Evidence check: IgG in the context of fatigue

IgG antibody testing for foods is often marketed as a way to identify food sensitivities that cause fatigue, but the scientific evidence is weak. IgG antibodies are a normal immune response to food exposure and do not reliably indicate intolerance or disease. High-quality studies have failed to show a consistent link between elevated IgG levels and symptoms like fatigue. Professional medical societies, including the European Academy of Allergy and Clinical Immunology, advise against using IgG tests for diagnosing food intolerance because they can lead to unnecessary dietary restrictions and nutritional deficiencies. In the context of chronic fatigue, more evidence-based causes such as iron deficiency, thyroid dysfunction, sleep disorders, or mental health issues should be investigated first. While MyBody-X offers DNA and metabolism tests, IgG testing is not part of their evidence-based product line. Consumers should be cautious: IgG tests for fatigue are not supported by robust clinical evidence and may mislead people away from proper medical evaluation. The evidence rating for this claim is 'marketing' due to the lack of scientific validation.