These are the twenty categories our assessment screens for. Each is a common pattern practitioners investigate when standard workups come back "normal" but you still don't feel right. Nothing on this page is medical advice — it's a starting vocabulary for a conversation with a qualified practitioner.
Medical disclaimer
This page is educational only. It is NOT medical advice, diagnosis, or treatment. Do not self-treat based on the information here. If you have symptoms, consult a licensed healthcare professional. If your symptoms are severe or worsening — chest pain, difficulty breathing, suicidal thoughts, severe bleeding — call your local emergency number.
An imbalance in the gut microbiome combined with weakened intestinal-barrier integrity. Considered a foundational driver of many chronic patterns in functional medicine.
Common symptoms
- Bloating, gas, irregular bowel habits
- Food sensitivities that seem to grow over time
- Skin flares (eczema, acne, rosacea)
- Brain fog after eating
Possible root causes
- Antibiotic exposure, chronic stress, low stomach acid
- Diet low in fiber and diverse plants
- Chronic infections (SIBO, H. pylori, parasites)
Labs a practitioner may consider
- GI-MAP or comprehensive stool analysis
- SIBO breath test
- Zonulin, calprotectin
A central-nervous-system pain amplification pattern often overlapping with fatigue, sleep disturbance, and cognitive complaints. Functional medicine looks upstream at mitochondria, infections, and HPA-axis strain.
Common symptoms
- Widespread muscle/joint pain and tenderness
- Unrefreshing sleep
- Post-exertional fatigue
- Cognitive difficulty ('fibro fog')
Possible root causes
- Chronic viral or tick-borne infections
- Mitochondrial dysfunction
- Trauma-driven nervous-system dysregulation
Labs a practitioner may consider
- Comprehensive thyroid panel
- Cortisol rhythm (4-point saliva)
- Vitamin D, magnesium, B12, ferritin
Borrelia burgdorferi and common co-infections (Bartonella, Babesia, Ehrlichia, Anaplasma) can produce multi-system, migrating symptoms that persist long after the initial exposure.
Common symptoms
- Migrating joint pain
- Night sweats, air-hunger, foot pain
- Neurological symptoms (tingling, twitching, cognitive changes)
- Symptom flares in cycles
Possible root causes
- Prior tick or insect exposure (may be unrecalled)
- Immune dysregulation allowing persistence
Labs a practitioner may consider
- Western blot (IgG/IgM)
- IGeneX or T-cell/ELISpot testing
- Babesia FISH, Bartonella FISH/PCR
Chronic Inflammatory Response Syndrome describes a persistent innate-immune activation triggered by biotoxins — most often water-damaged buildings and mold exposure.
Common symptoms
- Symptoms worse in certain buildings
- Static shocks, ice-pick pains, unusual thirst/urination
- Vision changes, difficulty finding words
- Post-exertional fatigue
Possible root causes
- Exposure to a water-damaged building
- Genetic HLA susceptibility (~24% of population)
Labs a practitioner may consider
- VCS (visual contrast sensitivity)
- Urine mycotoxins
- C4a, TGF-β1, MMP-9, MSH panel
- HLA-DR typing
The mitochondria are the cell's energy factories. When they underperform, symptoms are often 'everything, everywhere' — fatigue, exercise intolerance, cognitive slowing.
Common symptoms
- Fatigue not relieved by rest
- Post-exertional crash
- Poor exercise tolerance
- Muscle weakness or heaviness
Possible root causes
- Chronic infection, toxin burden (mold, metals)
- Nutrient deficiencies (CoQ10, B vitamins, magnesium)
- Long-term inflammatory diet or oxidative stress
Labs a practitioner may consider
- Organic acids test (OAT)
- Lactate/pyruvate ratio
- RBC magnesium, CoQ10, carnitine
A disruption in the brain–adrenal signaling that governs cortisol. Early on the pattern is usually 'wired-tired' with elevated cortisol; over months and years of unrelenting stress it commonly progresses to LOW cortisol output — a blunted, flat curve where the body can no longer mount a proper stress response. This late-stage low-cortisol picture is what most people mean by 'adrenal burnout' and it is frequently missed on standard morning-only blood cortisol tests.
