Brain Fog
When thinking feels like wading through mud. Brain fog isn't a diagnosis—it's a symptom with many possible causes. Poor concentration, forgetfulness, mental fatigue, and difficulty thinking clearly. Understanding the root cause is key to clearing the fog.
Common Causes
Inflammation
Neuroinflammation from any source. Cytokines affect cognition. "Sickness behavior."
Poor Sleep
Sleep deprivation impairs cognition directly. Brain clears waste during sleep.
Blood Sugar Issues
Hypoglycemia, reactive hypoglycemia. Brain needs steady glucose. Crashes cause fog.
Thyroid Dysfunction
Hypothyroidism classic cause. Low metabolism = slow brain. Check full thyroid panel.
Nutrient Deficiencies
B12, iron, vitamin D common. B vitamins for neurotransmitters. Iron for oxygen delivery.
Gut Issues
Gut-brain axis. SIBO, leaky gut cause systemic inflammation. Food sensitivities.
Additional Causes to Consider
Physical
- Dehydration: Brain is 75% water
- Mold exposure: Mycotoxins affect brain
- Heavy metals: Mercury, lead neurotoxic
- Chronic infections: Lyme, EBV reactivation
Lifestyle/Other
- Stress/burnout: Cortisol affects memory
- Medications: Antihistamines, statins, benzos
- Hormonal changes: Menopause, low testosterone
- Post-viral: Long COVID brain fog
Workup Considerations
Thyroid Panel
Full panel: TSH, free T4, free T3, antibodies. Not just TSH.
B12, Iron, Ferritin
Common deficiencies. Optimal levels, not just "normal."
Vitamin D
Often low. Aim for 40-60 ng/mL. Affects brain function.
Blood Sugar
Fasting glucose, HbA1c. Consider CGM to track patterns.
Inflammatory Markers
CRP, ESR. Check for systemic inflammation.
Gut Testing
SIBO breath test. Stool analysis. Food sensitivity if suspected.
Clearing the Fog
Fix Root Cause
Find and address underlying issue. Thyroid, deficiency, gut problem.
Optimize Sleep
7-9 hours. Consistent schedule. Dark, cool room. No screens before bed.
Stable Blood Sugar
Protein with meals. Lower glycemic. Regular meals. No sugar crashes.
Anti-Inflammatory Diet
Mediterranean, whole foods. Reduce processed, sugar. Omega-3s.
Hydration
Dehydration impairs cognition. Electrolytes too. Simple but effective.
Movement
Exercise increases BDNF. Blood flow to brain. Clears mental fog.