A Plain-English Glossary of Regenerative Medicine Terms

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Sources on this page: www.fda.gov · www.ecfr.gov

A Plain-English Glossary of Regenerative Medicine Terms

Most of these words name a material, not a treatment. Knowing which material is being discussed tells you which regulatory frameworks to check first. It does not always settle the result on its own: how the material was processed, what it is intended to do and what it has been combined with can move a preparation from one framework into another.

Each entry below is built around three questions: what the thing physically is, where it comes from, and where to look for its regulatory position. Entries are not all the same length, and the reason is always the same one. Where a primary source says something short and exact, it is quoted here. Where no source names the term, that is stated too, and saying so takes more words than quoting. No term is described as promising, effective or safe.

What this page deliberately does not do. It does not state whether a product is approved, and it does not quote licensed indications. A term is not a product, and the position belongs to the specific product rather than to the word. This page gets you to the right word; two others carry the records.

Where the entries below send you, said once. Anything about approval status or a licensed indication goes to our approvals page. Anything about whether a preparation meets the four criteria, or falls under the same-surgical-procedure exception, goes to our page on those criteria. Below, an entry that says the four criteria or the licensed list means those two pages; it is not repeated every time.

How to use this glossary

Find the word you were given and read its entry. Then take the term back to the person who used it and ask whether that is what they meant, because several of these words are used loosely in conversation and precisely in documents.

A regulatory position note points you to the check. It is not the finding.

Where the material comes from

Autologous. Material taken from a person and returned to that same person. The FDA guidance on the same surgical procedure exception discusses this category directly, and being autologous appears in the rules as one condition among several rather than as a general exemption.

Allogeneic. Material from one person used in a different person. The regulatory criteria treat some allogeneic uses differently depending on the relationship between donor and recipient, including use in a first or second degree blood relative.

HCT/P. Human cells, tissues, and cellular and tissue based products. Several of the terms below name materials that fall into this category. The four criteria in 21 CFR 1271.10(a) apply to products that do.

And the same regulation names what is not one. Two of its exclusions matter on this page. Whole blood, blood components and blood derivative products subject to listing are not HCT/Ps. Neither are secreted or extracted human products, the regulation’s examples being milk, collagen and cell factors, with semen named as the exception.

Source: 21 CFR 1271.3(d)(2) and (d)(3). Accessed 18 September 2026.

This matters more than it looks. A material that falls under an exclusion does not travel the four-criteria route at all, so the first question about any preparation is not how it was processed. It is whether it is an HCT/P to begin with. Two entries below are there precisely because the answer is no.

Cell-based terms

Stromal vascular fraction, abbreviated SVF. A mixed population of cells separated from fat tissue. The FDA guidance describes a process in which adipose tissue is recovered and then processed “to isolate cellular components (with or without subsequent cell culture or expansion), commonly referred to as stromal vascular fraction.” Where to look: the four criteria, because how the cells were separated is central to that assessment. This term is also named in the FDA enumeration quoted under A2M below.

Source: FDA, “Regulatory Considerations for Human Cells, Tissues, and Cellular and Tissue-Based Products: Minimal Manipulation and Homologous Use,” accessed 18 September 2026.

Mesenchymal stromal cell, abbreviated MSC. A cell type that can be obtained from several tissues, including bone marrow and fat. Where to look: FDA’s list of licensed cellular and gene therapy products, and then the indication printed beside any product name you find there. A claim that “MSCs are FDA approved” is a claim about a class, and approval does not attach to a class. What the list contains today, and what any product on it is licensed for, belongs to our approvals page.

Hematopoietic stem and progenitor cells. The blood forming cells, obtained from bone marrow, circulating blood or cord blood. The FDA guidance uses these cells in an example: culturing them under specific conditions to produce terminally differentiated cells “would generally be considered more than minimally manipulated.”

Source: FDA, “Regulatory Considerations for Human Cells, Tissues, and Cellular and Tissue-Based Products: Minimal Manipulation and Homologous Use,” accessed 18 September 2026.

Chondrocytes. Cartilage cells. Where to look: the same licensed product list, and the indication beside any name you find there. Our approvals page quotes one such indication in full and shows how narrow it is.

Blood-derived terms

Platelet rich plasma, abbreviated PRP. A preparation made by processing a sample of a person’s own blood to concentrate platelets. It is produced at the point of care by a centrifuge and a disposable kit.

Which framework it is not in, and FDA says so directly.

“PRP is blood taken from an individual and given back to the same individual as platelet rich plasma. PRP is not an HCT/P because it is a blood product. Therefore, the compliance and enforcement policy did not apply to PRP or other blood products.”

Source: FDA, “Questions and Answers Regarding the End of the Compliance and Enforcement Policy for Certain Human Cells, Tissues, or Cellular or Tissue-based Products.” Page stamp: Content current as of: 07/09/2021. Accessed 18 September 2026.

So the four criteria are the wrong branch for PRP, and the exclusion above is where that comes from rather than being our reading of it.

