On Tuesday, federal regulators with the Food and Drug Administration warned people against getting transfusions of young blood for their alleged anti-aging and other health benefits.
"There is no proven clinical benefit of infusion of plasma from young donors to cure, mitigate, treat, or prevent these conditions, and there are risks associated with the use of any plasma product," wrote FDA commissioner Scott Gottlieb and the director of FDA's center for biologics evaluation, Peter Marks, in a joint statement .
The statement didn't call out any companies by name.
One of the only known companies currently offering the procedure is called Ambrosia. The company charges $8,000 for 1 liter of young blood or $12,000 for 2 liters.
As Business Insider previously reported, Ambrosia's founder, Jesse Karmazin, has said the transfusions are safe and reliable, despite little to no hard scientific evidence to demonstrate either its safety or any potential benefits. Karmazin didn't immediately return a message seeking comment on the FDA statement.
Roughly three years ago, Karmazin launched Ambrosia, claiming that the procedure would help conquer aging by rejuvenating the body's organs.
The company is now up and running, Karmazin told Business Insider last month. Ambrosia recently revamped its website with a list of clinic locations and is now accepting payments for the procedure via PayPal.
In the fall, Karmazin who is not a licensed medical practitioner and who graduated from Stanford Medical School told Business Insider he planned to open the first Ambrosia clinic in New York City by the end of the year. That didn't happen. Instead, he said, the sites where customers can get the procedure include Los Angeles; San Francisco; Tampa, Florida; Omaha, Nebraska; and Houston, Texas.
In 2017, Ambrosia enrolled people in a clinical trial designed to find out what happens when the veins of adults are filled with blood from younger people. While the results of that study have not been made public, Karmazin told Business Insider in September that they were "really positive."
But because the Food and Drug Administration has approved blood transfusions, Ambrosia's approach has been able to continue as an off-label treatment .
There appears to be significant interest. A week after putting up its first website in September, the company received roughly 100 inquiries about how to get the treatment, David Cavalier , Ambrosia's chief operating officer at the time, told Business Insider in the fall. That led to the creation of a waiting list, Cavalier said.
In January, Cavalier told Business Insider he'd left Ambrosia, leaving Karmazin as the company's only public employee.
Before departing from Ambrosia, Cavalier worked with Karmazin to scout several potential clinic locations in New York and organize talks with potential investors, he said.
Ambrosias first clinical trial
Because blood transfusions are already approved by federal regulators, Ambrosia does not need to demonstrate that its treatment carries significant benefits before offering it to customers.
As of September, the company had infused close to 150 people, ranging in age from 35 to 92, with the blood of younger donors, Cavalier said. Of those, 81 participated in its clinical trial .
The trial, which involved giving patients 1.5 liters of plasma from a donor between the ages of 16 and 25 over two days, was conducted with David Wright, a physician who owns a private intravenous-therapy center in Monterey, California . Before and after the infusions, participants' blood was tested for a handful of biomarkers, or measurable biological substances and processes thought to provide a snapshot of health and disease.
Trial participants paid $8,000, the same price as one of the procedures now listed on Ambrosia's website.
"The trial was an investigational study," Cavalier said in September. "We saw some interesting things, and we do plan to publish that data. And we want to begin to open clinics where the treatment will be made available."
Karmazin added in September that he believed the trial showed the treatment to be safe.
Young blood and anti-aging: Are there any benefits?
Karmazin is right about blood transfusions' capacity to save lives.
A simple blood transfusion, which involves hooking up an IV and pumping the plasma of a healthy person into the veins of someone who's undergone surgery or been in a car crash, for example, is one of the safest life-saving procedures available. Every year in the US, clinicians perform about 14.6 million of them , meaning about 40,000 blood transfusions happen on any given day.
But the science remains unclear about whether infusions of young blood could help fight aging.
In early experiments in mice, Tony Wyss-Coray , a director of the Alzheimer's research center at Stanford University Medical School who founded a longevity startup focused on blood plasma called Alkahest , found that swapping old blood plasma for young blood plasma appeared to provide some limited cognitive benefits . The 150-year-old surgical technique he used, parabiosis whose name comes from the Greek words "para," or "beside," and "bio," or "life" involves exchanging the blood of two living organisms.
After Wyss-Coray's mouse experiments, he and a team of Alkahest researchers took a big leap and in 2017 completed a monthlong study in which they transfused a standard unit of blood plasma from younger, healthy human volunteers into nine older adults with mild to moderate Alzheimer's disease.
Their results were published in January in the journal JAMA Neurology. Because the study was small and short, the authors were fairly limited in drawing conclusions about what kind of benefits the plasma offered. They described the treatment as "safe, well tolerated, and feasible" and said the findings should be explored further in larger trials.
But Alkahest's work is very different from Ambrosia's.
As Business Insider previously reported, Alkahest researchers want to develop drugs for age-related diseases that are inspired by their work with plasma; they are not looking to open a clinic.
The results looked really awesome
Nevertheless, Karmazin is optimistic that blood has a range of benefits. He got the idea for his company as a medical student at Stanford and an intern at the National Institute on Aging, where he watched dozens of traditional blood transfusions performed safely.
"Some patients got young blood, and others got older blood, and I was able to do some statistics on it, and the results looked really awesome," Karmazin told Business Insider in 2017. "And I thought this is the kind of therapy that I'd want to be available to me."
So far, no one knows whether young blood transfusions can be reliably linked to lasting benefits.
Karmazin said that "many" of the roughly 150 people who had received the treatment described benefits including renewed focus, better memory and sleep, and improved appearance and muscle tone.
However, it's tough to quantify these benefits before the study's findings are made public. There's also the possibility that simply traveling to a lab in Monterey and paying to enroll in the study could have made the people feel better.
But Karmazin remains hopeful that the benefits he said he's seeing are the result of young-blood transfusions.
"I'm really happy with the results we're seeing," he said in September.
"We strongly discourage consumers from pursing this therapy outside of clinical trials under appropriate institutional review board and regulatory oversight," Gottlieb and Marks wrote in their letter this Tuesday.
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