Evidence check: IgG in the context of sleep

Claims that IgG (immunoglobulin G) testing can help with sleep issues are not supported by evidence. IgG is commonly measured in commercial 'food intolerance' panels, but these tests lack validation for diagnosing intolerances or sleep disorders. No robust clinical studies demonstrate a causal link between IgG levels and sleep quality. Sleep problems typically have multifactorial causes—stress, poor sleep hygiene, hormonal imbalances, sleep apnea, or true IgE-mediated allergies. IgG tests produce many false positives and may lead to unnecessary dietary restrictions that impair quality of life without improving sleep. Anyone with chronic sleep disturbances should seek medical evaluation (e.g., polysomnography, thyroid function, iron status) rather than rely on consumer IgG panels. The evidence for IgG in the context of sleep is purely marketing-driven.