Common symptoms
- Cannot get out of bed without caffeine; mornings feel impossible (low AM cortisol)
- Salt cravings, low blood pressure, dizziness on standing
- Hypoglycemia between meals — shaky, foggy, irritable if a meal is missed
- A 'flat' stress response: numb, detached, or shutdown instead of activated
- Wired at night, exhausted in the morning (earlier stage: reversed rhythm)
- Crashes after stress, exercise, or a busy day that take days to recover from
- Reduced stamina, low libido, poor exercise tolerance
Possible root causes
- Prolonged psychological or physiological stress, grief, overtraining
- Chronic blood-sugar dysregulation and under-eating
- Chronic infections, inflammation, or unresolved trauma driving the HPA axis into downregulation
- Sleep debt and circadian disruption
Labs a practitioner may consider
- DUTCH complete or 4-point salivary cortisol (captures the full diurnal curve — essential for detecting low cortisol)
- DHEA-S and cortisol:DHEA ratio
- ACTH, morning serum cortisol (screen only — misses low output later in the day)
- Fasting insulin & glucose
Beyond just TSH, functional medicine examines free T3, free T4, reverse T3, and antibodies — often finding suboptimal conversion or autoimmune activity (Hashimoto's) missed by standard panels.
Common symptoms
- Cold intolerance, dry skin, hair loss
- Constipation, weight changes
- Slow morning temperature
- Depression or anxiety
Possible root causes
- Hashimoto's autoimmunity
- Nutrient shortfalls (selenium, iodine, iron, zinc)
- Chronic stress-driven low T3
Labs a practitioner may consider
- TSH, free T3, free T4, reverse T3
- TPO and thyroglobulin antibodies
- Ferritin, selenium, zinc
Estrogen dominance, low progesterone, low testosterone, and peri/post-menopausal shifts often show up as mood, sleep, cycle, and body-composition changes.
Common symptoms
- PMS, heavy or irregular cycles
- Hot flashes, night sweats
- Low libido, mood swings
- Belly-weight gain
Possible root causes
- Impaired estrogen detoxification
- Chronic stress stealing progesterone precursors
- Insulin resistance
Labs a practitioner may consider
- DUTCH complete (hormones + metabolites)
- Serum sex hormones on cycle day 19-22
- SHBG, free testosterone
Cells become less responsive to insulin, driving blood-sugar swings, weight gain, and downstream inflammation. A root driver of many chronic conditions.
Common symptoms
- Energy crashes 2-3 hours after meals
- Cravings for carbs / sweets
- Difficulty losing weight, belly fat
- Skin tags, dark neck/armpit skin
Possible root causes
- Refined-carb and seed-oil-heavy diet
- Sedentary lifestyle
- Chronic stress and poor sleep
Labs a practitioner may consider
- Fasting insulin, HOMA-IR
- HbA1c, fasting glucose
- Triglycerides / HDL ratio
The immune system misidentifies self-tissue as foreign. Functional medicine looks at the shared drivers (gut, infections, toxins, stress) rather than treating each autoimmune label in isolation.
Common symptoms
- Migratory joint pain and stiffness
- Unexplained fatigue and flares
- Rashes, hair loss, dry eyes/mouth
- Family history of autoimmune disease
Possible root causes
- Leaky gut and food triggers
- Chronic infections
- Toxin burden (mold, heavy metals)
Labs a practitioner may consider
- ANA with reflex
- TPO, TG, tissue transglutaminase
- hs-CRP, ESR
Mast Cell Activation Syndrome and histamine intolerance produce multi-system inflammatory symptoms triggered by foods, stress, temperature, or exposures.
