Unproven stem cell clinics: why they spread and the warning signs

Stem cell biology is one of the real success stories of modern medicine. Blood stem cell transplants have treated leukemia and inherited blood disorders for decades, cord blood units are licensed by the FDA, and new cell therapies keep reaching approval. That record is exactly what makes the field easy to borrow from. Alongside it, a large commercial market has grown up selling "stem cell" injections for conditions where no such treatment has been shown to work.

This piece covers how that market grew, what it sells, what has gone wrong, what regulators have done, and how a patient or family member can tell the difference between a clinical trial and a sales pitch.

How big the market became

In 2016, bioethicist Leigh Turner and stem cell biologist Paul Knoepfler published a survey in the journal Cell Stem Cell that found 351 US businesses marketing stem cell interventions directly to consumers, through 570 clinics. When Turner repeated the exercise, a 2021 paper counted about 1,480 businesses operating more than 2,700 clinics. The growth happened while the FDA was warning, in public and repeatedly, that most of these products had never been approved.

Why these clinics spread

Several forces pushed in the same direction.

• Real hope. Patients with arthritis, multiple sclerosis, ALS, Parkinson's disease or autism in the family often have limited options, and headlines about genuine research make a cell injection sound like the next logical step.
• A regulatory argument. US rules let some minimally processed human cells and tissues be used without FDA approval, under narrow conditions, and allow a "same surgical procedure" exception when tissue is removed and put back during one operation. Many clinics argued their products fit these exceptions. Courts have since rejected that argument for common clinic procedures.
• A grace period. In late 2017 the FDA announced a policy framework that gave businesses time to come into compliance, with limited enforcement against lower-risk products. The grace period was extended once and ended on May 31, 2021.
• Cash and marketing. Treatments are typically paid out of pocket, often thousands of dollars per round, and sold through seminars, social media and patient testimonials.
• Borrowed credibility. Some businesses register patient-funded "studies" on ClinicalTrials.gov. A listing there is not an approval or an endorsement, which our guide to reading a ClinicalTrials.gov listing explains in detail.

What they sell

Offerings vary, but most fall into a few groups:

1. Fat-derived cells, often called stromal vascular fraction (SVF), taken by liposuction, processed on site and injected back into joints, veins or the spinal fluid.
2. Bone marrow aspirate concentrate, drawn from the hip and injected elsewhere.
3. Products described as coming from umbilical cord, cord blood, amniotic fluid or placenta, usually bought from a supplier and marketed as rich in living "stem cells."
4. Exosomes and other cell-derived "secretome" products, which contain no cells at all.
5. Intravenous infusions sold for whole-body conditions, from lung disease to "anti-aging."

Many of these pitches lean on mesenchymal stromal cells, a real cell type with a real research record. Our explainer on bone marrow and mesenchymal stromal cells covers what those cells are and what controlled trials have and have not shown.

What has gone wrong

Nobody knows how often things go wrong, because clinics selling unapproved products are not required to track outcomes. The cases that have been documented are severe, and they appear in some of medicine's most closely read journals.

• 2016, New England Journal of Medicine. Doctors in Boston described a man who developed an abnormal growth in his spinal cord after receiving stem cell infusions at clinics in China, Argentina and Mexico. They reported it as a complication of the treatments.
• 2017, New England Journal of Medicine. Eye specialists reported three women with macular degeneration who had fat-derived cell preparations injected into both eyes on the same day at a Florida clinic. All three suffered severe vision loss, and one was left with no light perception.
• 2018, CDC. A report in the agency's Morbidity and Mortality Weekly Report described 12 patients in Texas, Florida and Arizona who developed bloodstream or joint infections after receiving bacterially contaminated, unapproved products derived from umbilical cord blood. All were hospitalized. The CDC report is public.
• 2019, FDA. The agency issued a safety notification on exosome products after serious adverse events in patients in Nebraska, and stated that there are no FDA-approved exosome products.

