As chemistry PhD and just a guy who is passionate about modern biotech science and studies of aging I don't think that some simple chemicals could ever "reverse aging" or "rejuvenate" skin. Yes, it may rehydrate skin and make it look younger but it's not making it younger. Only way to reverse aging is to use experimental gene treatments. There are intersting accomplishments made by Shinya Yamanaka who has developed a way to slow down aging of mice to achieve 50% longevity increase and rejuvenation. Yet rejuvenating humans is a bit too much for modern science, there is one brave woman - Liz Parrish who tried hTERT gene therapy on herself but results are not clear. Anyway, there is no real rejuvenating treatment on the maket right now and this methylene blue is just another type of cosmetic compound like hyaluronic acid.