Can IgG Unverträglichkeitstest help with fatigue?

IgG food sensitivity tests are often marketed for fatigue, but the scientific evidence is weak. Major allergy organizations (e.g., AAAAI) advise against them because IgG antibodies commonly reflect normal food exposure, not intolerance or disease. Fatigue is a complex symptom with many potential causes (sleep, stress, iron deficiency, thyroid issues, etc.). An IgG test cannot reliably identify the root cause. Evidence grade: marketing/unclear. A thorough medical workup is more appropriate than relying on such tests.