“Come watch me trip balls,” declared Bryan Johnson, the “Don’t Die” longevity entrepreneur, on X a couple days before he livestreamed himself consuming a high dose of psychedelic mushrooms at a psilocybin center in Oregon on Sunday.

It marked the second act of his stunty new investigation into whether using psilocybin can improve almost 250 wellness biomarkers including various measures of brain connectivity, cortisol levels and testosterone.

“There’s a potential for psychedelics to play a more important role in all of our lives, and wouldn’t it be amazing if it was also a longevity therapy,” Johnson proclaimed on the stream. Prior to consuming the shrooms Sunday—which has been legal at licensed facilities in Oregon since 2023—Johnson measured his brain activity with a $50,000 helmet produced by Kernel, a neuroimaging company founded by the 48-year-old. He also took saliva samples and temperature readings. (After his November trip, he shared a lot of information about the state of his erections, but more on that later.)

Then he drank more than five grams of powdered mushrooms mixed with lemon juice, for extra potency. Johnson grimaced, and a bizarre new era of live celebrity psychedelic exhibitionism was born—one that is arguably counter to the introspective nature of the drug. The five...