Just like smoking, effects vary per person. Though it is known that a very small percentage of people have had side effects from the propylene glycol in e-liquids. The negative PG side effect may cause sinus or throat irritation and a dry mouth. The ratio of our PG/VG blend in our brands are 70/30, 50/50, and Max VG. If you are one of the few with these effects, consider trying our line of 50/50 or Max VG flavours.