The Nutty Professor (1996)

For Professor Sherman Klump, being the big man on campus wasn't all it's cracked up to be. His body was disproportionate. His family was dysfunctional. And his love life was disastrous. Having tried everything--diets, exercise and weight loss experts--in an unsuccessful attempt to shed some of his 400 pounds, Sherman Klump invents a revolutionary fat gene formula. Testing it on himself, he discovers he's no longer the man he used to be; in fact, he's only half the man he used to be. With one swig, the gentle, painfully shy academic is transformed into the swaggering Casanova, Buddy Love--an irresistible ladies' man who can talk his way out of any predicament. This new personality gives Sherman the confidence to pursue the chemistry department's beautiful new professor, Carla Purty. Indeed everything, to Sherman's utter amazement, is beyond his most perfect dreams--until he discovers that his long-lasting creation is actually an unstable substance that can wear off at any time.