If you listen to the internets most famous medical influencers medicine is finally getting an upgrade.
According to Peter Attia in the last century or so we’ve blown past medicine 1.0, 2.0 and are deeply ensconced in what he calls Medicine 3.0. Just like any tech bubble, some internet-famous doctors are heralding yet another whole-step improvement before we’ve even had a chance to take a breath: Medicine 4.0.
These charlatans have led us to believe that scientific revolutions are as straightforward as a software update for your iPhone. But actual science is slow. It’s a twisting path of decades-long evidence, hypothesis testing, and clinical trials in actual humans to see if new approaches actually lead to better outcomes.
That hasn’t stopped a battalion of profiteers from claiming they’ve unlocked “medical secrets” that the rest of the world is missing.
Over the last few weeks, I’ve been exposing the bad actors in the field of regenerative medicine who sling stem cells, peptides, and exosomes like they are divine ambrosia. I am still deep in my research on Adeel Khan’s “clinic to the stars”—the doctor who likely gave functional medicine icon Mark Hyman a life-threatening case of sepsis.
It leaves us with one burning question: Is regenerative medicine a total false promise, or is there real science buried under the grift?
To answer that, I’m joined today by Matt Kaeberlein.
Matt is a biogerontologist at the University of Washington and a leading expert in aging and longevity. He’s also a veteran whistleblower who famously exposed the impossible claims regarding David Sinclair’s results on reversing dog aging.
You might remember Matt from our previous interview a few years back. To put it mildly, we’ve had our share of contentious exchanges regarding the philosophical basis of longevity medicine. We disagree on a lot—but I have never doubted his scientific integrity. We are both able to look at the same bed of evidence and make rational assessments of what that data actually means.
In this conversation, we separate the “divine ambrosia” from the hard data.
Matt Kaeberlein: Thanks, Scott. It’s really a pleasure to be back. And I’ve got to say, I’m really enjoying your content. I think you bring a ton of value to this space. I would also be interested, maybe on a future opportunity, to sit down and figure out what we actually disagree on. I suspect we agree on a lot more than we disagree on. Getting people together who are thoughtful and coming at this from the perspective of wanting to get the truth out there leads to important conversations.
The following is a transcript from our conversation that was made with the assistance of AI. Please refer to the original interview if there are discrepancies.
Scott Carney: Yeah, absolutely. In fact, one of the problems in the world right now is people think that they’re always right and just sit in their camps. What we actually need to do is read the actual evidence that’s out there and have reasonable conversations on it. Anyway, thanks for being here. My first question is really basic: What is regenerative medicine?
Matt Kaeberlein: I would characterize regenerative medicine as a science-based approach to restore lost function in cells, tissues, and organs by repairing damage that has accumulated. In that way, it’s just a different way of approaching functional decline and disease.
The approaches can include cell-based therapies—which is where stem cells and immune-modulating approaches come from—drugs that harness the body’s own repair pathways, or tissue engineering. It all falls under this idea of repair. You can contrast that with traditional medicine, which is largely reactive—a Band-Aid approach after damage has happened—or proactive healthcare, which is about preventing the damage before it happens. Regenerative medicine is the repair of damage. From that perspective, it’s absolutely a valid approach with real science. However, as is often the case, opportunistic people get way ahead of the science and try to take advantage of people who want access to these kinds of approaches.
Scott Carney: There’s always this tension between what you hope something will do and what it can actually do. That’s where marketing sneaks in and causes damage. Let’s talk about stem cells specifically. For the last 20 years, they’ve been touted as being able to regenerate just about any tissue. That is exciting stuff, but the advances seem stuck. How much evidence have we seen in clinical literature for their effectiveness?
Matt Kaeberlein: It’s fair to say that while there is exciting science here, the field has failed to deliver on early promises. It’s important to separate what’s done in the laboratory from what’s done in the clinic. In rodents and other mammals, stem cells look extremely promising. There have been hundreds of studies showing benefit for many different diseases.
As is almost always the case, when we move into humans, it gets complicated. Sometimes the biology doesn’t work the same way. There are several reasons why it feels like stem cells have stagnated. Part of it is the media amplifying results and scientists hyping their own work to build false expectations. Some of it is the regulatory environment; in the early 2000s, there were federal bans on basic research on certain types of stem cells.
