I'm running low on juice and i'm noticing on some of the sites i look for juice are starting to give the choice of VG or PG. I taking a wild guess i think VG was the norm and what i have most likly been vaping on for the last month. So then if that's true what is PG? does it hit smoother. What's the difference someone plz help me out here. If i don't make an order today i'm worried i may run out before i get rejuiced.