The research found only three small studies showing topical or oral glutathione may lighten skin, but IV injections (the popular choice) have zero evidence of working—and the Philippines FDA actually warned against them. The big problem: we don't know how long results last, whether you need to keep taking it forever, or what the best dose is.

This was a literature review examining existing research on glutathione's skin-lightening claims, looking at how it works in the body, what form works best, and what evidence actually exists.

Funding not disclosed in abstract