Is stem cell therapy legal in the U.S.? Where the FDA draws the line
Whether stem cell therapy is legal in the U.S. depends on which side of an FDA line the product falls. There is a four-part test the FDA uses to decide whether a cell preparation is a tissue your clinic can use or a drug that needs a multi-year approval.
Pass all four prongs, you're a tissue. Miss one, you're a drug. Every U.S. stem-cell clinic, every piece of marketing language, every regulatory disclosure on every clinic's website is shaped by which prong they're trying not to fail.
A cell preparation
- Minimally manipulated?No
- Homologous use?No
- Not combined with a drug or device?No
- Autologous, or no systemic effect?No
Pass all four prongs Section 361 tissue. No IND, no trial, no FDA drug review.
Miss any prong Section 351 biologic drug. Requires an active IND, a trial sponsor, and FDA review: a path that takes years.
How does the FDA decide what is a tissue and what is a drug?
The FDA's framework, codified at 21 CFR 1271.10, is structured as a gate. Every cell preparation a U.S. clinic offers either passes through it or doesn't. There's no middle tier, no "lightly regulated as a drug" category. You're either a tissue (Section 361) or a biologic drug (Section 351). The gate decides which.
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Each prong is a binary; the answers don't average.
Every clinic in the United States offering "stem cell therapy" is, whether they say so or not, operating their entire program around staying on the left side of this gate. The cells they offer, the volumes they draw, the same-day workflow, the language on their website, the indications they will treat, all of it is shaped by the four prongs above.
2,754 U.S. clinics shaped by it. Every same-day workflow, autologous-only protocol, and "homologous-use" marketing line traces back to one of these prongs.
Minimally manipulated.
The processing doesn't change the cell's "original relevant characteristics." Centrifugation, washing, freezing, yes. Cell culture, expansion, differentiation, no.
Used for the same job.
"Homologous use." Bone graft → repair bone, yes. Fat cells → repair a knee, no. The cells must be doing the same basic biological function they did in their original location.
Not combined with a drug or device.
With narrow exceptions (sterilizing/preserving agents). Mixing in a pharmaceutical, a growth factor, or a structural scaffold typically pushes the product across the line.
No systemic effect, or, if there is, it's your own cells.
If the product depends on the metabolic activity of living cells, or acts systemically, it has to be autologous (your own) or from a first/second-degree blood relative. Otherwise it's a drug.
Miss one prong and it's a drug.
A drug requires an Investigational New Drug application (IND), trial sponsors, and FDA review. Without one, you are operating in violation. See the landscape
What does "minimally manipulated" mean?
21 CFR 1271.10(a)(1) · 1271.3(f)
The first prong asks whether the processing alters the tissue's "original relevant characteristics". Translating: the cells you put in have to be doing the same thing, structurally and biologically, as the cells that came out. Wash them. Spin them. Filter them. Freeze them. Fine. The moment you culture them, give them food and time to multiply, you have manipulated them more than minimally, and the gate closes.
Translation: you didn't change what the cells are. You moved them, you cleaned them, you maybe concentrated them. You did not feed them, expand them, differentiate them, or otherwise re-engineer them.
- Washsaline
- Spincentrifuge
- Filtersieve
- Cryopreservefreeze · thaw
Minimal manipulation · Section 361 tissue
The regulatory line
- Enzymatic SVFruled a drug
- Culturefeed · expand
- Differentiateinduce identity
- Gene-modifyedit DNA
More-than-minimal · Section 351 drug
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Counts as minimal
- Centrifuging to concentrate
- Washing with saline
- Filtering or sieving
- Cutting, shaping, sizing
- Cryopreserving and thawing
Counts as more-than-minimal
- Cell culture (giving cells food to multiply)
- Expanding from millions to billions
- Inducing differentiation
- Genetically modifying
- Breaking down fat to isolate SVF, by enzymes or by mechanical disruption*
- Combining with growth factors to drive proliferation
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* Stromal vascular fraction is where clinics have fought this prong hardest. FDA's guidance says that breaking down fat to isolate SVF, by enzymatic digestion or by mechanical disruption, is more-than-minimal manipulation. Many U.S. clinics disputed this. US Stem Cell (S.D. Fla., 2019, summary judgment; affirmed by the Eleventh Circuit in 2021) sided with FDA. California Stem Cell Treatment Center won at the district court in 2022, but the Ninth Circuit reversed in September 2024 and the Supreme Court declined to take the appeal in October 2025. Both federal appeals courts that have ruled on SVF have sided with FDA.
This is the prong that forces the most visible practice in U.S. stem-cell medicine: same-day, in-clinic procedures. If the cells leave the body, get cultured for two weeks, and come back as a billion-cell infusion, they're a drug. So the cells never leave. They go from your hip to a benchtop centrifuge to a syringe to your knee, all in 90 minutes. That entire workflow exists because of one phrase in one subsection of the Code of Federal Regulations.
