melatonin

"I take 300 mcgs of melatonin which is like so a third of a gram a microgram milligram. I do a very tiny dose of melatonin. It's to offset the calcification that happens in my pineal gland."

Attribution: Bryan Johnson explicitly states he takes melatonin and explains his dosage and reasoning for using it

"You can use some of them use melatonin. You can also change when you eat."

Attribution: Tommy Wood mentions melatonin as one of the tools Formula 1 drivers use for managing jet lag

"Some people are taking melatonin. Some people are into the whole red light thing at night."

Attribution: James Nestor mentions melatonin as one of the interventions people are using for sleep improvement, alongside other methods