Oops, was not refering to NO2, never tried it.....but most likely it is pro-hormone junk.....and doesn't do shit! But again I've never tried it even though it does contain arginine. However, I did take L-arginine powder for several weeks 25g before bed......felt fuller while taking it, and that stuff has to be nature's viagra! Makes you pop non stop.....but I don't take it anymore. There are a lot of horrible tasting supplements that I can stand, but the arginine powder made me gag everytime I took it.