Weaken is a low-level combat spell. When successfully cast on an enemy, their Strength level will be reduced by 5%. This effect cannot be stacked, meaning casting the spell multiple times will not lower the targets stats any further.

Casting Weaken requires 11 Magic. This spell costs 1 Body rune, 2 Earth runes, and 3 Water runes to cast. 21 experience is rewarded upon cast, regardless of whether or not the spell hits.