Common symptoms
- Flushing, hives, itching
- Headaches with red wine, aged cheese, fermented foods
- GI upset with 'healthy' foods
- Symptoms shift day-to-day
Possible root causes
- Gut dysbiosis, mold exposure
- Genetic DAO/HNMT variants
- Chronic stress and infection
Labs a practitioner may consider
- Serum tryptase (fasting)
- 24-hour urine N-methylhistamine
- DAO enzyme
Bioaccumulation of mercury, lead, cadmium, aluminum, and arsenic from environment, dental work, or diet can silently impair mitochondria and neurology.
Common symptoms
- Neurological symptoms (tremor, memory, mood)
- Fatigue and muscle weakness
- Metallic taste
- Sensitivity to chemicals
Possible root causes
- Amalgam fillings, seafood consumption
- Occupational exposure
- Impaired detox capacity
Labs a practitioner may consider
- Provoked urine metals panel
- Blood mercury / lead
- Hair mineral analysis (with caveats)
The liver's two-phase detoxification requires specific nutrients and healthy pathways. When impaired, everyday exposures accumulate and drive symptoms.
Common symptoms
- Sensitivity to alcohol, caffeine, medications, or fragrances
- Headaches from smells or chemicals
- Skin flares after exposures
- Slow recovery after drinking or eating certain foods
Possible root causes
- SNPs in MTHFR, COMT, CYP genes
- Nutrient shortfalls (B vitamins, glutathione precursors)
- High toxin load
Labs a practitioner may consider
- Organic acids test (methylation markers)
- Homocysteine, RBC folate, B12/MMA
- Glutathione
Persistent activation of brain immune cells (microglia) driven by gut, systemic inflammation, infections, or toxins — producing cognitive, mood, and sensory symptoms.
Common symptoms
- Brain fog, word-finding difficulty
- Anxiety or depression that feels 'inflammatory'
- Sensory sensitivity (light, sound)
- Cognitive symptoms flare with poor sleep or infection
Possible root causes
- Gut permeability and dysbiosis
- Chronic infections, mold
- Blood sugar swings, poor sleep
Labs a practitioner may consider
- hs-CRP, IL-6
- Homocysteine
- Omega-3 index
Shortfalls in protein, healthy fats, or fiber — or chronic under-eating — undermine every other system and are frequently overlooked when chasing exotic diagnoses.
Common symptoms
- Poor recovery after exercise
- Hair loss, brittle nails
- Constant hunger or extreme fullness
- Constipation from low fiber
Possible root causes
- Under-eating on restrictive diets
- Low protein intake (especially in women 40+)
- Ultra-processed food dominance
Labs a practitioner may consider
- Serum albumin, total protein, prealbumin
- Omega-3 index
- Fasting lipid panel
Sub-clinical shortfalls in specific vitamins and minerals (vitamin D, B12, iron, magnesium, zinc, iodine) drive fatigue, mood, and cognitive symptoms — and are among the most fixable root causes.
Common symptoms
- Fatigue disproportionate to lifestyle
- Restless legs, muscle cramps (magnesium)
- Cracks at mouth corners (B2/iron)
- Frequent infections, slow wound healing (zinc, D)
Possible root causes
- Malabsorption (gut dysbiosis, low stomach acid)
- Restrictive diets, ultra-processed food
- Medications (PPIs, metformin, oral contraceptives)
Labs a practitioner may consider
- 25-OH vitamin D, B12 / MMA, folate
- Ferritin and full iron studies
- RBC magnesium, zinc, selenium, iodine
Postural Orthostatic Tachycardia Syndrome and related autonomic dysregulation disorders where the autonomic nervous system struggles to regulate heart rate, blood pressure, temperature, and blood flow — especially with posture changes. Often overlaps with post-viral syndromes, hypermobility (hEDS), MCAS, and mitochondrial dysfunction.
