When Jonathan Swerdlin tells you he pours his blood, sweat, and tears into his work, he means it more literally than most company leaders. Swerdlin is the CEO and co-founder of Function Health, a fast-growing personalized health testing platform that launched in 2023.
I, too, have given the company dozens of vials of my blood: When I found out about Function last year, I hadn’t been to the doctor in about a decade (a shameful confession for a health journalist). I was tired of what felt like a broken health-care system, but I knew I needed a check-up, so I signed up for Function, which costs $499 per year and includes two rounds of blood testing. First, you get an initial assessment with 160 lab tests, and then three to six months later, a follow-up including 60-plus retests to see how your numbers are changing. While no treatment regimen is provided based on results, clients receive personalized written insights from Function’s team of clinicians.
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“We, previous to this, knew less about our bodies than we knew about our cars. And Function has changed that,” Swerdlin says. “Nobody can say in 2025 that they have no way to understand what’s happening inside their body. By taking control today, you’re taking control of the future. Data over time—and it’s so important that it’s done over time—can help ensure you’re not missing anything that could materially impact your life.”
Function—which is backed by big-name investors like Matt Damon, Zac Efron, Pedro Pascal, and Jay Shetty—now has hundreds of thousands of paying members. It’s at the forefront of a growing trend of companies that aim to provide personalized insights to people tired of the traditional health care system. The idea is that, instead of waiting around for a doctor to figure out something is acutely wrong with you, you find out early enough to prevent it from becoming a bull-blown medical crisis.
TIME spoke to Swerdlin in May about how Function, one of the TIME100 Most Influential Companies of 2025, is expanding and why the health care industry is so overdue for innovation.
This interview has been condensed and edited for clarity.
What inspired you to start Function Health, and what keeps you motivated to run this company every day?
I had health issues when I was young, so I learned very early about the shortcomings of what health care can actually deliver. Fast forward, and my father beat prostate cancer, so I witnessed the power of medicine. I was caught between understanding the shortcomings of health care and the administration of it, and yet being in incredible admiration of the power of medicine.
That sparked my own interest in taking control of my health, and I spent years and tens of thousands of dollars cobbling together what is mostly an analog version of what Function delivers today. It became clear to me that it wasn’t a way to hack the system—it was actually the future of the way that people manage their lifelong health. It gave me so much agency and so much power that I felt like, I wish everybody could have this. I wish my whole family could have this; I wish my friends could have this, because I care about their life, and I want them to be able to benefit from this. Nobody knows what’s happening inside their body, yet the objective should be to need less health care and to have more life.
What do you think are the biggest challenges and shortcomings right now in the traditional health care system?
Health care is incomplete. What we expect to get from health care, it is unable to meet. Health care is not about helping you manage your lifelong health—it’s about solving problems. We’ve been missing any kind of platform or system that can help people manage their lifelong health outside of acute issues. And so what we need is a way to be on top of our heart, our liver, our kidneys, our thyroid, our hormones, and to always know what’s going on and what we can be doing, outside of pharmaceutical interventions, to be healthier.
What is a day in your life as CEO of Function Health like?
I have one focus, which is to do every single thing in my power to make sure our members can live 100 healthy years.
That’s my job every day, so what do I actually tangibly do? I spend my mornings, first, taking care of my health: I exercise, I eat well, I hydrate, I sleep, I do those things that one needs to do. Once I’ve taken care of my health, I’ll typically spend a lot of time understanding what’s new in the landscape, what kind of research has been coming out, and what’s the latest science. I have to keep on top of that every day. I also work with the team across all facets of the business, from how we tell our story, to where we are in engineering—as well as working diligently on expansion of the product.
Speaking of staying on top of the science: Do you have a favorite way to do that?
Well, I have a lot of help. I have a team that helps me do that; they surface and curate things that are coming up that are important in science and technology. But I also go digging around journals myself, and I work on keeping up with AI—which is moving at a breakneck pace. It’s almost a job unto itself.
You’ve previously remarked how cool it is that people finally care about health as a space in which to build a revolution. Has health care been pretty stagnant until now?
Health care has largely seen incremental changes in mostly institutional systems, and this generation is seeing exponential change. The greatest problem that we have is that 40% of premature deaths are preventable. All the suffering that’s attached to that—you can’t quantify it. People are suffering. It is the greatest problem that we can address. It’s a tangible problem, it’s solvable, it’s deeply impactful, and it sits inside of a tremendous market.
There’s $7 trillion spent across health and wellness. It’s always been a bespoke and artisanal service, and it’s moving from that to an engineered technology product model—which makes the ability to be healthy radically deflationary, and radically more accessible.
What’s the greatest challenge of running a company like Function Health?
The biggest challenge is that we’re racing against time to make sure that any person in the world gets access to this, and that means scaling up things that have previously not been scaled up.
Function recently acquired Ezra and introduced a $499 full-body MRI scan. Why are you excited about this, and what will it bring to the company?
Having a 360-degree perspective of your body has been difficult and very expensive. It takes a lot of time, traditionally, and it’s hard to find. With this acquisition, we’re introducing an FDA-cleared scan that AI brings from 60 minutes down to 22 minutes, and from $1,500 down to $499. By making it this affordable, this accessible, and this convenient and fast, we’re able to make [it] a thing that people do annually—rather than something available to only a select few.
People who get labs and scans done annually have, for the first time, a full 360-degree baseline of what’s happening inside their body so they can fully understand how it’s changing over time. You need to be able to detect changes, because changes are the best indicator of when something is going wrong.
You’ve also partnered with companies like Equinox, Thrive Global, and GRAIL. What makes a potential partner a good fit?
Our partners are committed to helping people achieve their best health. Equinox, for example, is clearly committed to making sure people are being healthy, because the whole purpose of their business is to get people to exercise and live a healthy lifestyle. So it’s a natural mission alignment.
The No. 1 thing is mission alignment, and then, does it actually make sense from a scale perspective? We think in the millions and billions. This is an 8 billion-person problem we’re solving.
Can you talk more about the way you prioritize accessibility–especially when good health care is out of reach for so many people?
I’m so passionate about this. Function is $1.37 per day. With our partnership with Quest Diagnostics, we’re available in over 2,200 locations around the country. It’s also very convenient. The actual time it takes for a blood draw and urine collection is 3 to 5 minutes. It is the smallest investment of time, and $1.37 per day, to be on top of your health.
We have people using Function in every state, including places like Mississippi and Alabama, where traditionally they weren’t really adopters and are known for having medical deserts. We’re creating health in what were previously medical deserts.
I get the sense that running Function feels more like a calling to you than work. Is that right?
Our life expectancy has flatlined. We are not getting healthier as a country. We can solve those problems—but upstream, we’re not actually getting to the root of the issue. I wake up in the morning with the clear directive to help people not suffer or die of preventable death, and that’s what drives me. That’s what gets me to work. Running any company is hard. I can’t imagine not fully, 100% believing in what you’re doing, and caring about it with every fiber of your being.
If you’re going to be an entrepreneur, you’re going to build something in the world, make sure it’s actually solving a problem you can care about for the rest of your life. And this is my life’s work.