PG = Propylene Glycol
VG = Vegetable Glycerin
VG is thicker than PG. Many report they get a greater amount of vapor using VG. VG is also sweeter than PG. If you don't like an additional sweet taste, VG may not be for you. Most liquid is PG based. Many folks use VG because they have an allergic reaction to the PG. (Headaches, itchy throat, etc). If you are allergic, you will need to
buy VG based liquid and cut with VG.
I use PG based liquid and cut with PG only and I am happy with my vapor and flavor level........