Is IgG useful for longevity?

The utility of IgG testing for longevity is questionable. IgG (immunoglobulin G) is an antibody involved in immune memory and food exposure. Many consumer tests claim that elevated IgG to certain foods indicates intolerance and that avoiding those foods can improve health and longevity. However, the scientific consensus is weak: IgG responses often reflect normal dietary exposure, not pathology. Randomized controlled trials have not demonstrated that IgG-guided elimination diets improve long-term health outcomes or lifespan. For longevity, validated biomarkers include inflammatory markers (e.g., hs-CRP, IL-6), metabolic markers, and epigenetic clocks. IgG testing alone lacks predictive power for aging. Moreover, unnecessary dietary restrictions can lead to nutrient deficiencies and reduced quality of life. While immune function is relevant to healthy aging, measuring IgG in isolation is not a reliable strategy. Consumers should be cautious of marketing claims and consider comprehensive assessments that include genetics, microbiome, and lifestyle. In summary, current evidence does not support IgG as a useful tool for longevity.