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    Ingredient guide · Ingredient reference

    Glutathione and pigmentation: two of six sites differed from placebo

    A four-week study found limited site-specific changes. It did not establish durable effects or long-term safety.

    Read the evidence ↓

    Supplement Science Insights Editorial Team

    Published September 23, 2026

    The study and its comparison

    Sixty healthy medical students were randomized to oral glutathione 500 mg daily in divided doses or placebo for four weeks. Melanin indices were measured at six sites. [1]

    Although measurements fell at all six sites in the glutathione group, the changes exceeded placebo significantly at only two: one facial site and one exposed forearm. [1]

    What the finding establishes

    The small, brief trial leaves persistence and long-term safety unresolved. Oral findings cannot validate injections or identify a best skin-lightening product. Funding and conflicts were not established from the abstract. Normal skin-color variation does not require treatment. [1]

    A hypothetical distinction

    Imagine measurements fall in both groups. Only the comparison with placebo tests the added effect.

    Interpretation checklist — Glutathione and pigmentation
    DetailInterpretation
    Measured outcomeKeep the endpoint specific
    Study preparationNot every retail product
    Remaining uncertaintyNot resolved by a mechanism
    Glutathione and pigmentation: two of six sites differed from placebo — original article outline diagram
    Original editorial diagram of this article’s sections; no product photograph or clinical finding is depicted.

    Sources for this article

    1. Glutathione as an oral whitening agent: a randomized, double-blind, placebo-controlled study.
      Source consulted: 2026-09-19. This is a reference resource, not a claim that we conducted the studies or tested a product.