As far as I'm aware there is no ban on vaping in Turkey, but the sale or promotion of the actual product and the liquids requires a licence which is nigh on impossible to obtain. That said, folks I know who vape don't appear to have much of a problem either using their gadget or obtaining supplies.
The official line is similar to the alcohol free beer, in that it may encourage folks to get hooked on nicotine.
The fairly well known alternative view is that the tobacco companies lobbied against the vaping sector and were successful. We all know what that means...
Wonder how many shoeboxes it took

JF