What’s really causing my brain fog?
Brain fog is often being driven by a deeper cascade, not just poor focus or lack of sleep. In the script, Dr. Kenny explains that common drivers include post-viral inflammation, blood-brain barrier stress, microglial activation, mitochondrial energy loss, and oxidative stress, all of which can leave your brain running in a low-power, protective mode.
Brain fog is usually a pattern, not one diagnosis
One of the most helpful ideas in the video is that brain fog is not one disease you can point to on a basic lab test. It is more like a symptom cluster that can show up across different conditions, including chronic fatigue, long COVID, mold-related illness, and other inflammatory patterns.
What ties these together is that the body starts shifting its priorities. Your energy and immune systems move toward protection and survival, and the brain gets caught in the middle. As a functional medicine practitioner, I think this matters because it changes the question. Instead of asking only, “How do I get rid of brain fog?” we ask, “What is pushing my brain into low-power mode in the first place?”
Mitochondria may be conserving energy
The script puts a major spotlight on mitochondria, the tiny energy regulators inside your cells. When things are going well, they help support focus, memory, and mental stamina. But when the body senses a threat, like a lingering virus, inflammation, mold toxins, or chronic stress, mitochondria can shift from performance mode into defense mode.
That means less energy is available for higher-order brain functions. This is why brain fog can feel so strange and inconsistent. Some days you function fairly well. Other days words, thoughts, or attention feel just out of reach. At Dr. Kenny’s clinic, we often look at this as a processing-power problem, not a willpower problem.
Inflammation can breach the brain’s protection
The video also explains that brain fog often follows a bigger inflammatory cascade. A trigger, like COVID, Epstein-Barr, mold, gut inflammation, or chronic stress, activates the immune system. That can put pressure on the blood-brain barrier, the protective layer that helps control what gets into the brain environment.
Once that barrier becomes more permeable, inflammatory molecules can cross through and activate microglia, the brain’s immune cells. Those cells are supposed to protect you, but when they stay activated too long, they add more inflammation and keep the cycle going. That is part of why brain fog can linger longer than people expect.
Low resources and oxidative stress can keep the loop going
The script highlights two more pathways, constrained resources and oxidative stress overload. Brain cells need stable ATP and key nutrients to function well, especially B vitamins, CoQ10, carnitine, and magnesium. If stress, infection, or inflammation keeps draining those supplies, energy production can fall even further.
At the same time, oxidative stress can damage cells faster than the body can keep up with repair. That can worsen inflammation, keep the blood-brain barrier stressed, and extend the fog. The bigger takeaway is simple. Brain fog is often not random and it is not just in your head. It is usually a clue that inflammation, mitochondrial strain, barrier dysfunction, and resource depletion are all interacting underneath the surface. Once you start identifying which pathway is driving yours, recovery becomes much more targeted and much less mysterious.
Additional Resources:
- If chronic stress seems to make your focus, sleep, and resilience worse, Can stress really mess up my hormones or thyroid? gives helpful context on how stress chemistry can ripple into cognitive symptoms.
- If you want a better look at the chemistry underneath brain fog, What is an Organic Acids Test (OAT) Good for? shows how this test can reveal mitochondrial, oxidative stress, and nutrient roadblocks.
- In What’s Behind Brain Fog? From Chronic Fatigue to Long COVID, Dr. Kenny explains how brain fog often reflects a cascade involving inflammation, blood-brain barrier stress, microglial activation, and mitochondrial energy loss.
- A 2025 review found that post-COVID brain fog is linked to mitochondrial dysfunction, oxidative stress, and reduced ATP production, supporting the idea that the brain can feel offline when cellular energy is constrained.
If your brain fog still does not make sense and you want to uncover the pattern underneath it
Answered by Dr. Kenny Mittelstadt, DACM, DC, IFMCP
Certified functional medicine practitioner specializing in advanced lab testing and personalized healing protocols to uncover root causes of health roadblocks.