PRP vs Exosomes vs Stem Cells — What Each One Actually Does
The three terms are used interchangeably in marketing and they should not be. They are different biological products, prepared differently, regulated differently, and supported by very different quantities of evidence. Confusing them is how patients get oversold and how clinicians get into trouble.
The short version
| PRP | Exosomes | Stem cells | |
|---|---|---|---|
| What it is | Autologous plasma concentrated in platelets | Nanoscale vesicles secreted by cells, carrying proteins and RNA | Cells capable of self-renewal and differentiation |
| Source | The patient's own blood | Culture-expanded cells, usually allogeneic | Bone marrow, adipose tissue, cord, or blood |
| Mechanism | Growth factor release; signalling | Cell-to-cell signalling without transferring cells | Signalling, paracrine effect, and in some settings engraftment |
| Preparation | Chairside, same day | Laboratory manufactured | Minimal manipulation to full culture expansion |
| Regulatory position (India) | Autologous blood product | Depends on source and manipulation; usually a new drug | Standard of care only for listed indications; otherwise trial only |
| Evidence base | Largest of the three, and variable by indication | Earliest, mostly preclinical | Strong in haematology, investigational in most other fields |
Platelet-rich plasma
PRP is the patient's own blood, centrifuged so that the platelet fraction is concentrated in a small volume of plasma. Platelets carry a large payload of growth factors, and the reasoning behind PRP is that delivering them into an injured or ageing tissue amplifies the repair signalling already present.
The critical point that most discussions skip: PRP is not one product. Platelet concentration, leukocyte content, activation method, spin protocol and final volume differ enormously between systems, and those differences change the biology. A trial showing benefit with one preparation says relatively little about another. When you read the PRP literature, read the methods section first.
Exosomes
Exosomes are extracellular vesicles, in the region of 30 to 150 nanometres, released by cells as a way of signalling to other cells. They carry proteins, lipids and RNA. The appeal is that they appear to reproduce much of the signalling benefit attributed to stem cells without administering living cells at all — no engraftment, no differentiation, and a different risk profile.
The honest position: the preclinical data are genuinely interesting and the human data are early. Product characterisation is inconsistent across suppliers, and a considerable amount of what is sold as an exosome product has never been properly characterised at all. If you cannot see the isolation method, the particle count and the purity data, you do not know what you are buying.
Stem cells
Stem cells are defined by two properties: they can renew themselves, and they can differentiate. That definition covers a wide range — haematopoietic stem cells, mesenchymal stromal cells, adipose-derived cells, induced pluripotent stem cells — and those types are not interchangeable.
The evidence is not uniform. Haematopoietic stem cell transplantation is decades-old, well-evidenced standard care for a defined list of, mainly haematological, conditions. Most other applications remain investigational, however confidently they are advertised.
What the law says in India
Stem cell therapy in routine practice is permitted only for the indications on the government-approved list; anything outside that list, and not approved by CDSCO or the Department of Health Research, is treated as illegal. Everything else must be conducted as an approved clinical trial under ICMR ethical guidelines. Read the full regulation guide →
How to choose in practice
- Start with the indication and the evidence for that indication, not with the product
- Prefer autologous and minimally manipulated where the evidence is comparable
- Know your preparation in detail — for PRP, know your protocol's platelet concentration and leukocyte content
- Demand characterisation data for any manufactured biologic
- Tell the patient plainly where the treatment sits: established, investigational, or unproven
- Document the consent conversation as carefully as the procedure