Common symptoms
- Heart racing or pounding on standing (>30 bpm rise within 10 min)
- Lightheadedness, near-fainting, fatigue on upright activity
- Brain fog, exercise intolerance, heat intolerance
- Blood pooling / mottling in legs, cold extremities
- Nausea, early satiety, bladder urgency
Possible root causes
- Post-viral (COVID, EBV, enterovirus), post-concussion, post-surgical onset
- Hypovolemia, deconditioning, low sodium/aldosterone
- Overlap with MCAS, connective-tissue laxity (hEDS), Lyme, mold, autoimmunity
Labs a practitioner may consider
- 10-minute NASA lean test or tilt-table test
- Plasma/urine catecholamines, aldosterone, renin
- Ferritin, B12, comprehensive thyroid, morning cortisol
- Autoimmune / small-fiber neuropathy workup where indicated
Persistent multi-system symptoms — fatigue, brain fog, exercise intolerance, autonomic dysfunction, breathlessness — that continue for months after an acute viral infection (COVID-19, EBV, enterovirus, influenza). Functional medicine looks at mitochondrial injury, viral persistence, immune dysregulation, mast cell activation, and autonomic (POTS-like) overlap.
Common symptoms
- Fatigue and post-exertional malaise (crashes after mild activity)
- Brain fog, poor recall, word-finding trouble
- Air hunger, exercise intolerance, heart racing on standing
- New food/scent sensitivities, loss or distortion of smell/taste
- Sleep disruption, temperature dysregulation
Possible root causes
- Viral persistence (spike protein, EBV reactivation)
- Mitochondrial injury and impaired energy production
- Immune dysregulation, autoantibody formation, MCAS-like activation
- Autonomic nervous system injury (POTS-overlap)
- Microclotting and endothelial dysfunction
Labs a practitioner may consider
- 10-minute NASA lean test or tilt-table test
- EBV panel, comprehensive viral reactivation panel
- hs-CRP, D-dimer, fibrinogen, ferritin
- Comprehensive thyroid, morning cortisol, B12, vitamin D
- Small-fiber neuropathy / autoimmune workup where indicated
Chronic anxiety, unresolved trauma, and nervous-system dysregulation are not 'just in your head' — they physically re-shape immunity, gut function, hormones, and pain perception. Functional medicine treats the mind-body loop as a foundational root cause, not an afterthought.
Common symptoms
- Persistent anxiety, panic, or feeling 'on edge'
- Emotional numbing, dissociation, or shutdown under stress
- Chronic body tension (jaw, shoulders, chest, gut)
- Intrusive thoughts, nightmares, hypervigilance
- Difficulty with close relationships or trust
- Symptoms that flare with emotional stress
Possible root causes
- Adverse childhood experiences (ACEs) or adult trauma
- Chronic stress and unresolved grief
- Nervous-system 'stuck' in sympathetic (fight/flight) or dorsal-vagal (shutdown) states
- Gut-brain axis disruption feeding back into mood
Labs a practitioner may consider
- ACE (adverse childhood experiences) questionnaire
- DUTCH cortisol rhythm (chronic stress footprint)
- HRV (heart rate variability) tracking for autonomic tone
- Screening for PTSD, C-PTSD, GAD, and depression with a qualified clinician
A disorder of gut-brain communication where the intestine is structurally normal but functionally hypersensitive — driving pain, altered bowel habits, and unpredictable flares. Functional medicine looks upstream at SIBO, dysbiosis, food triggers, nervous-system tone, and unresolved stress.
Common symptoms
- Abdominal pain or cramping relieved (or worsened) by bowel movements
- Alternating constipation and diarrhea (IBS-M) or one dominant pattern (IBS-C, IBS-D)
- Bloating and visible distension worsening through the day
- Urgency, mucus in stool, or incomplete evacuation
- Symptoms clearly flare with stress or specific foods
Possible root causes
- SIBO (small intestinal bacterial overgrowth) — present in a large minority of IBS cases
- Post-infectious IBS after food poisoning (anti-vinculin antibodies)
- Dysbiosis, low stomach acid, poor bile flow
- Visceral hypersensitivity driven by nervous-system dysregulation
- FODMAP / histamine / gluten reactivity
Labs a practitioner may consider
- SIBO breath test (lactulose or glucose)
- Comprehensive stool analysis (GI-MAP)
- IBS-Smart antibodies (anti-CdtB, anti-vinculin) for post-infectious IBS
- Elimination diet (low-FODMAP, low-histamine) with practitioner guidance
In Ayurveda, Vata governs movement, breath, and the nervous system (air + ether elements). When elevated it manifests as dryness, coldness, restlessness, and irregularity.
