Non-microbiome causes
Anaemia, iron/B12/folate deficiency, thyroid disease, sleep apnoea, depression, chronic infection, celiac disease, IBD, medication side effects, dehydration, hyperglycaemia, non-GI chronic illness.
Relevant tests
Clinical history; CBC, ferritin, B12, folate, TSH, HbA1c, celiac serology when indicated; calprotectin if inflammatory GI features. Microbiome test not first-line for fatigue.

Fatigue, persistent low energy or exertional intolerance, alongside gut symptoms requires standard medical workup before microbiome interpretation. Anaemia from occult GI blood loss, celiac disease, IBD, thyroid dysfunction, and sleep disorders are common explanations that stool sequencing does not detect.

Reports linking fatigue to dysbiosis, LPS, or low butyrate producers extrapolate from metabolic and cohort studies, not from validated fatigue endpoints on your panel.


Before anything else, clinical workup first

With a clinician, consider screening for:

  • Anaemia (iron, B12, folate), especially with diarrhoea or celiac risk
  • Thyroid disease (TSH)
  • Celiac serology if compatible symptoms
  • Diabetes or metabolic disturbance
  • Depression, sleep apnoea, medications
  • Inflammatory GI disease if diarrhoea, blood, weight loss, calprotectin

See Red flags.


Decision tree, after basic labs

PatternThink aboutRead next
Elevated calprotectin, GI inflammationIBD workupIBD vs functional, Calprotectin
Diarrhoea + weight loss + anaemiaMalabsorption, IBD, celiacClinical pathway, not report-first
Fatigue after gastroenteritis, ongoing IBSPost-infectious overlapPost-infectious IBS
IBS + poor sleep / stressGut–brain axis overlapStress, sleep & exercise
Report cites LPS / endotoxemiaResearch association in metabolic cohortsMetabolic health & LPS, not individual diagnosis
Report cites leaky gut / low butyrateIndirectIntestinal barrier, SCFAs

Evidence-tier table, framing only

ApproachEvidence tierNotes
Treat anaemia, thyroid, celiac, IBD when foundStrongBefore supplement stacks
Calprotectin + clinical assessment for inflammatory featuresStrongGut inflammation markers
Sleep hygiene / CBT / activity (IBS comorbidity)Moderate for symptom clustersStress, sleep & exercise
Low-FODMAP if IBS symptoms drive quality of lifeStrong for IBS endpointsLow-FODMAP
Probiotics for fatigue from reportWeakStrain-specific; not fatigue indication
Microbiome test explains fatigueLowReading your report

What consumer microbiome reports cannot establish

QuestionCan sequencing answer it?
Am I anaemic or hypothyroid?No
Do I have celiac disease?No
Is fatigue from LPS translocation?No, blood markers research-only
Will a probiotic improve energy?No