A Tokyo startup called TIME TRAVELER thinks the antiaging answer was sitting in the vegetable drawer all along.
Part of a ten-part series profiling each of the $101 million XPRIZE Healthspan competition’s Milestone 2 Awardees. Across the series, Longevity.Technology examines the science behind each team’s approach, the trial data supporting it and what stands between them and the competition’s final phase.
The idea started, oddly enough, with mayonnaise. During the COVID pandemic, Rieko Akiyama kept noticing how much of the conversation in science had shifted away from animal-derived materials, which come loaded with regulatory hurdles, and toward plant-based alternatives, the same shift that was already reshaping food products on supermarket shelves. She wondered whether that logic could apply somewhere nobody had really tried it: longevity medicine.
That question became the founding idea behind TIME TRAVELER, a biotech startup Akiyama launched in 2024, built on research from her father, Tetsu Akiyama, a tumor biology researcher at the University of Tokyo. Today, the company is one of just 10 teams worldwide to make the finalist round of XPRIZE Healthspan, the $101 million, seven-year competition designed to separate legitimate longevity science from the noise. And its leading idea, as it turns out, involves parsley [1].
What exosomes are, and why plants change the equation
To understand what TIME TRAVELER is actually testing, it helps to know what an exosome is. Cells constantly release tiny bubbles called exosomes, formed when the cell membrane folds inward and pinches off, carrying a mix of enzymes, fats and genetic material out into the body. Human-derived exosomes have become an increasingly popular ingredient in antiaging beauty products across Japan and Asia, but they’d never really been tested rigorously for longevity effects, and sourcing them at scale from human or animal tissue comes with real safety and regulatory baggage.
Tomoatsu Hayashi, a project assistant professor at the University of Tokyo and TIME TRAVELER’s co-CEO, took on the job of figuring out whether plants could do the same job more safely. His team screened more than 140 species of edible plants and algae, including 95% of everything that grows in Japan, hunting for exosomes that behaved like the human version. Nobody knew if that was even possible going in.
“We didn’t know if plant exosomes would have the same effect in human cells,” Hayashi told TIME. Starting with mice, then human cells, his team found that plant exosomes behaved remarkably similarly to human-derived ones, and out of everything they tested, parsley came out on top [2].
From the lab bench to a sleeping supplement
The results so far are early but real. In mice, parsley-derived exosomes lowered inflammatory markers linked to many of the cellular processes behind aging, and mice given the exosomes in their drinking water held onto more muscle strength than similarly aged mice that didn’t get them, measured by something researchers actually use: how long a mouse can hang onto a wire cage before letting go. Sounds almost too simple, but it’s a standard test of grip strength and muscle endurance in aging research.
The human side of the story is a small pilot, 40 people taking a daily supplement pill, but the direction matched the mouse data: lower inflammation markers, along with anecdotal reports of sleeping more consistently and feeling more energetic through the day. That combination of animal and human data was enough to earn TIME TRAVELER a spot in XPRIZE’s next testing phase, where the team will run a larger trial evaluating muscle function, walking, leg strength, cognitive performance and inflammatory blood markers.
Why this matters beyond one Tokyo lab
TIME TRAVELER isn’t the only team betting on exosomes. A second University of Tokyo group in the same XPRIZE cohort is chasing the same biology from a completely different angle, engineering stem-cell-derived “super exosomes” designed to home in on aging cells directly. That two teams from the same city, working the same underlying science, landed on such different strategies says something about how open this particular question still is.
What makes TIME TRAVELER’s approach worth watching isn’t just the parsley headline; it’s the safety and scalability argument underneath it. Plant sources sidestep the heavy regulatory scrutiny that comes with anything animal-derived in science, and edible plants are, by definition, things people already know how to grow and consume safely at scale.
If a compound this ordinary turns out to reliably lower inflammation and protect muscle function in humans the way it has in mice so far, it would be a strikingly low-tech answer to one of longevity science’s most expensive problems: how to deliver antiaging biology to millions of people without a supply chain built on human or animal tissue. The bigger trial now underway will be the real test of whether that promise holds up outside a petri dish.
Photograph courtesy of TIME TRAVELLER
[1] https://www.ttraveler.jp/news/287
[2] https://time.com/article/2026/08/21/xprize-healthspan-best-longevity-ideas-top-10/
