What role does IgG Unverträglichkeitstest play in fatigue?

The IgG food intolerance test is often marketed for fatigue, but lacks scientific support. IgG antibodies are normal memory antibodies to foods and do not indicate intolerance or allergy. Medical societies (e.g., EAACI, DGAKI) advise against these tests because they can lead to unnecessary dietary restrictions and misinterpretation. Fatigue has many causes (sleep deprivation, stress, nutrient deficiencies, thyroid issues) that an IgG test does not address. The evidence is weak – it is a marketing product without clinical validation. A proper workup includes medical history, blood count, vitamin and hormone panels. The test provides no actionable information for fatigue.