Andrew Thomas Weil is an American medical doctor who advocates for integrative medicine including the 4-7-8 breathing technique.

Timothy Francis Leary was an American psychologist and author known for his strong advocacy of psychedelic drugs. Evaluations of Leary are polarized, ranging from bold oracle to publicity hound. According to poet Allen Ginsberg, he was "a hero of American consciousness", and writer Tom Robbins called him a "brave neuronaut". During the 1960s and 1970s, Leary was arrested 36 times. President Richard Nixon called him "the most dangerous man in America".