I was on day two of a 10-day trip through South Australia. Back home in San Francisco, it was 2 a.m., but here in leaf-speckled Adelaide—a city in the depths of fall—it was 6:30 p.m. And while that time zone math might imply that I was a droopy-eyed, jet-lagged mess, I felt great.
This wasn’t a fluke. I wasn’t randomly spared by the jet lag gods. Nor was it sheer luck. I attributed my good cheer to a program called Flykitt, a combination of supplements, blue light–blocking glasses, and a customized app that promises to prevent jet lag for 93 percent of travelers.
What is FlyKitt and how did it come about?
FlyKitt was founded by CEO Andrew Herr. He has a background in health physics, immunology, and national security, which he parlayed into seven years working with the military—including Navy SEALs and fighter pilots—on performance issues, especially around sleep and circadian rhythms, which is a big concern for troops on the move. At the time, he was also working with nonmilitary clients who were having “personal, terrible experiences with jet lag,” he says.
“One day, this client came to me—he was a business executive flying from the East Coast [in the U.S.] to Korea regularly to close business deals,” Herr explains. The client was landing in Korea at 4 p.m., there was a big dinner that night, and the Korean team wanted to negotiate at 7 a.m. the next morning. “[My client] said, ‘We’re getting effing killed here. They’re using jet lag as a negotiating tool.’”
So Herr got to work. He took everything he’d learned while working with Navy SEALs and fighter pilots—particularly insights about how pressure changes during diving and flying cause inflammation—and combined it with the science around light therapy, meal timing, and supplements.
This first plan was fairly low-tech but served as a blueprint of what was to come: Herr typed his recommendations into a Word document—when to sleep, eat, spend time outside—and dropped the printed document off at his client’s office, along with a box of supplements. But it worked.
“ He emailed me from Seoul a couple days later,” Herr says. “ ‘Andrew, I just slept eight hours my first night. What did you do?’ That was the start of it.”
What exactly is jet lag?
To help me better understand why Flykitt works, I reached out to Dr. Jaime Zeitzer, a professor of psychiatry and behavioral sciences at Stanford University who has specialized in circadian rhythms for the past 30 years.
“ I always split jet lag into two parts,” Dr. Zeitzer says. “There’s one, which is a fundamental biological process. You’re traveling over time zones, and the external world that you’re trying to live in does not match the internal circadian clock.”
Dr. Zeitzer explains that the other part is not biological, but more situational: You have reduced oxygen when you’re flying, you eat at weird times, you’re possibly stressed out and anxious and “all those other things basically compound people’s experience of jet lag,” he says.
This isn’t earth-shattering news, but where science has really advanced around jet lag is the understanding of the circadian clock, which isn’t one clock but several. There’s a primary one in the brain, the suprachiasmatic nucleus (SCN), located in the hypothalamus, and Zeitzer says if you were to cut this out, “you have no more circadian rhythm.”
He continues: “ Then you also have clocks that are present in a lot of different organs. So your liver, your skin, your immune cells, your lungs, your heart. These all have clocks, which can be set by independent stimuli, but are really synchronized together through this central clock.”
The best way to think about all of this is that your circadian clocks are an orchestra. And “the SCN is playing the role of the conductor,” Zeitzer says. The primary way the SCN, our circadian conductor, synchronizes the other clocks is through light exposure.
Light exposure through our eyes is so critical to our clocks, in fact, that Dr. Zeitzer says that people with certain types of blindness, or who have their eyes removed, “move about one time zone per week.” Essentially, they live in a state of permanent jet lag.
So Flykitt’s focus on minimizing and maximizing light exposure depending on where you are along the journey fits the science. And then the timed food intake is key as well.
“If you adjust your food intake in the right way, you can adjust your gut clock faster than you can adjust your central clock,” he says. That helps in two ways: You’re eating more nutrient-rich foods that are beneficial to your body and reduce inflammation, “and you’re not disrupting your sleep because your brain’s not saying, ‘Oh, it’s dinnertime, even though it’s four o’clock in the morning,’ ” he adds.
How does Flykitt work?
For my trip, I purchased one Flykitt Core ($138), which is designed for a single round-trip, although travelers can also buy kits with enough supplies for three or five round-trip journeys. (For future trips, single round-trip refills sell for $69.)
