elixir of destruction doesn't give you an effect of vampirism, it gives you the effect of restoring hp through your hits "but hokun izn't det tah saem?"
NO! What are you, a soy boy? Vampirism effects are gained via thirst for blood combos or elixirs of vampire. Just to explain you this I went out of my way and tested it and here are the results:
I hit (with extract of vampirism, no thirst for blood or any combo of such, no effects, nothing, just elixir) 620 and the amount of hp i gained was 355 but according to the elixir's description (which says 55% and my talent says 4% plus) i should've got somewhat around 341 because, you know, percentage of the elixir only is that much.
But I'M NOT DONE YET!
Here is the fun part: I should have gotten 365, because 59% of 258 is 152 and 59% of 362 is 213 and now I'm wondering why the hell i got 355 hp, where the hell is my 10 hp??!?!?!