The Regen Elixir is considerably underpowered for an interesting item. Normally, it gives you increased health regen in non-enemy locations (i.e. Commons), while also giving you normal health regeneration in areas with enemies (i.e. Unicorn Way).
I suggest the elixir to be reworked to give you full health/mana as soon as you either enter a new fight (similar to PVP), or after you finish a fight. If you die, you will also respawn will full health/mana.
Alternatively, you can also have an effect (perhaps on a new elixir, with a name such as "Refilling Elixir") that slowly refills your potions overtime. If this were to become a new elixir, it should have an increased duration over the normal elixirs (such as 6h for the "Mega" version).