The kit comes in a zippered canvas case and includes a three-page supplement packet with sections labeled “Advance” (vitamins B6 and B12), “Sustain” (fish oil and omega-3 oils), “Protect” (vitamin C), and “Mellow” (melatonin and magnesium). It also includes a QR code for the Flykitt app, an essential part of the plan, and a pair of blue light–blocking glasses.
The first thing I appreciated about Flykitt is that I didn’t need to do complicated math to try to adjust my sleeping and eating habits before I left for Australia. I simply plugged in my flight details, answered some questions about when I typically wake up and go to sleep, and the app calculated a program that would span the first several days of my trip, with the bulk of the action taking place on travel days.
“ The basic framework is: You’re a busy person,” Herr says. “I’m not going to ask you to do anything before the morning you leave. People are not going to do it.” He explains that the program tackles three key areas: managing inflammation from flying, strategically timing sleep and meals, and using light exposure to reset your internal clock.
“Usually during your flights, you’re going to sleep on the way towards your destination, but not too much and not too little,” he says. “We can give you a little bit less sleep than you could normally get, because the first negative effect of not sleeping is inflammation.”
Inflammation is a natural response, where your body releases white blood cells to support the injured or infected part of your body. Of course, you want your body to respond this way when you cut your finger or get sick, but it’s not helpful when flying and—in the studies Herr conducted with fighter pilots and divers—can lead to brain fog and other negative effects.
And while the medical community is still studying the connection between inflammation and flying, the science points to multiple effects, including digestive issues and the impact of jet lag on immune function. In fact, Herr is working on applying for grants that will allow the company to run a “full randomized-controlled, placebo-controlled trial.”
To reduce that inflammation, throughout my flight, the app sent me notifications about when to eat (recommending high-protein, low-carb foods and avoiding caffeine and alcohol), when to take the supplements (vitamin C and omega-3 fatty acids are part of the anti-inflammatory protocol), when to put on the blue light glasses (studies have shown that blue wavelengths disrupt sleep), and when to sleep and wake up.
The app also tracks the movement of your internal clock, with notifications about the gap between your home time zone and that of your destination, and it offers tips from a “circadian coach,” as well as details about your progress over time.
Depending on your program, as you move closer to your destination, the app will say it’s time for a “circadian reset”: a mix of sugar and methylated vitamin B. An hour before I landed, I mixed the circadian reset with 16 ounces of coffee.
Herr says the mix suppresses melatonin levels in your body and provides an insulin boost that helps reset your circadian clocks throughout your body, including your liver, gut, and brain.
“That’s going to power you through the rest of the day,” he says. “We’re going to keep managing the inflammation, keep managing circadian with our goal of landing you nicely in bed that night so you sleep a full night and you really are just on [the] destination [time] from your first night.”
While it might sound like a lot to manage, I found that the app’s reminders made me eat more healthily and more frequently than I usually do when traveling, choosing protein-rich snacks and meals and lots (and lots) of water over, say, a burger and a glass of wine.
I landed in Adelaide, Australia, in the morning feeling alert—that circadian reset is definitely an energy boost. While eventually I came down from the caffeine high and experienced the energy dips that accompany big time zone jumps, I stayed awake on that first day, took my supplements, and was ready for sleep by 9 p.m. that night. And just like Herr’s businessman, I slept a full and sound nine hours, which is unheard of for me. The next morning, I awoke feeling completely normal, as I did every day for the remainder of my trip.
I was pleasantly surprised but still skeptical. And yet I had the exact same experience on my return home 10 days later: I diligently followed the program, had one bumpy first day, and by the second day, was back to normal.
Is Flykitt worth it?
Flykitt is currently best for long-haul trips that cross multiple time zones. Herr says the company is about to release a domestic version that can help with three-hour time differences—which, as any coast-to-coast traveler can tell you, can be a sneaky energy suck. And in January 2025, Delta announced a partnership with Flykitt, the details of which will be revealed in the next year or so.
In the meantime, Herr has found that for 93 percent of travelers across all genders, races, and ages, the kit works. (There’s a reason pro athletes, including Olympians use it.) And if you’re among the 7 percent for whom it doesn’t work? “We have a money-back guarantee,” Herr says. “Because this is there to help people, and if it didn’t help you, then we shouldn’t get paid.”
There are, of course, other jet lag apps on the market. The supplements in the Flykitt are readily available for purchase. So do you need a $100-plus kit to ward off jet lag? Not necessarily. But I found that following the personalized program made me take much better care of myself before, during, and after my trip than I usually do—and that allowed me to enjoy my time, and my connections, so much more. And to me, that’s priceless.
