intravenous glutathione for skin lightening lightening: a regnant myth or evidence-based verity? A New Skin Lightening Procedure

Though the gene encoding DSIP has not been identified and its receptor remains unknown, emerging studies indicate that its activity may be mediated through NMDA receptors in the brain and 1-adrenergic pathways in peripheral tissues

So really, everyone is just doing their best guess and playing it safe by saying to avoid these ingredients

Alcohol Alcoholism

Because of this preservative system, bacteriostatic water is frequently selected for laboratory environments where repeated vial access may be required as part of established research procedures

PMC Article PMC4425239

IdeS, a novel streptococcal cysteine proteinase with unique specificity for immunoglobulin G