Stem cells come from three main sources. Embryonic stem cells are taken from early-stage embryos. Adult, or somatic, stem cells are found in tissues such as bone marrow, fat, and umbilical cord. Induced pluripotent stem cells (iPSCs) are ordinary adult cells that have been reprogrammed in a lab.
Nearly every stem cell clinic you’ll come across, whether in the US or abroad, uses adult stem cells, most often a subtype known as mesenchymal stem cells (MSCs). This guide covers all three types, explains what “potency” means, and helps clarify which source your clinic is most likely using.
What a Stem Cell Actually Is
A stem cell is an unspecialized cell that can copy itself and turn into a specialized cell type. Two abilities define it, and an ordinary cell has neither. Self-renewal means it divides to produce more stem cells, so the supply is not used up. Differentiation means it can become a working cell with a job, such as a cartilage, bone, or blood cell.
A skin cell can only make more skin cells. A stem cell sits upstream of that, holding the option to become several things and to keep replacing itself while it does. That is the whole idea, and it is why researchers have pursued stem cells for repairing tissue the body cannot rebuild on its own.
The catch is that having the option is not the same as taking it. A cell injected into a damaged knee can be a genuine stem cell and still fail to become cartilage, which is what the trial evidence on joint injections largely shows. Our mechanism guide covers what researchers now think injected cells actually do.
Where Stem Cells Are Found in the Body
Adult stem cells sit in small reserves inside specific tissues, and each reserve is restricted to the cell types its tissue needs. The NIH’s stem cell basics reference describes them living in a tissue or organ throughout life, and the list is longer than the three sources clinics sell.
| Tissue | What its stem cells make | Can a clinic harvest and inject it? |
|---|---|---|
| Bone marrow | Blood and immune cells, plus mesenchymal stem cells | Yes, by needle into the pelvis |
| Fat (adipose) | Bone, cartilage and fat cells | Yes, by a small liposuction |
| Umbilical cord and placenta | Mesenchymal and blood-forming cells | Yes, from a donor after birth |
| Peripheral blood | Blood-forming cells, after a drug mobilizes them | Yes, in transplant medicine |
| Dental pulp | Tooth and connective tissue cells | Rarely, and mainly for storage |
| Skin, gut lining, muscle, brain | Cells for their own tissue only | No |
The last row is the one clinic marketing tends to blur. Your gut lining and your skin renew themselves constantly from their own stem cells, and neural stem cells exist in the adult brain. None of those reserves can be collected and injected as a treatment. Only the short list at the top reaches a clinic menu: marrow, fat, and donated cord tissue. Our BMAC, adipose and umbilical cord guides cover each one.
Embryonic stem cells
Embryonic stem cells come from the inner cell mass of a blastocyst, an early-stage embryo roughly five days after fertilization, according to the NIH stem cell basics reference. Scientists first developed a method to derive and grow these cells in the lab in 1998. They are pluripotent, meaning they can become nearly any cell type in the body, which makes them scientifically valuable for research into development and disease, but also historically the most ethically and legally debated stem cell source, since deriving them destroys the embryo.
Embryonic stem cells are not what typical joint-injection or IV-infusion clinics use. Their clinical use today is limited mostly to research and a small number of specialized, still-investigational therapies, such as an embryonic-stem-cell-derived islet cell treatment for type 1 diabetes currently in Phase 3 trials.
Adult (somatic) stem cells, the ones clinics actually use
Adult stem cells live within a specific tissue or organ throughout your life and can develop into the specialized cell types of that tissue. They are called multipotent, meaning they can become a limited set of related cell types rather than any cell in the body. Adult stem cells are the source behind the overwhelming majority of stem cell treatments actually offered by clinics today, whether in the US or overseas.
The most commonly used adult stem cells are mesenchymal stem cells (MSCs), which clinics source three main ways:
- Bone marrow, drawn from your pelvis the same day as treatment (see our BMAC guide for how this specific method works).