Clinical trials for regenerative therapies are also hard because there are significant risks. Because these therapies promote growth and repair, they can also promote cancer. We have to be very careful. Finally, stem cell therapies don’t work very well in older animals or people. The aged biological environment—where there is more inflammation—makes it more challenging for stem cells to do their work. Scientists who study stem cells haven’t always appreciated that you have to do things differently for older humans. I would frame it as a field with potential, but it’s unlikely to be the cure-all for every ailment.
Scott Carney: It’s interesting—when I was writing my book The Red Market about organ trafficking, I visited stem cell clinics in India around 2011. They were offering treatments to medical tourists. Sometimes you’d see amazing results, like an angiogram showing vasculature regenerating, but when there were no results, that wasn’t reported at all. There was always this hype that we’d have great stem cell treatments in two or three years, but we didn’t see that.
Right now, there’s excitement about breakthroughs involving something called “Muse” stem cells from a Japanese researcher named Mari Dezawa. Are they really a breakthrough?
Matt Kaeberlein: From a basic science perspective, they are. MUSE stands for Multi-lineage differentiating Stress Enduring mesenchymal stem cells. Dezawa took a mixed population of stem cells and selected for cells that are particularly resistant to stress, like low oxygen or nutrient stress. These cells have interesting properties: they are more pluripotent (can turn into more cell types), they have a lower cancer risk (specifically for teratomas), and they seem better at moving to sites of injury.
However, there is very little clinical evidence yet that they will live up to that promise in people. In Japan, they received “conditional approval.” This means they can be used in clinics legally within very narrow indications—not because they’ve been proven to work, but because they have sufficient short-term safety. It allows companies to go to market and gather proof of efficacy while selling the treatment. People misinterpret that as proof that it works. It’s promising, but very early. It will likely be a step-breakthrough for specific indications 10 years from now, but it won’t be a magic pill that makes everyone younger.
Scott Carney: This leads to a gap. Dezawa stem cells are like the “Ferrari” of stem cell clinics right now. But as you mentioned, there’s always a new shiny object.
Matt Kaeberlein: I’ve been in this space long enough to know that next week it will be something else. Opportunistic people grab the next shiny object because they can sell it. Unfortunately, many medical professionals in this space aren’t strong critical thinkers and they actually believe the hype, forgetting they’ve done this five or six times before.
Scott Carney: People jump ship to Instagram for solutions when Western medicine doesn’t have the tools to treat chronic conditions like IBS or brain fog. What are the dangers of this approach?
Matt Kaeberlein: The problem is that most of these experimental therapies haven’t been tested for safety or efficacy. Regulatory approval gives you confidence that it works and is safe. Outside of that, you face two major risks. First, is the therapy itself safe? With stem cells, the consequences can be catastrophic—paralysis, cancer, or death. Second is the manufacturing piece. There is a black market now. You might get impurities or the vial might not contain what the label claims. Impurities cause the severe allergic reactions and infections that make people very sick.
Offshore clinics for medical tourism often aren’t run by the highest quality professionals. You run the risk of getting care from someone sloppy or uninformed.
Scott Carney: My investigation into the black market has shown that while Dezawa Muse cells are hot and come from a lab in Japan, other clinics have an incentive to cut corners. A package from the real lab might cost a clinic $5,000, but they can find “counterfeit” cells with similar markers for $500, increasing their profit by $4,500. I’m hearing stories of people smuggling frozen cells across borders, driven by the marketing of health influencers.
Matt Kaeberlein: That is exactly accurate. I know stories of cells being smuggled across borders. Once you get outside the official regulatory environment, all bets are off. There are dishonest people who just change the label. Stem cells are particularly problematic because you can’t just do a $50 test like you can with a pill like Metformin to check purity. You need specialized equipment to verify if they are actually Muse cells. Personally, I would never do them right now because I have no idea who to trust.
Scott Carney: This brings us to Mark Hyman, the father of functional medicine and a conduit to RFK Jr. In my first video, I discussed how he got a stem cell shot from Adeel Khan’s Eterna Health clinic in Mexico and got so sick he almost died. What are your observations on that case?