There are quieter harms too: money spent that families could not spare, and time lost on treatments that delayed care with proven benefit.

What the FDA and the courts have done

• 2017. US Marshals, acting for the FDA, seized vials of a smallpox vaccine reserved for high-risk groups that had been used to make an unapproved cancer product given at a California clinic network. The FDA also sent a warning letter to a Florida clinic.
• 2018. The Justice Department, on the FDA's behalf, filed complaints seeking permanent injunctions against US Stem Cell Clinic in Florida and the California Stem Cell Treatment Center.
• 2019. A federal court in Florida ruled for the FDA and barred the Florida clinic from offering its fat-derived cell product until it could show the agency it was safe and effective.
• 2021. The grace period ended on May 31, and in June the Eleventh Circuit Court of Appeals upheld the Florida ruling.
• 2022. A federal district court in California sided with the California clinic, finding its procedure fell under the surgical exception.
• 2024. In September, the Ninth Circuit reversed that decision, holding that the clinic's SVF product is a drug that needs FDA approval.

The FDA has also sent warning letters and other notices to many businesses selling cord, amniotic and exosome products, and the Federal Trade Commission has acted against deceptive stem cell advertising. The FDA's page of information for patients about regenerative medicine therapies states that the only stem cell products it has approved are blood-forming stem cells from cord blood, for disorders of the blood and immune system.

Two resources from the ISSCR

The International Society for Stem Cell Research, the main professional body in the field, publishes two resources written for patients.

The first began as the ISSCR Patient Handbook on Stem Cell Therapies and lives on, revised and expanded, as the ISSCR Guide to Stem Cell Treatments. It explains how a laboratory finding becomes a tested treatment, what a clinical trial should include, and why "it's your own cells" does not make a procedure safe.

The second is the society's public website, launched as A Closer Look at Stem Cells and now found at AboutStemCells.org. Its short list of nine things to know about stem cell treatments is a good page to send a relative who has just been handed a clinic brochure.

Warning signs

Any one of these deserves a closer look. Several together are a strong signal.

• One treatment offered for many unrelated diseases.
• Claims of little or no risk, or "no side effects because the cells are your own."
• Patient testimonials in place of published, peer-reviewed results.
• Payment up front for something described as experimental.
• A ClinicalTrials.gov number or "FDA registered" status offered as proof of approval.
• Vague answers about where the cells come from, how many there are and how they were processed.
• Deadlines, discounts or "limited spots" that push for a quick decision.
• Travel and treatment packages bundled together.
• Little interest in your medical records, and no plan for follow-up or complications.

Questions to ask

1. Is this treatment approved by the FDA for my condition? If not, is it being given under an investigational new drug application, and what is the number?
2. Has an independent institutional review board approved the study? Can I see the protocol and the consent form before deciding?
3. What published evidence supports it, from which trials, and were those trials controlled?
4. Where do the cells or products come from, how are they processed, and how is each batch tested for sterility and identity?
5. What are the known risks, who handles complications, and who pays for that care?
6. Why am I being charged? In most legitimate trials participants do not pay for the experimental product, and the FDA allows charging only in limited, authorized circumstances.
7. How will results be measured, and will they be shared with my own doctor?

Clinicians who field these conversations can find a longer discussion on our page about talking with patients about stem cell clinics.

Where legitimate trials are listed

• ClinicalTrials.gov, run by the US National Library of Medicine, is the largest public registry. Listing is required for many trials but is not a sign of quality.
• The World Health Organization's International Clinical Trials Registry Platform searches national registries around the world in one place.
• Large academic medical centers and disease-specific patient organizations often maintain lists of open studies and can help interpret them.

Anyone harmed by a stem cell or exosome product can report it to the FDA through MedWatch.

One fast check before any appointment: search ClinicalTrials.gov for the clinic's name. If the only study that comes up charges participants, enrolls people with a long list of unrelated conditions and names the clinic's owner as both sponsor and investigator, that single listing tells you most of what you need to know.