Longevity and biohacking have become synonymous with the tech world, but an obsession with physical fitness wasn't always the norm in Silicon Valley, according to one CEO. Brian Chesky , the 44-year-old cofounder and CEO of Airbnb, said he felt like his interest in bodybuilding made him stand out when he first arrived in the late 2000s, and not in a good way. When asked about the latest peptide craze during a "TBPN" livestream on Wednesday, Chesky said he'd been slightly surprised to see the