I make a lot of my own juices from 70/30 PG/VG, flavorings, nicotine and pure H2O. My fave is menthol which I make by adding some menthol crystals to the above mixture, much like many commercial makers. I'm finding that I sometimes get slight chest pain when vaping this mixture and I read that this is a noted and recognized side effect in some people from inhaling real menthol. I just thought I'd mention this in case anyone else is so affected by it. I'm fit and healthy and no other flavours have this effect on me. This won't affect everyone but may be noticed by some who get through a lot of menth juice. Perhaps someone can suggest a good synthetic alternative to using genuine menthol crystals in my juice? Happy Christmas!