Good question, I would say yes. there are variations. Not sure if distilled water or similar is added to the mix, but I've had a 100% VG that pours nearly like water, then HHV's VG which is a good middle of the road and then another favorite vendor's where I nearly have to stand on, and then furiously jump up and down on the bottle to squeeze a single drop out of it! Perhaps someone can chime in as to whether adding a drop or two if water aids thick VG (to me hasn't been a problem with HHV) without loss of flavor?