It is unclear whether selenium supplements help treat Graves' disease because studies have varied widely in how they gave selenium, did not measure patients' initial selenium levels, and used lab tests instead of actual health outcomes like disease remission.

There is no clear evidence that taking selenium supplements improves key outcomes for people with Graves' disease, such as reducing relapses, improving quality of life, or easing eye symptoms.

Taking selenium supplements does not keep thyroid hormone levels improved in people with Graves' disease beyond six months; after nine months, these levels return to what they were before treatment, even if supplementation continues.

Taking selenium supplements after standard treatment for Graves' disease does not reliably lead to better long-term remission, and blood levels of selenium do not predict whether the disease will return.

Taking selenium supplements does not lead to better quality of life for people with Graves' hyperthyroidism who do not have eye symptoms, as studies show no meaningful difference in mood or self-reported symptoms compared to taking a placebo.

In patients with mild, active Graves' orbitopathy lasting less than seven months, selenium supplementation may be linked to better quality of life and fewer eye symptoms, but these findings are based on one study and have not been confirmed by others.