Conditions to using 2 special potions at once?

It says in the description of various potions that if you're an alchemist you can use two of them at once, but it says "a potion of this type is already in effect" (or something like that) when i try to use a second one as a level 1 alchemist. Do i need to be a certain level to activate two of them?

The level to craft them, I think.

Seriously? What a pain in the ass. I guess i have to hurry and max willpower so i can be a level 10 alchemist for the rest of my career. >_>

Thanks!