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What if you could slow aging and improve your biological function with a single 30-second shot? That’s the promise behind Minicircle, a gene therapy startup with lofty ambitions. As Founder and CEO Mac Davis put it recently on the One Day with Jon Bier podcast: “We want to extend the length and quality of human life.”
How the treatment works
Minicircle is best known for its therapy focused on the hormone follistatin, a naturally occurring protein that can increase muscle mass, improve recovery, and reduce inflammation. One injection, delivered into body fat, takes about 30 seconds and can last up to a year.
The treatments are not yet approved for use in the United States. So, patients must travel to countries such as Mexico and Honduras, where the company currently administers its gene therapy under medical supervision.
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New approaches to aging
Follistatin is not only being studied for performance enhancement but also for its potential to impact aging. Some animal studies have suggested that it could extend lifespan by over 30%. While much of the research is still in its early stages, there are signs that it could increase lean muscle mass, decrease body fat, and improve overall quality of life.
“I noticed a shift in how I felt — more aware, more present,” says Davis. “It wasn’t just physical; it was a sense of clarity, of being more connected to my body and the world around me.”
Davis believes that therapies like these represent a broader change in how we approach health: moving from symptom management to improving function proactively. “Gene therapy, at its core, offers the possibility to address issues before they become problems, focusing on enhancing function rather than simply treating dysfunction,” he explains.
Big-time backers
Minicircle doesn’t operate like most biotech companies. Davis didn’t go to business school or raise money through traditional channels. For a long time, no one would fund it.
“I didn’t come from a family of businesspeople,” he explains. “I didn’t have any financial backing. We tried to do a crowdfund. We raised $400. The guy asked for it back later.”
Then Sam Altman heard about it at a hotel bar and wrote a check. Peter Thiel was next. “I went there and I was like, hey, these are the vials. This is the idea. What do you think we should do with this?” Davis says. Thiel ended up talking for most of the meeting. He invested, too.
Minicircle used that support to build a small, highly specialized team. One of its lead scientists is a former NFL athlete who later earned a PhD in Molecular Medicine and Mechanisms of Disease. “He joined our clinical trial because he thought it would give him access to a next-generation gene therapy,” Davis says. “Then he really liked it and he joined the team.”
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The business of building the future
Minicircle’s work sits at the intersection of science, ethics, and entrepreneurship. Davis is learning as he goes.
Since then, the stakes have only grown. So has his appreciation for what matters most.
“The cost of a bad relationship is bigger than I ever knew,” he says. “And the upside of a great one is even bigger.”
With patients already seeing results and more therapies in the pipeline, the mission stays simple: extend human potential—ethically, safely, and accessibly.
“Longevity isn’t about living forever,” Davis says. “It’s about having the freedom to live the way you want, for as long as possible.”
What’s next
Minicircle’s next therapy targets a different hormone: Klotho. It helps prevent calcification in arteries, kidneys, and the brain. “It reduces improper calcium buildup,” Davis says. “And that’s huge for heart health and longevity.”
The therapy is currently being tested abroad, since gene therapy remains tightly regulated in the U.S. But the company plans to apply for FDA clinical use later this year.
“We’re applying for approval from the FDA to clinically administer this in the U.S. by the end of the year,” he says.