Common symptoms
- Anxiety, racing thoughts, difficulty settling
- Dry skin/hair, cracking joints, cold hands and feet
- Constipation, bloating, irregular appetite
- Poor or interrupted sleep
Possible root causes
- Chronic stress, over-scheduling, irregular routines
- Cold, raw, or excessively light diet
- Overuse of stimulants and travel
Labs a practitioner may consider
- Nadi (pulse) & tongue assessment by a qualified Ayurvedic practitioner
- HRV, cortisol rhythm (as Western correlates)
Pitta governs metabolism, digestion, and transformation (fire element). When elevated it manifests as heat, inflammation, and sharp, intense responses.
Common symptoms
- Heat intolerance, flushing, acid reflux
- Skin inflammation (acne, rashes, rosacea)
- Irritability, perfectionism, criticism under stress
- Loose stools when stressed
Possible root causes
- Spicy, oily, or fermented foods in excess
- Overwork, driving ambition without recovery
- Sun and heat overexposure
Labs a practitioner may consider
- Ayurvedic dosha assessment
- hs-CRP, ferritin, LFTs (as inflammation correlates)
Kapha governs structure, lubrication, and stability (earth + water). When elevated it manifests as heaviness, congestion, and sluggishness.
Common symptoms
- Weight gain, especially around the middle
- Sinus/chest congestion, phlegm, heaviness
- Slow morning start, low motivation
- Emotional attachment, difficulty letting go
Possible root causes
- Heavy, sweet, oily diet; overeating
- Sedentary lifestyle, oversleeping
- Damp/cold environments
Labs a practitioner may consider
- Ayurvedic dosha assessment
- Fasting insulin, HbA1c, TSH (as metabolic correlates)
Agni is the digestive fire. When weak, food is incompletely metabolized and ama (metabolic residue) accumulates — considered a root of most disease in Ayurveda.
Common symptoms
- Coated tongue in the morning
- Heaviness or brain fog after meals
- Undigested food in stool, foul-smelling gas
- Loss of taste for food, dull skin
Possible root causes
- Eating when stressed, late-night eating, snacking constantly
- Cold drinks with meals, poor food combining
- Sedentary lifestyle, weak digestive rituals
Labs a practitioner may consider
- Ayurvedic tongue and pulse assessment
- Comprehensive stool analysis (as Western correlate)
Ojas is the refined essence of nourishment — the substrate of immunity, vitality, and resilience. Depletion follows chronic stress, illness, or over-exertion.
Common symptoms
- Frequent illness, slow recovery
- Deep fatigue, low vitality
- Feeling 'burnt from within', emotional fragility
- Loss of glow in skin and eyes
Possible root causes
- Prolonged stress, grief, or overwork
- Chronic infection, over-fasting or malnutrition
- Excessive stimulation and inadequate rest
Labs a practitioner may consider
- Ayurvedic ojas assessment (pulse, complexion, sattva)
- Immunoglobulins, DHEA-S, ferritin, vitamin D (as Western correlates)
In Traditional Chinese Medicine, Qi is vital energy. Spleen or Lung Qi deficiency presents as low energy, weak digestion, and vulnerability to illness.
Common symptoms
- Deep fatigue not relieved by rest
- Soft or tired voice, shortness of breath
- Easy sweating, pale complexion
- Loose stools, poor appetite
Possible root causes
- Overwork, chronic worry, irregular meals
- Cold and raw foods weakening Spleen Qi
- Post-viral state, chronic illness
Labs a practitioner may consider
- TCM pulse and tongue diagnosis
- CBC, ferritin, thyroid panel (as Western correlates)
Yin is the cooling, moistening, restorative substance. When deficient, heat and dryness rise — often seen in perimenopause, chronic stress, and burnout.
