I've been getting some headaches lately and was wondering if vaping could have anything to do with them. So i messed around with the juices and started to draw some preliminary conclusions. Sometimes, I definitely drink less water than i should, and this likely plays a big role. I need to drink quite a bit of water to function optimally, more than some other people, and i sweat a lot in the summer. I know that both PG and VG tend to suck water out of the body so I will be hydrating myself more. It could be the nicotine level, the fact that i've been playing with higher PG in my juices lately, or some of the flavors I have are crap. I remember getting a headache from some cheap Liqua juice when i first started vaping, and have avoided that brand since. I am kinda doubtful it is the nicotine as i was vaping 6-8ml per day of 6mg/ml juice not too long ago, then have gone down to 4 and 3mg/ml, I am vaping a bit more of this, but not by much. Maybe my new coil builds are more efficient in delivering nicotine, or maybe i just need to avoid PG altogether, although i haven't had any issues with 75/25 VG/PG and have used this base for all my juices until recently, when i started experimenting with more PG. For now, I have cut down some of my 3mg juice to about half, using 100% VG base and have gone thru 2ml in less than an hour for clouds and experiments' sake. No headache, while it was there less than 2 hours ago. One thing to note is that it seems to work both ways - if i have a headache due to another reason, like having to work/concentrate on something for a long time, especially if it involved straining my eyes, taking a break and blowing some nice clouds will make it go away. Thoughts welcome.