Post-COVID Brain Fog Is Real: How To Get Your Clarity Back

I’ll start this one off with a statistic: more than 80% of individuals with long COVID experience brain fog as a symptom. (1) Whether or not you are dealing with other post-COVID symptoms, lingering brain fog is very common and I know just how disruptive it can be. 

So why does post-COVID brain fog happen, and how can you restore your mental clarity, cognitive function, and concentration holistically? That’s what I’m going to break down for you today. 

What Is COVID Brain Fog? 

Brain fog is one of the most common symptoms of long COVID. Sometimes it starts during the active virus and continues for months afterwards, and other times brain fog doesn’t emerge until a few months after infection. 

If you’ve ever experienced brain fog, you know that it can be hard to describe or pinpoint. There is no universal definition of brain fog and it likely feels a bit different for everyone. It can be thought of here as a general term to describe cognitive issues including mental fatigue, fuzzy thinking, forgetfulness or memory loss, difficulty focusing, and lack of mental clarity. 

Brain fog may come and go or feel constant. To be characterized as a symptom of long COVID, it has to be present three months after a COVID-19 infection, and to continue for at least two months. (Many people also experience brain fog as a symptom of other conditions). 

Post-COVID brain fog is often accompanied by other persistent symptoms including general fatigue, headaches, mental health issues such as anxiety, or digestive symptoms. We also see a lot of overlap with dysautonomic symptoms and conditions including lightheadedness, dizziness, or POTS. 

What Causes Post-COVID Brain Fog? 

The question of what causes post-COVID brain fog is multilayered. Knowing that the majority of people with long COVID experience brain fog as a symptom, researchers are exploring the possible mechanisms behind this, including the recent observation of increased AMPA receptor density among long haul patients with cognitive impairments. (1) 

Long COVID patients have been shown to have dysregulation of the blood-brain barrier. (2) COVID can also live on in the gut after an acute SARS-CoV2 infection, which can trigger cognitive issues via the gut-brain axis. And there are several other theories behind how COVID can affect the brain, including by directly causing neuroinflammation. (3) 

Recognizing Underlying Imbalances

There’s another big question that requires us to take a step back. Instead of just asking why brain fog occurs among people with long COVID, we need to ask ourselves why long COVID happens in the first place. 

While surprisingly common, not everyone who gets COVID develops long COVID. Some people get the virus and recover within a week, while others experience delayed and prolonged symptoms (like brain fog) for months or even years. So what is causing this more extreme reaction for certain people? 

In most cases in our telehealth functional medicine center, what we find when we dig into this question is an underlying imbalance that started before they got the COVID virus, with the viral infection pushing their systems over the edge into dysfunction and chronic symptoms. COVID can also “unmask” pre-existing conditions that hadn’t yet been detected or diagnosed. 

This is the same thing we’ve seen happen with outsized reactions to other viral infections, such as Epstein-Barr virus (EBV), but it’s happening on a larger scale. 

LISTEN: EBV: The Chronic Viral Infection Linked To Brain Fog, Depression, Anxiety & Autoimmunity (+ Exactly What To Do About It) | Dr. Will Cole 

Underlying imbalances and factors that may contribute to post-COVID brain fog risk include: 

• Chronic inflammation
• Autoimmunity
• Gut dysbiosis and/or leaky gut 
• Histamine overload or mast cell activation syndrome (MCAS) 
• Dysautonomia 
• Low levels of certain nutrients 
• Exposure to mycotoxins (mold toxins), heavy metals, or other toxins 
• Variants in certain genes 
• Chronic or severe stress; history of trauma 

A Whole-Body Approach to Healing COVID-19 Brain Fog

I recommend a holistic, whole-body approach to healing from post-COVID brain fog. The first steps are always going to be the basics that I would recommend for healing from any chronic symptom, and for wellbeing in general. 

These include eating a balanced anti-inflammatory diet rich in phytochemicals, clean protein, and healthy fats; getting enough restful sleep; restricting alcohol intake; and following a regular exercise routine. 

From there, here are some more tools you can use to help restore your clarity and brain function. 

Identify Underlying Imbalances

As we talked about above, there are almost always underlying imbalances or issues that have created the conditions for the COVID virus to trigger long lasting symptoms like brain fog. So in order to bring about healing in a holistic manner, we need to identify what those imbalances or issues are. 

There are often multiple variables at play, which may include a buildup of toxins, dietary factors, gut microbiome imbalances, and other factors. (4) 

At the telehealth center, we take a detailed health history and often recommend specialized testing to get a better picture of what’s going on behind the scenes. This is the detective work that allows us to then make an effective, personalized plan of action. 

Labs we may recommend depending on the case would include gut microbiome/stool analysis, food sensitivity testing, testing for markers of inflammation and autoimmunity, micronutrient labs to look for any deficiencies, hormone testing, and toxin panels. 

Based on what we identify, we may need to replenish nutrients such as vitamins C and D, B vitamins, or magnesium; put together a modified eating plan; remove toxins; and/or work to reduce inflammation or balance hormones. Labs help us put together a clear roadmap of what to focus on. 

