This is the original 1963 movie
starring Jerry Lewis, in color
Professor Julius Kelp (Lewis), is a nerdy, unkempt, buck-toothed, introverted, socially inept university professor who always incurs the wrath of the university administration by continually destroying the classroom laboratory. When a football-playing bully humiliates him, Kelp invents a serum that turns him into the extremely smooth, cool, and somewhat obnoxious girl-chasing hipster, Buddy Love.
This newfound persona gives him the confidence to pursue one of his students, Stella Purdy (Stella Stevens). At first she despises Love, but she finds herself strangely attracted to him. Buddy wows the crowd with his jazzy, breezy delivery and cool demeanor at the Purple Pit, a nightclub where the students hang out. He also mixes it up with the bartender, who is instructed on how to mix the latest drinks for the enigmatic entertainer.
The formula wears off at inopportune times, often to Kelp's embarrassment. He must rush back to his laboratory in the hopes that no one will discover his secret. Although Kelp knows that his alternate persona is an arrogant person, he cannot prevent himself from continually taking the formula as he enjoys the newfound attention that Love receives. Buddy performs at the annual student dance, and while on the dais, the formula starts to wear off.
In the end, his real identity is revealed during the prom, as the Love persona transforms to Kelp during a speech. He gives an impassioned plea that people must learn to like themselves before others can like them in return. He admits that he has learned a valuable lesson, and Purdy admits that she likes Kelp better than Love and they get married. Prompted by his formerly henpecked father's marketing of the formula, Kelp and Purdy decide to license the product and benefit from the profits.