What is homologous use?
21 CFR 1271.10(a)(2) · 1271.3(c)
The second prong asks a question that feels intuitive once you see it: are the cells doing the same job in the new location as they did in the old one? Bone marrow used to repair bone: homologous. Skin used to repair skin: homologous. Fat-derived cells injected into a knee to "regenerate cartilage": not homologous, because fat tissue's job in the body is not cartilage maintenance.
Translation: the cells must do the same biological job in the new place as they did in the old place. Repair, reconstruction, replacement, or supplementation, of the function the source tissue was already performing.
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Bone graft to bone repair
Homologous · Section 361 OK
A piece of bone, debrided and placed into a non-union fracture, is doing the same thing it was doing before. Same job, new location. Passes.
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Adipose SVF to knee cartilage
Non-homologous · Section 351 drug
Fat tissue's job is energy storage and cushioning. Injecting fat-derived cells to regrow articular cartilage is asking them to do a job they did not do in the donor site. Fails this prong.
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Cornea to cornea transplant
Homologous · Section 361 OK
A cornea used for corneal replacement is the textbook case. Same tissue, same role, different person.
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Bone marrow to systemic IV "for everything"
Non-homologous · Section 351 drug
Bone marrow's role is hematopoiesis. Marketing it as a systemic anti-inflammatory infusion for autoimmune disease, brain fog, or "longevity" turns it into an unapproved drug for a new indication.
FDA evaluates homologous use against the manufacturer's objective intent: the labeling, the advertising, the indications the clinic claims to treat. Saying nothing on the website does not exempt the use; the diagnosis on the consent form and the protocol document also count as intent.
This is the prong most U.S. wellness clinics quietly fail in their marketing. The treatment itself might be a Section 361-defensible same-day preparation. But the page that says "stem cells for autoimmune disease, neurodegenerative conditions, and anti-aging" describes a use that is, by FDA's reading, non-homologous, and therefore a drug.
The cells didn't change. The intent did. That's enough to move a product across the line, from a procedure your doctor performs to an unapproved drug your doctor is dispensing.
What does "not combined with another article" mean?
The third prong is narrower than the first two, but it has real teeth. If a clinic mixes the cells with a pharmaceutical compound, say, a growth factor, a steroid, a synthetic scaffold material, an exosome cocktail from a different source, the resulting product is generally no longer a Section 361 tissue. It has become a combination product, evaluated as a drug.
Translation: cells stand alone. They can travel in a buffer. They can be preserved. They cannot be co-administered with a separate active pharmaceutical compound or a synthetic structural device.
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Permitted combinations
- Saline carrier
- DMSO and similar cryoprotectants
- Sterilizing agents that don't remain at point of injection
- Preservatives below threshold
- Water, anticoagulants, sodium citrate
Pushes you to Section 351
- Added growth factors (PDGF, BMP, VEGF)
- Added steroids or anti-inflammatories
- Added exosomes from an unrelated source
- Mixed allogeneic and autologous in the same product
- Scaffolds, gels, hydrogels with active function
- Co-formulated with a regulated device
The third prong is where a lot of "advanced" or "premium" U.S. offerings quietly cross into drug territory. A clinic offering "stem cells with exosomes and growth factor matrix" is, regardless of marketing language, describing a combination product. The product as a whole is what FDA evaluates, not just the cell fraction.
Why are donor stem cells given by IV a drug in the U.S.?
21 CFR 1271.10(a)(4)(i) and (ii)
The fourth prong is the most technical, and most clinics talk around it. It splits into two halves. (i) If the cell preparation does not depend on the metabolic activity of living cells for its primary function, and does not act systemically, it's fine, no further test. (ii) If it does depend on living cells, or does act systemically, then it has to be either autologous (the patient's own cells) or from a first/second-degree blood relative, or for reproductive use.
Translation: if the cells are alive and doing things, they have to come from you (or a close blood relative). Otherwise the patient's own immune system isn't the only safety guard, and FDA wants drug-level evidence.
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Passes prong 4
- Patient's own cells, drawn and returned
- Bone marrow from a sibling, used in a related role
- Reproductive cells (sperm, eggs)
- Decellularized tissue scaffold, no living cells
- Acellular dermal matrix
Fails prong 4 → Section 351
- Allogeneic umbilical cord cells, IV systemic, unrelated donor
- Pooled donor MSCs for systemic infusion
- Wharton's jelly cells given IV to unrelated patient
- Cultured donor cells, any systemic route
The fourth prong is what makes "allogeneic IV stem cells" the offering most patients researching this space are actually looking for, categorically a Section 351 drug in the United States, requiring an active IND. There is no Section 361 path to systemic donor cells.