Common symptoms
- Night sweats, warm palms and soles
- Dry mouth, dry eyes, dry skin
- Insomnia, especially waking after midnight
- Afternoon flushing, hot flashes
Possible root causes
- Chronic overwork without rest
- Aging, perimenopause/andropause
- Excessive stimulants, spicy foods, alcohol
Labs a practitioner may consider
- TCM pulse and tongue diagnosis
- Sex hormone panel, cortisol rhythm, thyroid (as Western correlates)
Yang is the warming, activating force. Kidney Yang deficiency presents as coldness, low drive, and fluid retention — often paralleling hypothyroid and adrenal patterns.
Common symptoms
- Cold lower back and knees
- Low libido, low motivation
- Frequent, clear urination
- Pale complexion, edema
Possible root causes
- Chronic exhaustion, cold exposure
- Aging, long illness
- Over-restriction of nourishing foods
Labs a practitioner may consider
- TCM pulse and tongue diagnosis
- TSH, free T3/T4, reverse T3, DHEA-S (as Western correlates)
The Liver in TCM ensures the free flow of Qi and emotion. When Liver Qi is constrained — often by stress or suppressed emotion — symptoms shift with mood and cluster on the sides of the body.
Common symptoms
- Sighing, lump-in-throat sensation
- Rib-side or chest tension
- PMS with irritability and breast tenderness
- Digestive symptoms that flare with stress
Possible root causes
- Chronic stress, unexpressed anger or grief
- Sedentary lifestyle
- Alcohol and greasy food excess
Labs a practitioner may consider
- TCM pulse and tongue diagnosis
- LFTs, sex hormone panel (as Western correlates)
When Blood does not move freely, it stagnates — producing fixed, sharp pain and dark, clotted flow. Often follows long-standing Qi stagnation, cold, or trauma.
Common symptoms
- Fixed, stabbing pain (headaches, menstrual cramps)
- Dark, clotted menstrual flow
- Purple-tinged tongue or lips
- Visible spider veins, easy bruising
Possible root causes
- Long-standing Qi stagnation
- Cold exposure, trauma or surgery
- Chronic inflammation
Labs a practitioner may consider
- TCM pulse and tongue diagnosis
- Coagulation panel, hs-CRP, iron studies (as Western correlates)
Methylation is a biochemical process that turns genes on and off, builds neurotransmitters, clears histamine, and detoxifies. Common variants (MTHFR C677T, A1298C, MTR, MTRR, COMT) can slow this pathway, producing wide-ranging effects on mood, energy, detox, and cardiovascular health.
Common symptoms
- Persistent anxiety, depression, or mood swings that don't fully respond to standard care
- Histamine intolerance and estrogen-related symptoms
- Worsening on folic-acid-fortified foods or standard multivitamins
- Family history of miscarriage, early heart disease, or clotting issues
Possible root causes
- MTHFR / MTR / MTRR / COMT genetic variants
- Low B12, folate, B6, riboflavin, choline, magnesium, or zinc
- High oxidative stress or heavy toxic burden depleting methyl donors
Labs a practitioner may consider
- MTHFR / methylation SNP panel
- Homocysteine, MMA, active B12, RBC folate
- Organic acids test (methylation & neurotransmitter markers)
Neurodevelopmental patterns with a strong genetic and neurobiological basis, often amplified by gut, immune, methylation, mitochondrial, and environmental factors. Functional medicine does not 'cure' neurodivergence — it works to reduce the physiological load that worsens focus, sensory overwhelm, sleep, and regulation.
Common symptoms
- Lifelong difficulty with attention, executive function, or task follow-through
- Sensory sensitivities (sound, light, textures, food)
- Social overwhelm, strong routines and interests, emotional regulation challenges
- Sleep, gut, and immune issues that commonly co-travel
Possible root causes
- Genetic and neurodevelopmental factors
- Gut dysbiosis, food sensitivities, and gut–brain axis inflammation
- Methylation, mitochondrial, and mineral (zinc, magnesium, iron) imbalances
- Toxic burden and chronic infections that amplify neuroinflammation
Labs a practitioner may consider
- Comprehensive stool analysis, organic acids test
- Methylation SNPs, homocysteine, active B12, RBC folate
- Ferritin, zinc, copper, magnesium RBC
A subjective but very real cognitive haze — slow processing, poor recall, word-finding trouble, and difficulty holding a thought. Rarely a diagnosis on its own; almost always a signal of an upstream driver such as neuroinflammation, gut dysbiosis, mold, blood-sugar swings, poor sleep, or mitochondrial strain.