Where to look, and this one has a record you can open. The record to look for is a device clearance for the separation equipment, not an approval of the preparation. Clearance records are public: each has a number beginning with K, and each states what the device was cleared to do. A clearance for the machine is not an approval of what is injected, and it does not establish that any particular use of the preparation has been reviewed by FDA.

So the question to ask is what exactly was cleared, and under which number. A clearance number is short and free to look up.

Our approvals page works through one such record in full, including the trap that the record’s classification today is not the classification that governed the decision when it was made.

A2M, alpha-2-macroglobulin. A protein, offered in this field as a concentrated preparation made from a person’s own blood. We did not open a source that defines it, so read that sentence as a description of how the term is used rather than as something we established, and note that nothing below depends on it. What the routing runs on is the description you are given, not ours.

Where to look, and what we could establish. We read FDA’s consumer page on regenerative medicine therapies in full. It enumerates the materials it is describing:

“These unapproved products, whether recovered from your own body or another person’s body, include stem cells, stromal vascular fraction (fat-derived cells), umbilical cord blood and/or cord blood stem cells, amniotic fluid, Wharton’s jelly, ortho-biologics, and exosomes.”

Source: FDA, “Important Patient and Consumer Information About Regenerative Medicine Therapies,” accessed 18 September 2026.

This term is not in that list, and in the FDA sources we opened for this page we did not find a current FDA position naming it. That is a statement about what we read, not about everything FDA publishes. And the absence is not a favourable finding, nor an unfavourable one. What it means practically: the position for an A2M preparation has to be worked out from what the preparation actually is, not from a statement about A2M.

And there is one thing we can say about the route, which turns on what you are told. If what you are being offered is described to you as a concentrate prepared from your own blood or plasma, then the starting point is the blood exclusion quoted above and not the four criteria, because blood is outside the HCT/P definition by the same provision that puts PRP outside it. That inference is safe because it rests on the description you were given rather than on any claim of ours about what A2M is. If the preparation is described some other way, the exclusion may not apply, and the question below is the one to work through.

What has to be established first, in this order: what the preparation physically is, how it was processed, what device was used to produce it, and what it is being offered to do. The applicable framework follows from those four answers rather than from the name. If the preparation is described to you using the word ortho-biologic, note that the word is in the list above.

Cell-free terms

Exosome. Small vesicles released by cells, prepared as a product without the cells themselves. This is the one material in this glossary for which FDA states a position in a single sentence:

“Exosome products are also regulated by FDA. As a general matter, exosome products intended to treat diseases or conditions in humans require FDA approval. There are currently no FDA-approved exosome products.”

Source: FDA, “Consumer Alert on Regenerative Medicine Products Including Stem Cells and Exosomes,” accessed 18 September 2026.

Secretome. Used in this field for a cell-free preparation of what cells release into the medium around them, exosomes among it. That is a report of how the word is used in marketing, not a definition we sourced, and the distinction matters here more than usual: the word describes a mixture, so the useful question is not what secretome means but what is actually in the vial and how it was prepared. Ask for that in writing.

Where to look, and what we could establish. This term does not appear on FDA’s consumer page on regenerative medicine therapies, whose enumeration is quoted under A2M above, and in the documents listed at the foot of this page we did not find a current FDA position naming it either. So the entry that matters is the one next to it: establish whether what you are being offered is, or contains, an exosome product, because the sentence quoted immediately above then applies to it. Ask for that in writing, using the word exosome, and see which answer comes back.

Birth-tissue terms

Umbilical cord blood. Blood collected from the umbilical cord and placenta after birth, containing blood-forming stem cells. Where to look: FDA’s list of licensed cellular and gene therapy products, where cord blood products appear under the generic name HPC, Cord Blood and under trade names. Which products are on that list, what each is licensed for, and how an older FDA page describing this material compares with the current list are all questions our approvals page answers, because that page owns the record and this one owns the word.

Wharton’s jelly. The gelatinous tissue inside the umbilical cord, as the term is ordinarily used; we did not open a source defining it and the route below does not rest on the phrase. Where to look: it is named directly in the FDA enumeration quoted under A2M above, which describes the products in that list as unapproved. Beyond that enumeration, whether a specific preparation is an HCT/P is worked out from how the tissue was processed and what it is intended to do, which is what the four criteria address.

Amniotic fluid. The fluid surrounding a fetus during pregnancy, collected at delivery. It is named in the same FDA enumeration as Wharton’s jelly, and that is where the similarity ends. The two do not share a regulatory route, and reading them as one category sends the question down the wrong branch before it has been asked properly.

FDA’s guidance places secreted body fluids outside the HCT/P definition, and then draws a second line inside the material itself:

“Secreted body fluids (e.g., amniotic fluid) are generally not considered HCT/Ps. Cells from secreted body fluids are generally considered HCT/Ps, and the definition of minimal manipulation for cells or nonstructural tissues would apply.”

Source: FDA, “Regulatory Considerations for Human Cells, Tissues, and Cellular and Tissue-Based Products: Minimal Manipulation and Homologous Use,” accessed 18 September 2026.

Read both halves. The fluid is generally outside; cells taken from the fluid are generally inside. So the first question about an amniotic product is what is actually in the vial, and a product name will not tell you.

