Pheromone Holic

Hyunwoo is basically seen as a loser. His freshman year of college was awful, and his sophomore year isn't looking much better. But things get strange when he saves the life of an old snake-oil salesman on his way home. As a token of gratitude, the old man offers Hyunwoo a special potion promised to fulfill all his wishes.

To top it off, Hyunwoo finds himself living in an apartment building surrounded by attractive women, including his college crush. With all this going on, Hyunwoo's got his work cut out for him.