Exstimulo Potion is one of the potions in Harry Potter: Wizards Unite.
This potion is extremely useful for giving that extra little edge in a trace or combat.
In a trace, it reduces the difficulty by a small amount, giving slightly more time on the spell timer and increasing the capture chance.
In a combat it boosts your damage by a small amount, but that could be the difference between killing a creature in 3 hits instead of 4.
See also