I don't know either, but maybe give these a look:How does one know if they are sensitive to PG? I hear so many people saying they have to go to a higher VG content (some even say 100% VG) because they have an allergy to PG .... exactly what does it feel like?
Reason I ask is that lately every once in a while after a vape it feels like my lips/tongue/mouth is full of a peppery numbing "something". I first thought it was too high nic content .... so I've stepped it down to 12mg ... then I thought it may be I was getting juice into my mouth ... but I don't really inhale that deep (and there is no "gurgling") and no evidence if juice in the mouthpiece ... then I thought it may be voltage/wattage settings .... so I adjusted down until there was no taste, and up until I was afraid I'd cause a power failure on the eastern seaboard ... but nothing helps.
I'll be happily vaping thinking ummmmmmmm butter scotch then all of a sudden phew phew phew pepper taste/numb mouth .... switch tanks, and phew phew phew pepper/numb mouth for a few vapes then Mmmmmmmmm graham cracker and all of a sudden the cycle repeats until it gets to the point that I can't taste anything no matter what tank with what juice I have .... just the pepper/numb mouth.
http://www.e-cigarette-forum.com/fo...ty-acne-throat-problems-shortness-breath.html
http://www.e-cigarette-forum.com/forum/health-safety-e-smoking/328371-pg-allergy-symptoms.html


That's because they aren't big girl batteries when *you* use them.