Iterable CEO Justin Zhu was recently fired for "micro-dosing" LSD, a psychedelic drug, to improve his focus, he told Bloomberg last week. Micro-dosing, or taking small amounts of psychedelic substances, has gained popularity in recent years among entrepreneurs as a way to boost their creativity. Plenty of other CEOs and founders who want to improve productivity and prevent burn out turn to so-called "biohacks," a broad term that encompasses everything from enzyme injections to fasting days. Here are seven biohacks executives have used, along with the science — or lack of it — that backs them up. Winston Ibrahim, CEO...