One further distinction, from the same guidance: amniotic membrane is a different material again, listed there among structural tissues alongside bone and skin. Membrane, fluid and cells from fluid are three things, and a preparation described only as amniotic has not told you which of the three it is.

Source for both terms appearing in the enumeration: FDA, “Important Patient and Consumer Information About Regenerative Medicine Therapies,” accessed 18 September 2026, quoted in full under A2M. The regulatory routing of the two is sourced separately above, because it is not the same for both.

Proprietary and brand terms

Some of what you will hear is not a material name at all. It is a trade name, a process name, or a name a specific supplier has given to its own preparation.

A brand name identifies a branded product or offering, and it can belong to a marketer, a distributor or a licensee rather than to whoever manufactures the thing. It does not by itself tell you what the material is, how it was processed, who made it, or where it sits in the rules. When you encounter one, the useful move is to ask which of the material terms above it corresponds to, and then to run the check on that.

Regulatory position note: this page does not list individual brand or product names. Position depends on the specific product, and a general statement about a brand would be unreliable.

Terms that describe a process, not a product

The three terms below are described as they are used in conversation and marketing. Two of them are not regulatory classifications at all. The first one is the exception and its entry says why.

Regenerative. On its own, in marketing, a description of intent rather than a classification: it tells you what an approach aims to do, not what is being administered.

But the longer phrase does have a legal definition, and it is narrower than the marketing use. FDA states it:

“Regenerative medicine therapies (RMTs) are defined in section 506(g)(8) of the Food Drug & Cosmetic Act as including cell therapies, therapeutic tissue engineering products, human cell and tissue products, and combination products using any such therapies or products, except for those regulated solely under section 361 of the Public Health Service Act”

Source: FDA, Resources Related to Regenerative Medicine Therapies. Accessed 18 September 2026.

Read the final clause, because it is the surprising part. The statutory term excludes products regulated solely under section 361. So a preparation can be described as regenerative in an advertisement and, if it meets the four criteria and is regulated solely under section 361, sit outside the statutory definition of a regenerative medicine therapy at the same time. All of that can be true together, and none of it is a statement about how much of the field is in that position, which we have not measured and are not claiming.

What follows for you is a question rather than a conclusion: when the phrase is used, is it being used in the marketing sense or the statutory one? Where to look: the four criteria, which is what decides whether the section 361 category applies at all.

Biologic. A broad regulatory term covering a range of products derived from living sources. It is accurate and it is wide, so on its own it narrows very little.

Orthobiologic. An informal term for biological materials used in musculoskeletal settings. It is a usage description, not a regulatory classification, and the underlying material term is the one that carries the position.

What to do with this page

You now have a material name. Two things follow from it and neither is a judgment about treatment.

First, whether an approved product exists under that name and what its licensed use is. Second, if there is no approved product, which regulatory category the preparation falls into and why.

Where to go from here

Two pages on this site take the next steps in order: What Is and Is Not FDA Approved in Regenerative Medicine, then The Four Criteria and the Exceptions That Decide How an HCT/P Is Regulated.

Before you leave this page: ask for the material name in writing. The word used in conversation and the word printed on a consent document may not be the same, and the written one is the one you can check.

What this does not mean

Nothing on this page indicates that any material is effective, safe or appropriate for any person. Where a term carries no regulatory position note, that means we could not find one in the sources listed at the foot of this page, not that the position is favourable. This is a vocabulary page. It is not medical advice and it does not evaluate any treatment, product, practice or individual case.

Seven documents, six FDA pages and one section of the regulation. Every quotation above comes from one of these. The material enumeration on the fifth is what several entries rest on, so if you open one thing, open that and read the list of materials for yourself. If you open two, make the second one the regulation, because it is the document that says which materials are outside the framework entirely.

The evidence universe for this page, stated so the absence claims can be read correctly. The seven documents above are what we opened for this page. Where an entry says we did not find a current FDA position naming a term, that means we did not find one in the sources listed at the foot of this page; it is not the result of an exhaustive search of everything FDA publishes. A reader with a different starting point may find something we did not, and that is a better outcome than us implying a completeness we did not achieve.

And one thing the enumeration above does not do. Four entries on this page rest on the FDA consumer page quoted under A2M, and what that page establishes for them is narrow: it establishes that FDA names the material. It does not define the term, it does not assign the material to a regulatory category, and it does not settle which framework a particular preparation sits in. Where this page states a definition without a source beside it, that is a report of how the word is used rather than something we established, and it is marked as such in the entry. Every regulatory route on this page is sourced separately from the definition it sits next to, because the two are not the same kind of claim.

Written and fact-checked against the sources above on 18 September 2026. No independent expert review has taken place yet, and this page says so rather than implying one. This page is reviewed every three months, and also whenever any of the sources listed above changes. The shortest interval in this set sits here for a specific reason: several entries point at FDA’s licensed product list, the enumeration quoted under A2M is what four of the birth-tissue and blood-derived entries rest on, and the routing of three materials now rests on two exclusion texts rather than on the four criteria. A single change to any of those would change what this page should say.

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