oral glutathione skin whitening evidence PDF) for lightening: a regnant myth or evidence-based verity? Glowing Skin: IV Glutathione and
Description
pmid:15082291 46

[DOI] [PubMed] [Google Scholar] 42.Pugliese M., Biondi V., Merola G., Landi A., Passantino A
Most of these substances do not have an immediate effect after a single administration and must be used for some length of time before there is a measurable improvement

In the meta-analysis by Yang et al

Yes, it does
Clean both vial tops with alcohol swabs before starting