Matt Kaeberlein: I don’t know the specifics firsthand, but anybody networked in the longevity field knows that what happened to Mark Hyman is not a one-off. It has happened before and will happen again. My understanding, based on three or four different sources, is that Mark went to a clinic in Mexico and had a catastrophic reaction. The story is that it was sepsis caused by bacterial contamination, likely from the water used in the procedure or a lack of sterile conditions.
Two sources told me they got the information from a WhatsApp group where Mark shared this with other longevity doctors. Now, every person has the right to keep their medical history private, but if it were me, and I was someone who recommended these therapies to others, I would feel an ethical and moral obligation to share that warning. Mark has not done that.
Scott Carney: He has a massive platform recommending various treatments. It’s also possible the contamination came from the preparation of those Muse cells, which might have come from an off-brand lab to save money. There’s also the issue of “stacking” treatments. Jordan Peterson, for example, didn’t just get stem cells; he was talking to Tony Robbins, getting fecal transplants, and trying multiple experimental things at once. Is that additionally risky?
Matt Kaeberlein: Of course. Combining interventions comes with additional risks because we don’t understand how these complex biological interactions work in the human body. However, I have empathy for the patients. Desperation for a debilitating condition is natural.
I think we should be looking for solutions. Are there ways to allow people access safely while we wait for long clinical trials? We are starting to see “Right to Try” laws in states like Montana, New Hampshire, and Florida. These allow licensed practitioners to provide experimental therapies with full informed consent and oversight from a review board. If safeguards are put in place for manufacturing and quality control, it could be a useful middle ground. We should villainize bad actors, but also help people who are suffering.
Scott Carney: That sounds amazing if it happens. RFK Jr. has even appointed Tony Robbins as a medical advisor. But let’s talk about peptides, because that connects immediately. It seems everyone is doing peptides now—GLP-1s, insulin, etc. I asked Dave Asprey years ago what the next big thing was, and he said peptides. He was right. Tell me about them.
Matt Kaeberlein: The way the word “peptide” is used on Instagram is not what the word actually means. Peptides are just a class of biomolecules ubiquitous in nature. They are like any other drug—some are safe, some are toxic (like cobra toxin). They aren’t a magic class of drug that is all good and no bad.
We should bucket them:
FDA-Approved Peptides: Like GLP-1 agonists (Ozempic/Tirzepatide) for obesity, or growth hormone boosters. Doctors can prescribe these “off-label” for body composition.
Unapproved Peptides: Like BPC-157, GHK-copper, or TB500. These have never gone through human clinical trials.
There is widespread illegal prescribing and manufacturing of these unapproved peptides that the FDA is largely ignoring—like traffic laws where everyone is speeding. Several years ago, the FDA put about 19 peptides on a “no compound” list because people were being hospitalized. RFK Jr. has talked about “stopping the war on peptides,” which likely means moving those back to the legal compounding list. Even then, it’s still technically illegal for a doctor to prescribe them because they aren’t FDA approved.
Scott Carney: It’s a big experiment. In the 1930s, there was a weight loss pill called DNP that ramped up metabolism and people literally burned up from the inside.
Matt Kaeberlein: DNP (dinitrophenol) is a “mitochondrial activator” and a potent uncoupling agent. It makes the cell burn energy like an engine idling at a high rate. The problem is that burning energy generates heat. In the 1930s, reports popped up of people with hyperthermia so severe they died. You can’t just shut it off once it starts.
I don’t think modern peptides are in the same class as DNP, but it’s a lesson in what happens when you mess with fundamental biology. Some peptides are marketed as mitochondrial activators. We need randomized trials so people don’t die unnecessarily. It’s a fallacy of human nature to assume that if there’s no data, it must be safe. We have decades of data on Statins, so people focus on the known side effects and call them “terrible.” But with a brand new peptide with zero data, people assume it’s magic.
Scott Carney: You mentioned a trip to “Radfest” in Las Vegas recently. What happened there?