Common symptoms
- Feeling like you're thinking through cotton wool
- Word-finding difficulty and short-term memory lapses
- Worse after meals, poor sleep, or specific foods (gluten, dairy, sugar)
- Worse in water-damaged buildings or with hormonal shifts
Possible root causes
- Neuroinflammation, gut dysbiosis, mold/CIRS
- Blood-sugar dysregulation, poor sleep, HPA-axis strain
- Mitochondrial dysfunction, nutrient deficiencies (B12, iron, omega-3)
Labs a practitioner may consider
- hs-CRP, homocysteine, HbA1c, fasting insulin
- GI-MAP or stool analysis; mycotoxin panel where indicated
- Ferritin, active B12, vitamin D, omega-3 index
A serious, multi-system illness defined by profound fatigue lasting 6+ months that isn't relieved by rest, post-exertional malaise (crashes after physical OR mental effort), unrefreshing sleep, and cognitive impairment. Functional medicine looks at mitochondrial function, chronic infections, autonomic dysregulation, and HPA-axis burnout as commonly overlapping drivers.
Common symptoms
- Profound fatigue substantially reducing what you can do, for 6+ months
- Post-exertional malaise — crashes 12–72 hours after even mild exertion
- Unrefreshing sleep no matter how many hours
- Cognitive impairment ('brain fog') and orthostatic intolerance
Possible root causes
- Post-viral triggers (EBV, COVID, enteroviruses)
- Mitochondrial dysfunction and impaired energy production
- Autonomic nervous system dysregulation (POTS overlap)
- HPA-axis burnout with low cortisol output
Labs a practitioner may consider
- Viral panels (EBV, HHV-6, CMV), tick-borne panel
- Organic acids (mitochondrial markers), amino acids
- 4-point salivary cortisol, tilt-table / NASA lean test
Delayed, dose-dependent immune and digestive reactions to specific foods — most often gluten, dairy, eggs, soy, corn, nuts, nightshades, or high-histamine foods. Unlike true IgE allergies, symptoms show up hours to a day later as bloating, brain fog, skin flares, joint aches, headaches, or fatigue, which is why the trigger is usually missed. Sensitivities almost always sit on top of a leaky gut, dysbiosis, or low digestive capacity — treating the terrain is what shrinks the reactive list over time.
Common symptoms
- Bloating, gas, or loose stools 2–24 hours after certain meals
- Brain fog, headaches, or fatigue after eating
- Skin flares — eczema, acne, rosacea, itching, hives
- Joint aches, stiffness, or muscle soreness that tracks with diet
- Chronic congestion, post-nasal drip, or dark under-eye circles
Possible root causes
- Intestinal permeability ('leaky gut') from stress, alcohol, NSAIDs, or infection
- Gut dysbiosis, SIBO, H. pylori, candida, or parasites
- Low stomach acid or poor bile flow (undigested proteins reaching the small intestine)
- Histamine overload or MCAS masquerading as food reactions
- Undiagnosed celiac disease or non-celiac gluten sensitivity
Labs a practitioner may consider
- Celiac panel (tTG-IgA, total IgA) before removing gluten
- Structured 3–4 week elimination and reintroduction (the diagnostic gold standard)
- Comprehensive stool test (dysbiosis, digestive markers, calprotectin)
- SIBO breath test, H. pylori testing
- Zonulin, diamine oxidase (DAO), or histamine markers where relevant
Content on this page is for educational purposes only and does not constitute medical advice, diagnosis, or treatment. Always consult a licensed medical professional before making changes to your care.