When drunk, it adjust your carry-weight to what it thinks you should be at considering your level, maximum stamina and _LL_CarryPerLevel. When adding this mod to an existing save (or updating from a version < 0.4) and your character is above level 1, a potion called 'Elixir of Hidden Strength' is added to your inventory.
If you think that's too little or too much, you can change it via console: This is a tiny mod that, every time you level up, increases your carry weight by an additional 10 units. Playing as a mage? Tired of being stuck at the default carry weight? Then this is for you!