I have once tried to mix a simple, unflavoured, zero nic liquid at home. Just PG, VG and 10% purified water. Just a sort of "dooms day" experiment...
Later I discovered that in the lack of nicotine, adding 10% vodka instead of the purified water helps a little with the TH.
(And the final result, while not being even close to the liquids I buy, still beats smoking by a long shot. Imagine if I had some proper flavourings at hand at the time... come at me, new European TPD...!

)