Macular degeneration is the most common cause of vision loss among the elderly. But for some people with the disease, a shot of stem cells to the peeper was all they needed to see again. For others, treatment left them permanently blind. What gives? Stem cell treatments like the one described above—happening every day in 600 clinics across the US—are not approved by the FDA, and in fact have never been tested in a clinical trial.

Eyes aren’t the only organ getting stabbed full of stem cells. Around the country, more doctors are marketing the therapy to treat everything from diabetes to asthma to erectile dysfunction. The procedure usually involves sucking out some of a patient's fat tissue with a liposuction needle, isolating their stem cells, and reinjecting them back into the place in their body that needs most healing. But because these are living tissues unique to every individual, results may vary. Advocates of the therapy say that’s just the cost of doing cutting-edge medicine. Except, any proof they have that it is effective comes from data collected on patients who pay thousands of dollars for the treatment. Usually people pay money for medicine after there’s proof it works. In the last few years, some of these stem cell clinicians have begun posting large-scale studies on a government-run website called ClinicalTrials.gov, even though they're often not up to medical research standards or even in compliance with federal regulations. This allows them to masquerade their pay-to-participate studies as legit science.

According to a paper published today by the University of Minnesota, US companies have successfully registered 18 “patient-sponsored” stem cell studies on that publicly funded website. Only 7 of them disclose that patients pay their own way. None of them list the costs, which can range from $5,000 to $15,000 a treatment, outright. And none of them are actual clinical trials in the randomized, blinded, gold-standard sense of the phrase. Instead, they’re observational studies, based mostly on quality of life questionnaires that ask if you’ve had any adverse reactions to the procedure.

Leigh Turner, the bioethicist who penned today’s perspective and who has become somewhat of a watchdog in the ballooning stem cell clinic industry, says this amounts to hijacking a public good and repurposing it into a free marketing tool. “They don’t have to pay for ads on television, people just come to them because it’s this trusted national resource,” he says. “It’s all meant to suggest a seal of approval from the federal government. And that’s what’s so dangerously misleading, because it doesn’t mean that all. It just means someone filled out a form and pressed a button.”

Following the passing of the Food and Drug Administration Modernization Act of 1997, the National Library of Medicine established ClinicalTrials.gov to serve as a source of information about publicly and privately supported clinical trials for patients, their families and caregivers, doctors and nurses, and the public. But the NIH doesn’t independently verify the scientific validity of any trials posted to the site beyond a limited quality control review. That doesn’t really include things like sound study design, compliance with current regulations, or ethical guidelines. In fact, the process is largely automated, and relies almost entirely on the honor system.

NIH said in a statement that it is continuing to evaluate ways to improve its outreach to make sure that trial participants understand potential risks and benefits. That included adding a prominent disclaimer on the ClinicalTrials.gov homepage in March 2017, stating: “Listing of a study on this site does not reflect endorsement by the National Institutes of Health. Talk with a trusted healthcare professional before volunteering for a study.”