experience for many people.

In general, brain fog refers to problems associated with concentration, attention or focus, and memory. These problems can last for weeks, months, and sometimes years.

Brain fog is associated with many conditions, from autoimmune disorders to viral infections.

The condition has been a topic of particular interest recently due to its being a long-COVID symptom. Long COVID is diagnosed when COVID-19 symptoms persist beyond four weeks of the initial infection.

While brain fog can be frustrating, the good news is that researchers are beginning to understand the underlying factors that contribute to and exacerbate the condition, leading the way to possible treatment options.

Since brain fog does not have a formal definition in the medical community and there are no standard diagnostic criteria, estimating its prevalence is challenging. It is often more practical to estimate the prevalence of brain fog within the context of a specific condition.

What Conditions Are Associated With Brain Fog?

Brain fog is often considered more a symptom of other conditions than a condition in and of itself. The following are some of the conditions most closely associated with brain fog, and how their characterizations of brain fog differ.

Chronic Fatigue Syndrome

Patients with chronic fatigue syndrome (CFS) often describe their symptoms as exaggerated mental fatigue. Neurocognitive testing in CFS patients may reveal deficits in working memory, concentration, attention, and especially in the speed and efficiency of information processing.


About 15 percent to 40 percent of individuals suffering from chronic pain as a primary disorder experience brain fog.
Dr. Robert Keenan, vice chief for clinical affairs for the Rheumatology Division at Duke University, told Duke Health that well over 70 percent to 80 percent of patients with fibromyalgia experience brain fog.
Patients with fibromyalgia sometimes use the term “fibro fog” to describe the cognitive function deficits they experience with the condition. One meta-analysis involving 2,096 individuals found cognitive function was significantly decreased in fibromyalgia patients, with large effect sizes in learning/memory and attention/psychomotor speed. There was a medium effect size for executive function and working memory in these patients.


In cancer patients receiving treatment, up to 85 percent report mild to severe cognitive impairments.
Patients receiving cancer treatment often experience chemotherapy-induced cognitive impairment (CICI), commonly known as “chemo-brain.” These patients have difficulties with executive function, concentration, attention, and working memory.


About 70 percent of people with long COVID have cognitive complaints.
One study revealed that in adults with long COVID, those with self-reported brain fog had a higher frequency of word-finding difficulties and subjective memory impairment. In addition, their performance in computer-based cognitive tasks was poorer.

Systemic Mastocytosis

Systematic mastocytosis is a rare disorder resulting from a buildup of too many mast cells, a type of white blood cell. A review in Frontiers in Neuroscience mentioned that a recent survey of people with mast cell disorders reported that over "90% of them experienced moderate to severe brain 'fog' almost daily."

Postural Orthostatic Tachycardia Syndrome

Brain fog is a common complaint of those experiencing postural orthostatic tachycardia syndrome (POTS), a blood circulation disorder that causes a person's heart rate to increase when standing up and other symptoms to occur. Brain fog is most prominent in higher cognitive functions such as working memory and executive function, but is typically limited to when the individual is standing upright.

Celiac Disease

Most people with celiac disease report experiencing brain fog, though symptoms seem to improve with adherence to a strict gluten-free diet. More research needs to be done on the relationship between celiac disease and cognitive deficits, but current evidence further supports the idea that the gut and brain are intimately connected.

What Are the Symptoms of Brain Fog?

The symptoms and severity of brain fog vary from person to person. It is often difficult for patients to describe their cognitive deficits in concrete terms.
There may be some clinical overlap in the presence and severity of symptoms associated with brain fog, but in general, people report the following symptoms:
  • A feeling of mental fuzziness.
  • A feeling of being in a cloud.
  • Exaggerated mental fatigue.
  • Feeling "scattered."
  • Difficulties with concentration or attention.
  • Having trouble staying focused.
  • Difficulties with working memory.
  • Increased forgetfulness.
  • Difficulties processing information.

What Causes Brain Fog?

Scientists are still trying to understand what exactly causes brain fog, but according to the Frontiers in Neuroscience review, inflammation may be the primary cause. However, inflammation may have different triggers.

The Mechanism: Triggers of Neuroinflammation

The neuroinflammation that causes brain fog can have various triggers, including: Since certain chemotherapy agents are known to cause brain fog, insights from the mechanisms of how chemotherapy agents trigger brain fog are useful.
 While the exact cause of brain fog is unknown, inflammation is suspected to be the mechanism behind it. (The Epoch Times)
While the exact cause of brain fog is unknown, inflammation is suspected to be the mechanism behind it. (The Epoch Times)

Chemo-Induced Brain Fog

Authors of one research article state that chemotherapy agents are more toxic to brain cells than they are to cancerous cells, and these agents may trigger changes that result in neuroinflammation and brain aging.

