Josiah Zayner cursed under his breath as blood pooled under the thin skin of his subject’s leg. He checked for vital signs: no breathing. “I think I might have got the vein on that one accidentally.”

Zayner, who’d just administered an experimental injection, has a Ph.D. in biochemistry and biophysics from the University of Chicago, but to his patient such credentials were meaningless. The leg in question belonged to a Hyla cinerea, a small green tree frog not more than two inches long. The idea was to inject a genetic cocktail to make the frog’s muscles grow larger. A few hours later, the frog was back to its usually hoppy self, but it was touch-and-go for a while.

A year earlier, that gushing blood might very well have been Zayner’s own. He’s garnered attention and headlines for publicly self-administering experiments in a kind of performance-art-meets-biohacking theatric for a live audience and those watching on YouTube.

He once invited a reporter to witness a self-administered fecal implant to treat an irritable stomach. (The procedure entailed swallowing a pill filled with a friend’s poop.) He attempted to genetically modify his skin cells to turn a patch a darker color. And, as he did to the frog, he injected himself with a DNA mix in a bid to bulk up his muscles. Should one feel inspired to recreate some of Zayner’s antics at home, he’ll sell you the tools to do so on his company website, The Odin.

Is this Silicon Valley’s answer to vaudeville? Or is Zayner at the forefront of a movement in which biotech is trickling down to garage entrepreneurs, in the same way that democratized computer and coding technology let curious tinkerers build Silicon Valley?

For now, Zayner has turned his attention to critters, after the U.S. Food and Drug Administration issued a warning on the sale of gene-therapy products for DIY human use.

For $499, anyone can order a kit containing six frogs, cages, food, and all the materials necessary to replicate Zayner’s frog muscle therapy at home. Zayner believes the experiment is legal: The Animal Welfare Act exempts “cold-blooded” animals, including frogs, which the FDA regards as a “minor” species anyway.

Maybe not minor enough, though, after their DNA has been altered. “The FDA does not regulate the kits you mention; however, the agency does regulate animals that contain intentionally altered genomic DNA,” an FDA spokesperson says.

The kits are the fruit of six months of experiments at Zayner’s West Oakland, Calif., laboratory, which houses dozens upon dozens of tree frogs (Zayner isn’t sure exactly how many). The lab is a sophisticated, albeit less-than-sterile, space with an office fridge stocked with Red Bull and coconut water. His three full-time employees tap away on laptops filling orders, answering customer inquiries, and helping design instruction materials. A big-screen TV livestreams a computer game competition. His younger brother Micah lives upstairs.

Despite his body piercings and disdain for the slow pace of institutional science, Zayner has garnered a surprising amount of respect from the establishment. He’s regularly asked to speak at conferences. Last year, the famous Harvard University geneticist George Church signed on as an adviser to Zayner’s company. Church believes DIY bio is part of a long evolution of human activity that’s culminated with rapid advancements in scientific fields such as genetics.

“DIY bio is a modern extension of ancient practices like breeding plants, animals, [and] microbes,” Church says.

Zayner says he wants to democratize science, helping people understand today’s technologies and make the most of what modern medicine has to offer. He can veer toward grandiosity, having once prophesied a world where people would cure whatever ails them through their own genetic experimentation, or toy around with DNA recreationally.

“I don’t want to say I want to, like, take down the FDA, but we need to figure out a new model that works,” Zayner says, right before injecting the frogs with their first round of follistatin. “There are a ton of people dying and suffering that don’t have access to the drugs they need. Something is going to have to break eventually, right? I don’t know when, and I don’t know what’s going to cause it, but maybe we can help push things forward.”

After Zayner’s first public injection, a young, HIV-positive software engineer gave himself a vaccine meant to suppress HIV while streaming the endeavor on Facebook Live.

In February, Aaron Traywick, chief executive officer of a biotech startup developing its own treatments outside the purview of regulators, announced onstage at a body-hacking conference that he had herpes, then took off his pants and injected his thigh with a “gene therapy” he claimed could both prevent and cure the virus. (Traywick’s death a few months later was unrelated to that or any DIY procedure; he drowned in a sensory-deprivation tank with ketamine in his system.)

“FDA is aware that gene therapy products intended for self-administration and do-it-yourself kits to produce gene therapies for self-administration are being made available to the public. The sale of these products is against the law. FDA is concerned about the safety risks involved,” the agency said in the warning.

Thus the pivot to amphibians.

Zayner says the evidence suggests they will work well for the tests. In one experiment he conducted, 12 frogs were given a different DNA mixture containing IGF-1, a human growth factor he hoped would make the frogs grow bigger than usual. After several injections and a few weeks, their weight on average increased by about 23 percent. Six untreated frogs gained hardly any weight at all. Tests revealed that the DNA was in the frog’s liver, a sign the animal’s body was reproducing it.

Could Zayner’s frog experiments ever translate into safe DIY gene therapies for humans? Medical experts aren’t yet convinced.

“The idea that a homebrew guy could inject a frog and deduce whether the same therapy would work in a person” is a stretch, says Stanford bioethicist Hank Greely. “If this is a step toward successful DIY gene therapy, it is a very small step on a very long path.”