Silicon Valley’s newest body hack: Caffeine pills before bedtime

This summer, Isaiah Granet, the 24-year-old founder and CEO of Bland AI, a voice-agent startup, was busy finalizing a $16 million Series A round. “I was falling asleep at 1 or 2 a.m., and then up by 7 or 8,” he recounted. To keep up with his hectic schedule, he relied heavily on caffeine — about 700 mg a day in cold brew. “It’s very unhealthy,” he admitted, but it felt necessary. “Waking up every day is a chore. … I’m exhausted and just want to go back to sleep.” 

Then he discovered Zest, a time-delayed caffeine capsule touted as the “world’s first wake-up pill.” Intrigued by its promise and the fact that its creator, Jason Jin, came from the sleep science world, Granet reached out to Jin to ask if he could be a beta-tester. Worst-case scenario, he figured, he wouldn’t fall asleep after taking the supplement and would just work late. “I was pretty primed to be a guinea pig,” he said. 

On his first night on Zest, Granet swallowed the pill around 1 a.m., then headed off to bed. Seven hours later, his eyes opened. “It was pretty smooth,” he said. “Like you’re gently exiting sleep by driving down a ramp instead of jolting awake.” After years of groggy mornings, filled with “40 alarms that go off every five minutes,” this felt like a revelation.

Many people — myself included — struggle with getting out of bed in the morning. There’s a name for this problem: sleep inertia, described by scientists as “grogginess and impaired vigilance immediately upon awakening.” Grogginess is exacerbated by lack of sleep, which affects around 35% of Bay Area residents.

For some in Silicon Valley, being sleep-deprived is a point of pride, in the mode of Marissa Mayer and Elon Musk, who supposedly get by on four to six hours of shut-eye. The longtime solution to sleep inertia has been to mainline caffeine in the morning. But now, some sleep hackers are switching to time-delayed caffeine pills taken at night.

Zest, currently available to select beta-testers, is being bootstrapped by Jin, the former CEO of Crescent Health, a sleep coaching startup that was acquired by employee health platform BetterUp. “Even people with optimal sleep often wake up feeling not super refreshed,” said Jin. “That means for the first 30 minutes of the day, you’re still suffering.” 

He whipped up his first delayed-caffeine batch of Zest in his kitchen but overestimated the time-delay formulation and woke up at 4 a.m., “super wired.” He partnered with a lab and pharmaceutical manufacturer to refine the formula and ensure a consistent seven-hour-delay caffeine-release mechanism. Each Zest capsule now contains 80 mg of caffeine, plus zinc and B vitamins — all FDA-approved ingredients. There were 35 people in Jin’s first test group and 60 in his second, primarily Bay Area tech workers. A commercial launch is slated for late December, he said.

Zest isn’t the first company to offer time-released hits of caffeine. B Sync On, launched in 2021 in Zurich, is priced at $20 for 20 doses and promises similar benefits for “morning grouchiness,” but it doesn’t ship to the U.S. 

Other variants are marketed as fasting aids for religious worshippers, like Orthodox Jews, who want to have energy on holy days. Options include Easyfast and Eichlers Magic Pill Fasting Aid, priced at $12 for one 12-hour-delayed dose. On Amazon, I found amUpandGo and Rise-N-Shine Wake up on Time pills, which offered various blends of time-delayed caffeine and vitamins. 

But are any of these supplements backed by legitimate science? A 2021 study by the B Sync folk published in Nature analyzed the effect of time-delayed nighttime caffeine on intentionally sleep-deprived men and found “improved behavioral, cognitive, emotional, and physical levels.”

Conceptually, these pills could be considered a super-extended “nappuccino,” said Cassie Hilditch, a researcher at the Fatigue Countermeasures Laboratory at San Jose State University, referring to the trend of having a cup of coffee before a 20-minute catnap. Bedtime caffeine pills are “unlikely to be dangerous,” she said; however, the only studies to date have been on healthy young men. “It’s a leap to go from ‘it works for this subset’ to ‘it works for everyone,’” she said. “We all metabolize caffeine differently.” 

Justin Zheng, a 23-year-old engineer at a gaming startup who lives in Inner Richmond, was excited to beta-test Zest. “Of all the [supplements] I could be taking, caffeine is a pretty chill one,” he said. “Waking up kind of sucks, you know.”

Zheng avoids coffee due to stomach issues but said he regularly chugs energy drinks for a pick-me-up. He generally swallows his Zest capsule around 1 a.m., and it kicks in around 8 a.m. “I wake up and I’m ready to go,” he said. “Like, I get ready, I do a crossword, I go to the gym …” 

His supply ran out quickly, as many of his friends wanted to try it. There’s a huge difference when he goes without Zest, he said. “I’m tired, I feel lazy, I scroll Instagram, I don’t want to work out.” The one person in his life not interested: his caffeine-avoidant girlfriend. Plus: “She just graduated and doesn’t have a job, so she doesn’t have to get up.”

Azure Grant, a neuroscientist at People Science, which runs decentralized clinical trials, said delayed-release caffeine is an intriguing proposition. Caffeine has a proven effect on alertness and is a safe, well-understood compound. However, everyone processes it at a different rate, and its half-life can range from a few hours to 10, she noted. Grant, who’s considering partnering with Jin on a study, said Zest’s current format “is very safe.”

Some people, however, aren’t willing to wager on the possibility of poor sleep or pre-dawn wakeups. Eric Jung, cofounder of So Brief, a San Francisco startup for AI-powered book summaries, received five Zest capsules from Jin but chose not to take them. “I have sleep apnea and need nine hours of sleep,” he said. “Zest’s seven-hour release doesn’t make sense for me.” He’d be open to trying a longer-release version, however.

Once people — including me — have gotten over their initial shock around bedtime caffeine, they acknowledge that there’s a certain logic to it. “When am I getting mine?” asked Gadi Borovich, a venture capitalist at Antigravity Capital, on X. “Ozempic but for needing less sleep. Who’s building this,” posted Oliver Hsu, a partner at Andreessen Horowitz.

Zest isn’t perfect, admitted Granet; when he doesn’t eat enough before bed, he wakes up too early. Still, this “wake-up time bomb” has been transformative, he said: “Zest has changed my attitude to waking up. I keep begging Jason for refills.”