What role does IgG play in stress?

The role of IgG in stress is a nuanced topic. IgG (immunoglobulin G) is the most abundant antibody in blood, crucial for long-term immunity against recurring pathogens. Chronic stress, via cortisol release, can modulate immune function, including antibody production. Some research suggests stress may alter IgG levels—either increasing or decreasing them—depending on stress duration, type, and individual physiology. However, the evidence is weak: most findings come from animal models or small human studies, and no consensus exists on clinical relevance. The provided context does not contain any information about IgG and stress, so this answer is based on general scientific knowledge. In practice, measuring IgG as a stress biomarker is not validated. Direct-to-consumer tests claiming to link IgG to stress often lack scientific backing. Conclusion: while a biological link is plausible, current evidence is insufficient to support clinical use. Stress management should rely on established methods (e.g., sleep, exercise, mindfulness) rather than IgG testing.