The prefrontal cortex (PFC) is an area of the brain pivotal to planning, judgment, decision-making, and working memory—critical components in the discussion of clear thinking versus brain fog.

Researchers performed an interesting study in 2016 using mice and chemotherapy agents. They treated mice with mitomycin C (MMC), a chemotherapeutic shown to cause brain fog, and then analyzed gene expression and epigenetic changes in PFC tissues of the mice 24 hours and three weeks posttreatment.

Changes in gene expression were especially noticeable in the PFC tissues of female mice three weeks after the MCC treatment. Significantly, the researchers noted that most of the changes in the PFC tissues of female mice caused by MMC resembled changes that occur during the aging process and suggest that exposure to chemotherapy agents may speed up brain aging.

Further, the researchers stated that chemotherapy exposure triggers changes in DNA methylation, affecting how genes are expressed, and, thus, memory, cognitive regulation, and aging.

COVID-Induced Brain Fog

Much research has been done in the realm of neuroinflammation triggered by COVID-19.
A 2022 article in Oxford Open Immunology says that neuroinflammation is an event caused by an attack on the immune system. According to author Emma Kavanagh, “Activation of microglia in response to an immune system challenge can lead to a significant impact on cognitive processes, such as learning, memory and emotional regulation.”
Microglia are cells in the brain and spinal cord that function as the main form of active immune response in the central nervous system. When the brain is challenged by an immune system threat, microglia are activated, releasing cytokines as part of the inflammatory signaling process.

Typically the presence of cytokines and inflammation is short-term, as the brain tissue takes care of the immune system threat. However, if this activation becomes impaired, it can result in prolonged release of inflammatory cytokines.

While temporary cytokine presence in the brain can be beneficial, prolonged neuroinflammation negatively affects healthy cognitive processes.
Other studies confirm inflammation plays a crucial role in the pathology of mild cognitive impairment.

Who Is at Risk of Developing Brain Fog?

Anyone can develop brain fog, but those most at risk include the following:
  • Women: Females are more likely to develop long-COVID symptoms, including difficulties in cognitive ability. Menopause can also trigger brain fog. Women are also more likely to be affected by an autoimmune disease, a number of which have symptoms of brain fog.
  • People with poor nutrition.
  • People who aren't getting enough sleep or good-quality sleep.
  • People under a lot of stress.
  • Cancer patients being treated with chemotherapy drugs.
  • People with viral infections.
  • People with long COVID.
  • People with certain autoimmune disorders.
  • People with CFS.
  • People living with chronic pain.
  • People with depression.

How Is Brain Fog Diagnosed?

Brain fog is not a specific medical condition with formal criteria, so there is no standardized diagnostic test; however, your doctor can do several things to investigate the brain fog's cause.
  • Medical history and physical examination: Your doctor will take a detailed medical history that includes medications, stress levels, sleep patterns, and diet. In addition, he or she will perform a thorough physical examination.
  • Blood work: Your doctor may decide to run some labs to be sure you are not deficient in any nutrients and that your hormones, including thyroid hormones, are balanced. Lab work may also be done to test for any infections or other conditions that could cause brain fog.
  • Specialist evaluation: If warranted, your doctor may refer you to a specialist for a neurological evaluation, cognitive tests, brain imaging, or a sleep evaluation.

What Are the Treatments for Brain Fog?

Treatment depends on the cause of your brain fog and may include the following:
  • Diet and nutrition: Brain fog can be triggered by poor diet. It is valuable to assess the food you eat and make sure you are getting the nutrients you need.
  • Sleep improvement: Since poor sleep or lack of sleep can contribute to brain fog, address any sleep issues and make sure you are able to get quality sleep each night.
  • Stress management: Stress can be a causative factor in brain fog. If you have stress in your life, it would be beneficial to practice stress-reducing techniques.
  • Hormonal regulation: Sometimes hormone imbalances cause brain fog. Ensuring your hormones are properly balanced may be important in helping to alleviate brain fog.
  • Transcranial direct current stimulation (tDCS): This painless procedure delivers electric currents to parts of the brain and has been shown to improve attention in people with fibromyalgia.
  • Intravenous (IV) saline injection: In one study, 138 POTS patients self-reported various interventions to improve their brain fog. Sixty-six self-administered IV saline; 77 percent of them reported improvement.
There are no medications approved specifically for treating brain fog.

How Does Mindset Affect Brain Fog?