- Adipose (fat) tissue, removed by a small liposuction procedure, also same-day and from your own body.
- Umbilical cord tissue or blood, donated after childbirth and processed by a lab, meaning these cells come from a donor rather than your own body.
Our mesenchymal stem cell guide covers what MSCs are, how the three sources compare, and what the evidence shows for their use in joints and pain.
Induced pluripotent stem cells (iPSCs)
Induced pluripotent stem cells are ordinary adult cells (usually taken from a skin sample or blood draw) that researchers reprogram in a lab to revert to an embryonic-like state capable of becoming nearly any cell type. Researchers first developed this reprogramming technique in 2006, and it earned its discoverer a Nobel Prize in 2012.
iPSCs sidestep the ethical debate around embryonic stem cells, since no embryo is created or destroyed to make them. But turning an ordinary cell into an iPSC and then into a useful therapy is a complex, expensive lab process, so iPSC-based treatments remain almost entirely investigational rather than something a clinic sells directly to patients today.
Potency: what “can become anything” actually means
You’ll often see stem cells described by how many cell types they can become, a property called potency:
| Potency level | Can become | Example |
|---|---|---|
| Totipotent | Any cell type, plus placental tissue | Cells present only in the first few divisions after fertilization |
| Pluripotent | Nearly any cell type in the body | Embryonic stem cells, iPSCs |
| Multipotent | A limited, related set of cell types | Mesenchymal stem cells (bone, cartilage, fat) |
Clinic-marketed treatments almost always use multipotent adult stem cells, not the pluripotent or totipotent types that appear most often in stem cell research headlines. Marketing that implies a joint injection uses cells that can “become anything” is describing embryonic or iPSC biology, not the multipotent MSCs actually being injected.
Why the source matters for cost and evidence
The stem cell source affects both price and how much evidence exists for a given use. Same-day procedures using your own bone marrow or fat are generally the least expensive, since no lab culturing, donor screening, or long-term storage is involved. Our cost guide breaks down real price ranges by source and joint. Donor-derived umbilical cord products cost more due to processing and screening requirements. Lab-grown embryonic or iPSC-derived products are not sold directly to patients at all; they remain confined to investigational trials.
The bottom line
Stem cells come from three sources (embryonic, adult, and induced pluripotent), but almost every clinic offering a stem cell treatment today, for joints, pain, or elsewhere, is using adult mesenchymal stem cells from bone marrow, fat, or donated umbilical cord tissue. Understanding which source you’re actually being offered helps you read clinic marketing more accurately and ask sharper questions before you pay. See our FDA status guide for how the source affects a treatment’s regulatory status.
Frequently asked questions
What are the three main types of stem cells?
Embryonic stem cells, from the inner cell mass of an early-stage embryo; adult (somatic) stem cells, found in tissues like bone marrow, fat, and umbilical cord blood or tissue; and induced pluripotent stem cells (iPSCs), ordinary adult cells reprogrammed in a lab to behave like embryonic stem cells.
Where do the stem cells used in clinics actually come from?
Almost all stem cell clinics in the US and abroad use adult stem cells, specifically mesenchymal stem cells sourced from a patient's own bone marrow or fat, or from donated umbilical cord tissue. Embryonic stem cells and iPSCs are used almost entirely in research and a small number of specialized, approved therapies, not in typical joint or IV clinic treatments.
What is the difference between totipotent, pluripotent, and multipotent stem cells?
Totipotent cells (found only very early after fertilization) can become any cell type in the body plus the placenta. Pluripotent cells, like embryonic stem cells and iPSCs, can become nearly any cell type in the body but not placental tissue. Multipotent cells, like the mesenchymal stem cells used in most clinics, can become only a limited set of related cell types, such as bone, cartilage, and fat.
Are embryonic stem cells still used today?
