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Hey, Google: Remember that stem cell problem you tried to fix in 2019 by banning clinics from advertising unproven therapies on your platform?

The solution didn’t last. Clinics have adapted, but you haven’t, leading to widespread use of your search platform by clinics to pitch risky cell injections.

In response to criticism that Google ads for unproven medical offerings were doing harm, the firm adopted a policy in 2019 banning stem cell clinic advertising on its platform. This positive step was part of a larger move against ads selling unproven therapies. Many of the culprits were clinics touting stem cells as treatments for everything from Alzheimer’s to stroke.


After the ban was implemented, people searching for “stem cells for COPD” or “stem cells for neuropathy,” to cite just two examples, would no longer see a slew of ads for clinics offering risky, unproven therapies above the Google search results. That worked for a while. But stem cell clinics and others promoting unproven therapies now effectively game Google’s search engine to get new customers.

For example, while stem cell clinics may no longer rely on Google ads to hoist themselves to the top of a search results page, some clinics still dominate large swaths of Google search results related to stem cells. In this way, the company is inadvertently sending many people to these clinics to get risky, unproven injections that generally lack FDA approval and, in my view, have no solid scientific or medical foundation.


This weakness in Google search has become a public health issue.

The FDA has been largely ineffective at regulating stem cell clinics. Sure, it has issued warnings to a few. But hundreds of these clinics operate in the U.S., with many more worldwide. I hope the FDA becomes more aggressive in regulating the U.S. clinics — and there are signs it might in the future — but in the meantime Google has a responsibility to tackle its side of the problem.

What’s the issue more specifically?

For many of the most common stem-cell-related searches, Google often spits out top hits listing either websites for stem cell clinics or promotional sites that direct potential customers back to the clinics. That means if you want to know more about stem cells via Google, the search engine will often point you to the profiteering clinics as the supposed authorities.

Those troubling clinics often outrank the National Institutes of Health, the Food and Drug Administration, universities, and other authoritative sites like the Mayo Clinic in Google search results.

Take the two examples I mentioned earlier: “stem cells for neuropathy” and “stem cells for COPD.” As I write this, the number one result in each case is a stem cell clinic, which outranks the American Academy of Neurology, the American Lung Association, the NIH, and other truly authoritative sites. In the case of the neuropathy search, almost every result on the first page is a for-profit clinic selling unproven stem cell injections.

In this way, Google is putting vulnerable people at serious risk. At the very least, thousands of people are losing large amounts of money on generally useless “treatments.” But it’s more than that. We’ve learned in recent years just how big a health gamble going to stem cell clinics can be with reports of patients being blinded, developing the life-threatening blood infection known as sepsis, or having other serious side effects. In rare cases, people have died.

The stem cell problem with Google — and how it handles searches related to other unproven therapies — ties back into search engine optimization (SEO). Put simply, SEO basically designs a website to perform in the way that Google thinks is best. The websites with the top SEO will almost always rank highest in Google search results, even if they are selling unproven biomedical offerings.

That has to change.

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As it now stands, anyone trying to pitch an unproven therapy in theory just has to pump enough money into SEO and Google will usually rank them highly or at the very top in search results, even if the supposed treatment is bogus or dangerous. Google search has effectively become a form of advertising for sketchy health care. In the worst cases, sites ranking the highest with Google may even be selling non-FDA-approved stem cell therapies that are illegal in the U.S.

Google has known about this problem at least since the spring of 2021, but nothing obvious has changed. At that time, I was able to meet with representatives from Google about my concerns. We had an interesting talk, but I didn’t get very far advocating for change.

One thing I did learn is that there are at least two sides to Google, and they don’t necessarily connect well with each other. Policy people are on one side. They’re the ones responsible for the ad ban on the stem cell clinics. The search team is on the other side, and they have a very different perspective on things.

The disconnect between the two is exemplified by the fact that many of the same stem cell clinics now barred from advertising on Google are the same ones whose websites are killing it with Google search and in that way presumably driving loads of customers to their profitable but risky clinics.

The problem related to stem cell clinics is just the tip of the iceberg. What I’ve been watching with stem cells is going on much more broadly with health-care-related searches in Google. It’s fairly easy to find examples of outright snake oil ranking number one in Google search. For instance, Goop’s page promoting jade eggs ranks best for a search for jade eggs and above the relevant information page of the Cleveland Clinic, and a search for energy healing delivers a page from a practitioner of energy healing above pages debunking the practice.

Those in charge of Google search might argue that’s the way it should be. Perhaps they’d say that hopeful searchers want to be directed to purveyors of unproven health care more than to factual information, as reflected in the patterns of what searchers click on. However, the search engine has a greater responsibility to public health than to follow whatever health care hype is popular at any one particular time with the public.

The bottom line is that when it comes to health and health care, Google search is not as logical or safe as many of us might assume.

I believe that part of what is going on is that Google views its search engine as almost sacred. As a result, perhaps it doesn’t want to factor in too many ethical or public safety considerations into how its search engine works.

At this point, however, Google can’t afford to view its search engine in that hallowed way when it comes to health care. There are just too many websites out there purveying unproven — and even risky — treatments that Google nonetheless ranks highly.

Is this a solvable problem? Can Google determine what is an unproven medical offering for sale on a website? Could the company distinguish between ongoing clinical research and marketing unproven therapies? Such things could be challenging, but I’m confident Google can figure it all out.

In non-health-care areas, like guides to making weapons of mass destruction or certain kinds of porn, Google already takes into consideration whether websites have questionable or illegal content or products for sale. Such websites generally don’t turn up in search results. Making searches related to health care safer should be no less important.

Google’s continuing stem cell problem is emblematic of a serious, broader problem with unproven biomedical offerings the company needs to address. The solution seems obvious: Selling an unproven treatment must become a consistent, major negative SEO ranking factor incorporated into the company’s algorithms.

Otherwise, Google, you’re continuing to enable those who sell unproven and sometimes even dangerous medical products and putting the public at risk.

Paul Knoepfler is a professor at the University of California Davis School of Medicine whose research focuses on stem cells and cancer. He writes about ethics, policy, and other matters on his blog, The Niche. Ads on The Niche are limited to reagents for stem cell researchers, not therapy for patients.

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