How to read U.S. stem cell clinic marketing
The line is precise. Clinics try to walk it. Most walk it through their marketing copy, not their lab work.
Most prospective patients never read the CFR. They read clinic websites. Once you know the four prongs, every familiar phrase in U.S. stem-cell marketing maps to one of them, usually as a careful sidestep around a prong the clinic does not want to fail.
What clinics say, what the FDA hears.
"Same-day procedure, your own cells."
Which prong it protects Prongs 1 + 4. No culture (minimal manipulation) and autologous (clears the systemic prong).
In plain English We do everything between your hip and your knee in one visit. The cells never leave the room.
"Minimally manipulated."
Which prong it protects Prong 1. A literal recitation of CFR language to claim Section 361 status.
In plain English We washed and spun your cells. We did not culture or expand them.
"Supports the body's natural healing."
Which prong it protects Prong 2. Vague language to avoid claiming a specific non-homologous indication.
In plain English If we name a disease, we're claiming a use. If we claim a use that isn't what the source tissue did, we're a drug. So we stay vague.
"Stromal vascular fraction (SVF)."
Which prong it protects Prong 1 (claimed). Clinics argue that preparing SVF is "minimal manipulation." FDA says it is not, and two federal appeals courts have agreed.
In plain English Cells freed from fat, usually by enzymes. FDA says it's a drug. The clinic argues it isn't. The courts have agreed with FDA.
"Umbilical-derived stem cells, IV."
Which prong it protects Fails prong 4 unless administered under an active IND. Allogeneic, systemic, unrelated donor.
In plain English This is an unapproved drug under U.S. law unless the clinic has an FDA-cleared trial. Most don't.
"Expanded MSCs · cultured for potency."
Which prong it protects Fails prong 1, period. Culture is more-than-minimal.
In plain English By definition, a drug under U.S. law. Requires an IND to administer.
"Stem cells with exosomes and growth factors."
Which prong it protects Fails prong 3. Combined with a separate active article.
In plain English Even if the cells alone pass, the combination is a drug.
"For research purposes only."
Which prong it protects An attempt at prong-bypass. Used by clinics to disclaim therapeutic intent.
In plain English FDA evaluates objective intent, not disclaimers. If the consent form bills for a treatment, the disclaimer is decorative.
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The FDA's four-prong test isn't a vibe or a guideline. It's a structured logical filter. A given preparation passes it or doesn't. Cell culture status, donor source, indication claim, mix composition: each one is a binary. The patient-facing complication is that most U.S. clinic websites are written by marketing teams and read by people who have never seen 21 CFR 1271, so the language is calibrated to sound medical and FDA-compliant without committing to any specific prong.
The fastest way to read a U.S. stem-cell clinic page, once you know the four prongs, is to ask which prong it's protecting and what the answer would be if you cross-examined them under oath. The honest clinics, and a few exist, will tell you exactly which prong they sit under and why. The rest will use words like "supports" and "advanced" and "personalized" until you stop asking.
Who regulates stem cell advertising: the FDA or the FTC?
The FDA decides whether the product is legal to sell. The Federal Trade Commission decides whether the advertising that sells it is honest. These are two different statutes, two different agencies, and two different standards of proof. A U.S. clinic can satisfy one and be crosswise with the other.
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FDA jurisdiction: the product.
Statute is the Federal Food, Drug, and Cosmetic Act. Tools are warning letters, seizures, injunctions, criminal referral. Remedy targets the manufacture and the path to market. The four prongs above are the test.
FTC jurisdiction: the advertising.
Statute is Section 5 of the FTC Act, with Section 12 covering false advertising of drugs, devices, and services specifically. The threshold for every health claim is "competent and reliable scientific evidence" for the specific indication and the specific product. Tools are consent orders, civil penalties, monetary refunds, and permanent bans on the people who signed off on the ads.
One of the largest stem-cell advertising judgments in the U.S. came through the FTC, not the FDA.
In December 2024, a federal court in Georgia entered a judgment of more than $5.1 million against the founders of Stem Cell Institute of America and Superior Healthcare, and permanently banned them from advertising, marketing, promoting, or selling any regenerative-medicine treatment that meets the definition of stem-cell therapy. The product was not novel. The marketing was.
If you're reading U.S. clinic websites, the practical upshot is simple. An FDA warning letter is about what is in the syringe. An FTC consent order is about what is on the page. A clinic can revise the preparation to satisfy the FDA and keep getting sued by the FTC because the marketing keeps over-promising. The phrase "FDA-regulated" on a clinic page, written to imply that the agency has cleared something it has not, is the kind of sentence that triggers both.