Biohackers in Silicon Valley chase longer life—yet science remains unsettled

Tech titans and influencers are testing longevity regimens—from Bryan Johnson’s rapamycin experiments (which he stopped in 2024 due to skin infections, high glucose, and lipid changes) to various supplements, plasma infusions, growth hormone, and other compounds—often shared on social media. Researchers caution that these approaches lack robust human data and could be unsafe, describing a “shadow phase two” of self-experimentation that precedes rigorous clinical trials needed to prove any real benefit to healthspan or lifespan.