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.

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.

In people with Graves' disease taking antithyroid medications, adding selenium may lead to faster normalization of thyroid hormone levels at six months, but this effect does not last until nine months and differs depending on the type and amount of selenium used.

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 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.

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.