Yes, but mainly in research and in a small number of specialized investigational therapies, such as Vertex's stem-cell-derived islet cell therapy for type 1 diabetes. Embryonic stem cell research remains more regulated and ethically debated than adult stem cell research, which is one reason most commercial clinics use adult cells instead.
What are induced pluripotent stem cells (iPSCs)?
iPSCs are ordinary adult cells, usually taken from skin or blood, that scientists reprogram in a lab to revert to an embryonic-like state capable of becoming nearly any cell type. The technique was developed in 2006 and avoids the ethical debate around embryonic stem cells since no embryo is used, but iPSC-based treatments remain mostly investigational.
Does the source of the stem cells affect how much a treatment costs?
Yes. Same-day procedures using your own bone marrow or fat (autologous, adult stem cells) are generally the least expensive since no lab culturing or donor screening is required. Donor-derived umbilical cord products cost more due to processing and screening. Lab-grown products like iPSC or embryonic-stem-cell-derived therapies are investigational and not sold directly to patients at all. See our cost guide for real price ranges.
What is the richest source of stem cells?
It depends which cell type you mean. Fat gives the highest yield of mesenchymal stem cells per gram of tissue, which is why clinics like it. Bone marrow is the standard source for blood-forming stem cells and has the longest clinical record. Umbilical cord blood is dense in blood-forming cells but comes from a donor. No single tissue is richest for every purpose, so a clinic naming one as the best is describing what it sells.
Can you increase the stem cells in your body?
No food, supplement, or protocol has been shown to raise your stem cell count in a way that changes how a treatment works. Exercise and sleep support tissue repair generally, and that is worth doing on its own merits. Products marketed as stem cell boosters or activators are selling an unproven claim, and none is FDA approved for that use. The FDA's consumer information on regenerative medicine is the place to check any specific product.
Does stem cell therapy use your own stem cells?
Sometimes. Clinics source stem cells two ways. Autologous cells come from your own bone marrow or fat and get reinjected the same day. Allogeneic cells come from a donor, most often processed umbilical cord tissue handled in a lab before use. The source matters for more than price. Same-day autologous procedures that are minimally processed sometimes qualify for the FDA's narrower tissue exemption. That exemption skips premarket approval when cells are minimally manipulated and put to homologous use, according to the FDA's own consumer alert. Donor-derived or cultured products fail that test more often and need full FDA approval, which no joint or IV stem cell product currently has. Safety differs too. Your own cells carry no disease-transmission or immune-rejection risk from another person. Donor material depends instead on a clinic's screening and processing controls. Ask a clinic directly which source it uses before you pay, and see our FDA status guide for how that answer shapes the regulatory picture.
Do all stem cells come from fetuses?
No. Only embryonic stem cells come from an early-stage embryo, and almost no clinic offering a joint injection or IV infusion uses that type. The stem cells actually injected at a typical US or overseas clinic are adult (somatic) cells, drawn from a patient's own bone marrow or fat, or from donated umbilical cord tissue collected after a routine birth, not from a fetus. Embryonic stem cells are confined mostly to research and a small number of specialized, still-investigational therapies.
Do clinics use placental stem cells, and are they different from umbilical cord stem cells?
Placental tissue is a donor birth tissue collected after childbirth, and clinics market it as a source of mesenchymal stem cells alongside umbilical cord tissue. No product sourced from placenta or umbilical cord has Food and Drug Administration (FDA) approval for joint, pain, or anti-aging use. These donor-derived products require full FDA approval that no joint or intravenous stem cell product currently holds. They also fail the FDA's narrower "minimally manipulated, homologous use" tissue exemption more often than same-day autologous procedures.
Medical disclaimer. Medical Frontier is an independent educational resource. This page is for general information only and is not medical advice, diagnosis, or treatment, and does not create a doctor–patient relationship. Most regenerative therapies discussed here are not FDA-approved for the uses described and may be offered under limited exemptions or in clinical trials only. Always consult a licensed physician before making any treatment decision.