Matt Kaeberlein: Radfest started as a fringe conference for people who want to live forever. Recently, they’ve added a science track with legitimate researchers, which is why I was invited. But the vendor hall was wild. There was a doctor giving out peptide injections in the hall with no medical history or screening. On the last day, two women were hospitalized with severe reactions and almost died.
In another instance, a colleague invited me to a hotel room to get exosomes. I went along but didn’t take them. A woman—not a doctor, but a wellness clinic owner—had a freezer bag full of tubes. She said she could tell what dose they needed by “feeling their energy.” She started waving her hands around and even asked if she could “send me some of their energy.” My colleagues actually went through with the injection. These are smart people! It just shows the bizarre risk-reward calculations people are making.
Scott Carney: What exactly is an exosome?
Matt Kaeberlein: They are vesicles given off by cells, usually stem cells. They are like growth signals. The theory is that instead of injecting whole stem cells, you inject these concentrated signals. But cells also use exosomes as a garbage dump to get rid of junk they don’t want. So when you take them, you’re getting a mix of “good stuff” and cellular garbage.
Scott Carney: That’s a perfect metaphor for the field. So, should anyone actually look for regenerative treatments?
Matt Kaeberlein: It comes down to individual choice. I’m fairly libertarian about healthcare; if someone is fully informed of the risks, they should have access. If you’re in a position where you’re seeking a “Hail Mary,” spend your time researching how to protect yourself. Use AI tools to find both sides of the story. If you go to an offshore clinic and it’s dirty or the doctor seems uninformed, get out. In my experience, clinics in Singapore and certain parts of Europe tend to be higher quality than those in Latin America.
Scott Carney: I have a different opinion. Most people find “trust” through Instagram and influencers like Mark Hyman. They don’t have your access to the actual scientists. By the time they fly to Mexico, they’ve sunk so much cost that they’ll believe whatever the doctor says.
Matt Kaeberlein: I don’t disagree. I can’t fix why people believe liars on Instagram.
Scott Carney: Recently, David Sinclair went on The Diary of a CEO and said there will soon be a pill that can reverse your age, and that he’s cured blindness in dogs. Is he on the up and up?
Matt Kaeberlein: No. David has a track record of saying things that aren’t true. Usually, scientists face consequences for that, but he seems to avoid them. Nobody has made an old mouse or person young again. Period.
It is easy to reverse certain aspects of aging—if I dye my gray hair black, I’ve “reversed” a feature of aging, but I’m not younger. Some researchers have used “epigenetic reprogramming” to make cells function better. In a specific mouse eye disease model, this partially reversed blindness. Sinclair’s company, Life Biosciences, has FDA approval to start human trials for specific eye conditions. That’s real progress, but we are 5 to 10 years away from clinical medicine. The idea that it will cure all blindness or make 60-year-olds into 20-year-olds is just nonsense.
Scott Carney: Starting a trial is not the same as finishing one. Marketing it as an “announcement” on a podcast is problematic. One last thing: You mentioned stem cells are less effective in older people. I know we disagree on the concept of “biological age,” but if someone “reverses” their biological age through cellular means, would stem cells work better?
Matt Kaeberlein: It depends. Biological age is an “emergent property”—thousands of mechanisms lead to it. You can reverse some without reversing everything. But yes, if you bring down chronic inflammation (inflammaging), you allow the remaining stem cells to do their jobs better.
Speculatively—and this is not medical advice—animal data suggests a short fast or a course of Rapamycin before stem cell therapy might improve results by blunting inflammation. But I haven’t done the experiment in humans, so I’m just speculating.
Scott Carney: I love that you retracted the fasting comment so quickly! We live in a world where everything is a touchstone issue.
Matt Kaeberlein: I did it because I’m a scientist and I don’t have the human data yet. Also, I personally like to eat, so I’m anti-fasting for personal reasons!
Scott Carney: I’m with you there! Matt, thanks again for being on the show. Next week, we’re diving deeper into the black market, Adeel Khan, and some very sketchy “receipts” I’ve received from confidential sources. Stay tuned.
Matt Kaeberlein: I’m looking forward to it. I’m a premium subscriber now, so I’ll be watching!
Scott Carney: From Denver, Colorado, this was Scott Carney Investigates.
