I would think it's safe to assume that the material is food safe and would be okay for either PG or VG (but I could go on and on about crazy assumptions I've made in the past). I was just about to buy a set of squirt bottles for mustard and ketchup at my local cooking store when I found clear squirt bottles that were a lot easier to squeeze. If my assumption that if a storage bottle is food safe then it's PG or VG safe is flawed, please let me know as I paid no attention to the actual material used.