Regulate Inflammation and Mast Cells 

With long haul COVID and brain fog cases, we almost always see chronic inflammation, excess mast cell activation, and/or histamine overload as mechanisms of action. (5) These are ways in which the body is essentially overreacting to the viral trigger. 

To stabilize mast cells and regulate inflammation, some of the primary supports I recommend are: 

• Quercetin
• Vitamin C 
• Frankincense
• Boswelia 
• Garlic extract 
• Turmeric 
• Vitamins D3 and K2 

It’s also important to observe, monitor, and reduce mast cell triggers, which can include excess heat or cold, overexercising, and toxin exposure. 

Support the Gut-Brain Axis

Addressing gut health is one of the most important components of healing from brain fog and neurological symptoms. While again we may use testing to help guide more individualized protocols, there are a few go-to tools that can help most people with gut imbalances like dysbiosis. These include: 

• Prebiotics, probiotics, and/or postbiotics to support a healthy and diverse gut microbiome 
• Nutrients including L-glutamine and zinc carnosine to help strengthen the intestinal barrier in leaky gut 
• Bone broth and probiotic-rich fermented foods

Calm the Nervous System 

Work practices into your everyday life that help modulate neuroinflammation, strengthen vagal tone, and strengthen parasympathetic (rest and digest) nervous system function. 

There are so many different tools and approaches out there, and just like with exercise, the best options are usually the ones that you’ll be able to stick with. Here are a few great practices you can try: 

• Breathwork 
• Mindfulness meditation 
• Somatic practices
• Humming, singing, or gargling 

Next Level Healing Modalities 

There are a few additional functional medicine therapies that we might recommend if someone doesn’t sufficiently respond to the tools we’ve already listed. These aren’t first line therapies, but they can be very effective when used correctly: 

• Hyperbaric oxygen therapy (HBOT): Hyperbaric oxygen therapy involves sitting in a pressurized chamber and breathing in pure oxygen, which can speed up the body’s natural repair processes and reduce inflammation. A few small but compelling clinical trials have found that HBOT can reduce symptoms of long COVID including cognitive symptoms, fatigue, and sleep quality. (6) 
• Ozone therapy: Ozone therapy, which uses ozone gas to increase oxygen in the body, boost cellular metabolism, and enhance circulation, may also be helpful in some cases of long COVID. (7) 
• IVIG: I’ve also seen some patients experience significant improvements with the help of intravenous immunoglobulin (IVIG) therapy, which has been shown in small trials to successfully reduce symptoms of long COVID. (8) 

 READ MORE: Two Powerful Tools To Fight Off Long-Haul COVID 

Finding Answers Within the Body

Long COVID and brain fog symptoms can feel overwhelming, but I want you to know there’s always a reason your body is reacting this way, and therefore, a path forward. When we look at the body and mind as a whole, we can start getting to the root of the problem in order to heal. 

As one of the first functional medicine telehealth clinics in the world, we provide webcam health consultations for people around the globe.

Sources

• Fujimoto, Y., Abe, H., Eiro, T., Tsugawa, S., Tanaka, M., Hatano, M., … & Takahashi, T. (2025). Systemic increase of AMPA receptors associated with cognitive impairment of long COVID. Brain Communications, 7(5), fcaf337.
• Greene, C., Connolly, R., Brennan, D., Laffan, A., O’Keeffe, E., Zaporojan, L., … & Campbell, M. (2024). Blood–brain barrier disruption and sustained systemic inflammation in individuals with long COVID-associated cognitive impairment. Nature neuroscience, 27(3), 421-432.
• Post-COVID-19 condition, brain fog, and fatigue—what do we know now? eBioMedicine, eBioMedicine, Volume 105, 105252
• Chippa, V., Aleem, A., & Anjum, F. (2021). Post acute coronavirus (COVID-19) syndrome.
• Sumantri, S., & Rengganis, I. (2023). Immunological dysfunction and mast cell activation syndrome in long COVID. Asia Pacific Allergy, 13(1), 50-53.
• Hadanny, A., Zilberman-Itskovich, S., Catalogna, M., Elman-Shina, K., Lang, E., Finci, S., … & Efrati, S. (2024). Long term outcomes of hyperbaric oxygen therapy in post covid condition: longitudinal follow-up of a randomized controlled trial. Scientific reports, 14(1), 3604.
• Chirumbolo, S., Varesi, A., Franzini, M., Valdenassi, L., Pandolfi, S., Tirelli, U., … & Ricevuti, G. (2022). The Mito-Hormetic mechanisms of ozone in the clearance of SARS-CoV2 and in the COVID-19 therapy. Biomedicines, 10(9), 2258.
• Thompson, J. S., Thornton, A. C., Ainger, T., & Garvy, B. A. (2023). Long-term high-dose immunoglobulin successfully treats Long COVID patients with pulmonary, neurologic, and cardiologic symptoms. Frontiers in Immunology, 13, 1033651.