What is COVID Brain Fog: Understanding and Managing this Long COVID Symptom

What is COVID Brain Fog: Understanding and Managing this Long COVID Symptom

One of the most perplexing and persisting issues faced by many who have suffered from COVID-19 is COVID brain fog. This condition presents a cluster of cognitive symptoms that significantly impact daily living.

From frontline health anecdotes to scientific studies, the phenomenon of brain fog in COVID-19 survivors is gaining recognition, prompting a deeper exploration into its nature, causes, and potential remedies.

Understanding COVID Brain Fog

COVID brain fog, a term that's been making rounds in the medical community, is a post-viral syndrome associated with the SARS-CoV-2 virus. It's a cognitive dysfunction that manifests as memory problems, difficulty concentrating, and a general feeling of being in a mental fog.

This condition is not exclusive to COVID-19, but the frequency and severity of brain fog in COVID-19 survivors have brought it to the forefront of post-viral syndromes.

Symptoms of COVID Brain Fog

  • Poor concentration

  • Memory lapses and forgetfulness

  • Slowed thinking and processing speed

  • Confusion or disorientation

  • Mental fatigue and exhaustion

  • Trouble finding words or articulating thoughts

  • Impaired decision-making and problem-solving abilities

These symptoms can vary in severity and duration, and not everyone with long COVID will experience all of them.

Other Long COVID Symptoms

  • Intense fatigue

  • Shortness of breath or difficulty breathing

  • Chest pain or tightness

  • Headaches

  • Loss of taste or smell

  • Difficulty sleeping

  • Dizziness or lightheadedness

  • Digestive issues such as nausea or diarrhea

  • Mood changes, including anxiety or depression

Causes of COVID Brain Fog

The exact causes of COVID brain fog are still under investigation, but several factors are believed to contribute to its development:


One of the leading hypotheses regarding the development of COVID brain fog involves neuroinflammation, a complex process characterized by the activation of immune cells and the release of inflammatory molecules within the central nervous system.

Scientific studies have demonstrated that SARS-CoV-2, the virus responsible for COVID-19, can directly invade the central nervous system by entering the brain through the bloodstream or via the olfactory nerve pathways. Once inside the brain, the virus may trigger an inflammatory response involving the activation of microglia, the resident immune cells of the central nervous system, as well as the infiltration of peripheral immune cells across the blood-brain barrier.

This can lead to the release of pro-inflammatory cytokines, chemokines, and other immune mediators, which can disrupt normal brain function and contribute to cognitive impairment. Furthermore, neuroinflammation can induce oxidative stress, disrupt neurotransmitter signaling, and impair synaptic plasticity, all of which are essential processes for maintaining cognitive function and memory.

Researchers have reported evidence of neuroinflammation in COVID-19 patients, including elevated levels of inflammatory markers in the cerebrospinal fluid, neuroimaging findings indicative of brain inflammation, and brain autopsies of critically ill COVID-19 patients revealing inflammatory changes in the brains.

Emerging research also indicates a possible link between COVID-19 and an increased risk of developing dementia. Dementia is a progressive neurological condition characterized by a decline in cognitive function, including memory loss, impaired reasoning, and difficulty with daily tasks. Excess inflammation is thought to be involved in the progression of dementia by causing nerve cell death.

The excess inflammation observed in COVID-19 patients, which is also thought to contribute to the progression of dementia, could shed light on brain fog. Brain fog, characterized by cognitive difficulties such as memory lapses, confusion, and impaired concentration, bears striking similarities to the cognitive decline seen in dementia. Thus, the inflammation associated with COVID-19 may contribute to the manifestation of brain fog symptoms.

Psychological Factors

Psychological factors associated with COVID-19, such as stress, anxiety, and depression, have been linked to brain fog symptoms. For example, van der Feltz-Cornelis et al. (2024) conducted a systematic review and meta-analysis of 17 studies (41,249 long COVID patients) and found that mental health conditions and brain fog both occurred in around one in five patients.

While the exact relationship between psychological factors of COVID-19 and brain fog is not known, what we do know is that prolonged activation of the stress response system can lead to structural changes in the brain, including atrophy of the hippocampus and prefrontal cortex, which are critical for memory and decision-making. These structural alterations, coupled with the cognitive effects of anxiety and depression, likely contribute to the manifestation of brain fog in individuals with long-term COVID.

Moreover, anxiety and depression can directly interfere with cognitive processes by causing rumination, intrusive thoughts, and difficulty concentrating. Studies have demonstrated that individuals with anxiety and depression often exhibit deficits in attention, working memory, and information processing speed, which are hallmark features of brain fog.