Stress can be a triggering or exacerbating factor (pdf) for many pathological conditions in the body, including cognitive deficits. Too much stress can cause structural changes in the brain, leading to memory disorders, and can decrease cognition—specifically affecting decision-making, attention, judgment, and learning.
The good news is that there are some straightforward ways to manage stress, which may make a significant difference in memory and cognition for those experiencing brain fog caused or exacerbated by stress.
  • Mindfulness: Mindfulness helps relax the body and create feelings of safety and peace.
  • Deep breathing exercises: Diaphragmatic breathing can decrease stress levels by calming the body.
  • Progressive muscle relaxation (PMR): This is a technique that involves tensing and then relaxing muscles in the body. It leads to decreased muscle tension and deep relaxation.
You may be limited in what you can do to alleviate symptoms. Be kind to yourself and try to do your best. Surround yourself with supportive friends and family who can help you through this period of difficulty with kindness and compassion. Realize you are not alone; there are many individuals struggling with brain fog. It is nothing to be ashamed of. If you need to, set alarms to remind yourself about important tasks and events, and write lists so you don’t forget anything.

What Are the Natural Approaches to Brain Fog?

There are numerous nutrients that affect cognitive function. Supplementing with the following nutrients may improve brain fog symptoms:

Omega-3 Fatty Acids

The three main omega-3 fatty acids are eicosapentaenoic acid (EPA), alpha-linolenic acid (ALA), and docosahexaenoic acid (DHA). In one study, EPA-rich supplements were given to participants before several assessments of cognitive function were performed, along with functional magnetic resonance imaging (MRI). Researchers found that participants’ brains worked “less hard” and attained “better cognitive performance” after EPA-rich supplementation as compared to prior supplementation.
Other studies revealed that omega-3 fatty acids lessen the severity of cognitive decline in older people and improve cognition after traumatic brain injury in rodents.
Omega-3 fatty acids can be found in fish like salmon, mackerel, and sardines, and in krill, flaxseeds, chia seeds, and walnuts.

Vitamin D

Vitamin D and its metabolites play an essential role in the central nervous system, particularly in the processes of neurogenesis, neuroplasticity, and neuroprotection. Studies show vitamin D reduces oxidative stress and helps induce neurotrophic factors and synaptic structural proteins. Low serum 25-hydroxyvitamin D has been connected to impairments in higher functioning associated with cognitive deficits.
Vitamin D can be found in fatty fish, eggs, mushrooms, milk, and fortified cereals.


  • Flavonoids: Flavonoids can be found in green tea, cocoa, Ginkgo biloba, red wine, and many other foods. In one study, the diets and cognitive health of 1,640 subjects 65 years or older were assessed over a period of 10 years. After 10 years, the subjects with the lowest intake of flavonoids lost, on average, 2.1 points on the Mini-Mental Status Examination, while those with the higher intake of flavonoids lost just 1.2 points, on average.
  • Lemon balm: In one study, drinking a liquid containing lemon balm was associated with increased working memory one hour and three hours after ingestion and improved mathematical processing one hour after ingestion.
  • Vitamin B12: Deficiencies in vitamin B12 can lead to cognitive deficits, including memory loss. Consider supplementing with B complex vitamins.
  • Vitamin C: Vitamin C deficiency has been linked to cognitive impairment.
  • Magnesium: Research suggests that suboptimal levels of magnesium in one's diet can lead to reduced cognitive function and brain fog symptoms. Magnesium is found in foods like legumes, nuts, green leafy vegetables, and dairy.

How Can I Prevent Brain Fog?

Brain fog is not always preventable; however, there are some things you can do to decrease the risks of developing it:
  • Practice good sleep hygiene: Making sure you are getting adequate sleep will decrease your chances of developing brain fog caused by poor sleep quality or lack of adequate sleep. Go to bed and wake up at the same time every day, get between seven and eight hours of sleep each night, and avoid screens around bedtime.
  • Eat a nutritional diet: Eating a nutrient-rich diet will decrease your chances of developing brain fog due to poor diet. Avoid inflammatory foods such as processed foods.
  • Manage stress: Chronic stress is a significant contributor to inflammation, which is a leading proponent of brain fog. Take breaks from tasks as needed, go outside, or socialize with a friend when you're feeling stressed.
  • Exercise regularly: Studies have shown that the parts of the brain that control thinking and memory are larger in people who exercise versus those who don't. Try to get 150 minutes of exercise weekly.
  • Practice mindfulness: Mind-body therapies such as yoga and meditation that encourage you to be mindful can help you stave off brain fog or clear instances of it.
  • Stay hydrated: Being dehydrated by as little as 2 percent can lead to disturbances in cognitive function. Drinking eight glasses of water a day is a good goal to strive for.
  • Address any underlying conditions: Since imbalanced hormones can cause brain fog sometimes, making sure your hormones are balanced can help prevent brain fog in some circumstances. A number of autoimmune and immune-mediated disorders are known to be associated with brain fog. Addressing the underlying medical condition may help prevent brain fog associated with these conditions.
Medically reviewed by Beverly Timerding, MD.
Jacquelyn Waters writes about health, science, and medicine. She has particular interest in all things neuroscience—from molecular neuroscience to psychology. She has 8 years of experience teaching college biology and received her Master’s degree in biomedical sciences with a specialization in neuroscience from Vanderbilt University.