In Smithsonian, Sarah Everts traces the deodorant business to Edna Murphey, a high school student from Cincinnati who around 1910 took an antiperspirant her surgeon father invented, meant for his sweaty hands in the operating room, and dabbed it in her armpits. Murphey dubbed the product Odorono and took it to market, but sales were slow. Then she connected with an ad copy writer who successfully made Americans, particularly women, worry that they might stink. From Smithsonian:
Young decided to present perspiration as a social faux pas that nobody would directly tell you was responsible for your unpopularity, but which they were happy to gossip behind your back about.
His advertisement in a 1919 edition of the Ladies Home Journal didn't beat around the bush. "Within the Curve of a Woman's arm. A frank discussion of a subject too often avoided," announced the headline above an image of an imminently romantic situation between a man and a woman.
Reading more like a lyrical public service announcement than an advert, Young continued:
A woman's arm! Poets have sung of it, great artists have painted its beauty. It should be the daintiest, sweetest thing in the world. And yet, unfortunately, it's isn't always.