Managing COVID Brain Fog

Managing brain fog can be challenging, but several strategies may help alleviate its effects:

Lifestyle Changes

Eating a balanced diet rich in fruits, vegetables, whole grains, and lean proteins can provide your brain with the nutrients it needs to function optimally. Be sure to also drink plenty of water throughout the day to keep hydrated.

Getting enough quality sleep is crucial for cognitive function. Aim for 7-9 hours of sleep per night and try to maintain a consistent sleep schedule.

Regular exercise can also improve blood flow to the brain and promote the release of feel-good neurotransmitters like endorphins, which can help combat brain fog.

Medical Treatments

Cognitive behavioral therapy (CBT) can help manage the symptoms of brain fog by teaching you how to cope with cognitive difficulties. It's a structured program that helps you understand and change thought patterns leading to unwanted behaviors or feelings.


While lifestyle changes and medical treatments play significant roles, certain supplements may offer targeted support for cognitive function, mental clarity, and energy.

One notable supplement is NMN Bio's NAD+ Brain, which contains a combination of ingredients specifically formulated to enhance cognitive resilience, memory, focus, and overall cognitive processing.

The inclusion of L-Tyrosine in this supplement is particularly noteworthy, as it has been shown to enhance cognitive resilience during challenging situations, promoting mental clarity and focus. L-Tyrosine is an amino acid precursor to dopamine, a neurotransmitter associated with motivation, attention, and executive function.

Additionally, Citicholine is a key ingredient in the supplement. Citicholine is a naturally occurring compound that plays a crucial role in neurotransmitter production, including acetylcholine, a neurotransmitter involved in memory, focus, and cognitive processing.

Furthermore, the combination of L-Theanine and caffeine may help individuals maintain focus and attention while mitigating the negative side effects of caffeine, such as jitteriness and anxiety.

Finally, the incorporation of Fisetin and Apigenin in the NAD+ Brain blend decreases neuroinflammation, by blocking CD38, an inflammatory enzyme that is contributing to brain fog. The addition to these senolytic ingredients that are blood brain barrier permeable, along with Vitamin C that fights off oxidative stress, makes the NAD+ Brain an excellent supplement to fight off brain fog caused by COVID19.

Incorporating supplements like NMN Bio's NAD+ Brain into a comprehensive approach to managing COVID brain fog may provide targeted support for cognitive function, memory, focus, and overall mental clarity. However, it's essential to consult with a healthcare professional before starting any new supplement regimen, especially if you have underlying health conditions or are taking medication.

Navigating the Fog: A Summary

COVID brain fog presents significant cognitive challenges for individuals recovering from COVID-19, impacting memory, concentration, and overall brain health. While the exact mechanisms underlying this phenomenon are still being elucidated, evidence points to neuroinflammation and psychological factors as key contributors.

Managing COVID brain fog requires a multifaceted approach that addresses both the physical and psychological aspects of the condition. Lifestyle changes such as maintaining a healthy diet, getting enough sleep, and staying physically active can help reduce brain fog symptoms. Additionally, medical treatments, including cognitive behavioral therapy and targeted supplements, may provide relief for those struggling with persistent cognitive difficulties.

Researched and reviewed by Dr Elena Seranova, Ph.D.

Dr Seranova holds a master's degree in Translational Neuroscience from the University of Sheffield, UK, and a Ph.D in Stem Cell Biology and Autophagy from the University of Birmingham, UK. She is a published author in multiple peer-reviewed journals, including Cell Reports and Developmental Cell.


Agrawal et al. Brain autopsies of critically ill COVID-19 patients demonstrate heterogeneous profile of acute vascular injury, inflammation and age-linked chronic brain diseases. Acta Neuropathologica Communications. (2022)

Bremner, J. Traumatic stress: effects on the brain. Dialogues in Clinical Neuroscience. (2006)

Burks et al. Can SARS-CoV-2 infect the central nervous system via the olfactory bulb or the blood-brain barrier? Brain, Behavior, and Immunity. (2021)

Guasp et al. CSF Biomarkers in COVID-19 Associated Encephalopathy and Encephalitis Predict Long-Term Outcome. Frontiers in Immunology. (2022)

Katal, S., & Gholamrezanezhad, A. Neuroimaging findings in COVID-19: A narrative review. Neuroscience Letters. (2021)

Lee et al. A meta-analysis of cognitive deficits in first-episode Major Depressive Disorder. Journal of Affective Disorders. (2012)

Lyra et al. Inflammation at the crossroads of COVID-19, cognitive deficits and depression. Neuropharmacology. (2022)

van der Feltz-Cornelis et al. Prevalence of mental health conditions and brain fog in people with long COVID: A systematic review and meta-analysis. General Hospital Psychiatry. (2024)