PRP is not stem cells. They are two distinct treatments that work in fundamentally different ways, even though both fall under the umbrella of “regenerative medicine” and are sometimes marketed interchangeably. PRP (platelet-rich plasma) is a concentrate of platelets and growth factors derived from your own blood. Stem cell therapy uses actual living cells, typically harvested from bone marrow or fat tissue, that can develop into new tissue. The confusion is understandable because clinics often offer both and sometimes combine them, but they are not the same product.
What PRP Actually Contains
PRP is made by drawing a small amount of your blood and spinning it in a centrifuge to separate the components. The result is a concentrated solution rich in platelets, which are the tiny cell fragments that help with clotting and wound healing. When platelets are activated, they release growth factors from internal storage compartments called alpha granules.
These growth factors are the active ingredients. They include proteins that stimulate collagen production, promote new blood vessel formation, encourage cell migration to injury sites, and reduce bone breakdown. PRP also contains signaling molecules called chemokines that recruit your body’s own repair cells to the area. Think of PRP as a chemical signal flare: it doesn’t build new tissue itself, but it tells your existing cells to ramp up their repair work.
Critically, PRP drawn from a standard blood sample does not contain a meaningful number of stem cells. It is classified as a “bio-aggregate of growth factors,” not a cell-based therapy. Any clinic describing a simple blood-draw PRP procedure as “stem cell therapy” is being misleading.
What Stem Cell Therapy Involves
Stem cell treatments use mesenchymal stem cells, which are living cells capable of developing into bone, cartilage, muscle, or fat tissue. The two most common sources are bone marrow (usually aspirated from the hip bone with a needle) and adipose tissue (harvested via a small liposuction procedure). Both harvesting methods are more invasive than the simple blood draw used for PRP.
Once collected, the cells are concentrated and injected into the treatment area. Unlike PRP, which only signals existing cells, stem cells can actually differentiate into the specific cell types needed to repair damaged tissue. They also release their own potent mix of signaling molecules through a process called paracrine signaling, meaning they both build new tissue and recruit additional repair activity from surrounding cells.
How They Work Differently in the Body
The core distinction comes down to stimulation versus regeneration. PRP acts as a biostimulant. It encourages cells already present in an injured area to function more effectively, promoting healing within the tissue’s existing capacity. If the tissue is severely damaged or the local cell population is depleted, PRP’s ability to help is limited because there simply aren’t enough cells left to respond to its signals.
Stem cell therapy, by contrast, introduces new cells that can replace damaged or lost tissue. This makes it a better candidate for degenerative conditions where the body’s own repair mechanisms have been overwhelmed. Stem cells can address structural damage that PRP cannot, potentially offering longer-lasting benefits because the new tissue they generate becomes a permanent part of the body.
That said, PRP and stem cells are sometimes used together. Growth factors from PRP can help transplanted stem cells survive, multiply, and differentiate more effectively at the injection site. Some orthopedic protocols pair a stem cell injection with PRP for this reason.
Cost and Practical Differences
The procedures feel quite different from a patient’s perspective. PRP requires a standard blood draw, about 15 to 60 milliliters depending on the protocol. The blood is processed in the office in roughly 15 minutes, then injected. The whole visit typically takes under an hour. A single PRP session generally costs between $500 and $2,500, and most conditions require a series of two to four treatments spaced weeks apart.
Stem cell harvesting is more involved. A bone marrow aspiration means a needle inserted into the back of the hip bone under local anesthesia, which can cause several days of soreness at the harvest site. Adipose-derived procedures require a small liposuction, with its own recovery period. Processing the cells takes longer as well. A single stem cell treatment session typically runs $3,000 to $8,000 or more, depending on the joint being treated, the severity of damage, and the provider. Neither PRP nor stem cell therapy is routinely covered by insurance.
When Each Treatment Is Used
PRP has found its widest clinical use in mild to moderate soft tissue injuries: tennis elbow, plantar fasciitis, early-stage knee arthritis, rotator cuff tendinopathy, and hair loss. It works best when there is still a healthy cell population in the tissue that can respond to the growth factor signals. For hair restoration specifically, PRP stimulates existing follicular cells to function better, which is why it is most effective in early-stage thinning rather than areas of complete baldness.
Stem cell therapy is typically reserved for more advanced degeneration. Moderate to severe osteoarthritis, cartilage defects, and conditions where tissue has been significantly lost or damaged are more common targets. Because stem cells can differentiate and replace what’s missing, they offer a potential treatment pathway in situations where PRP alone would not be sufficient. Some clinicians describe the relationship simply: PRP optimizes what you have, while stem cells can rebuild what you’ve lost.
Why the Confusion Exists
Several factors blur the line between these treatments. Both are autologous, meaning they come from your own body. Both are injectable. Both are marketed as “regenerative.” And some clinics use the terms loosely, calling any regenerative injection a “stem cell” procedure regardless of what it actually contains. A PRP injection drawn from your arm does not become stem cell therapy simply because growth factors can influence stem cell behavior elsewhere in the body.
If you’re evaluating a clinic, the key question is simple: what is actually being injected? A blood-derived platelet concentrate is PRP. A bone marrow aspirate concentrate or processed adipose tissue containing mesenchymal stem cells is stem cell therapy. They can complement each other, but they are fundamentally different treatments with different biological mechanisms, different price points, and different levels of invasiveness.