These are the eighteen 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. Chronic stress, blood-sugar swings, and inflammation can dysregulate the rhythm, producing wired-tired patterns.
Common symptoms
- Wired at night, exhausted in the morning
- Crashes after stress or intense exercise
- Salt or sugar cravings
- Lightheadedness on standing
Possible root causes
- Chronic psychological or physiological stress
- Blood-sugar dysregulation
- Sleep debt
Labs a practitioner may consider
- DUTCH complete or 4-point saliva cortisol
- DHEA-S
- 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
See which of these show up in your responses
Seven minutes. Seventy questions. A private, personalized snapshot of where your body may be asking for attention.
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.