What Is The Therapeutic Product In PRP?

Is it platelets? Is it plasma? I suspect the true answer far more complex.

When I first learned about platelet-rich plasma (PRP), the answer seemed obvious.

The clue was in the name.

Platelet-rich plasma.

Surely the therapeutic product must be the platelets.

After all, much of the discussion surrounding PRP revolves around platelet counts. How many platelets are present? How concentrated are they compared with whole blood? How efficiently were they recovered from the blood sample?

Yet the more papers I read, the less certain I become that platelets alone are the answer.

Platelets are undoubtedly important. They contain a remarkable collection of growth factors, cytokines, chemokines and signalling molecules involved in wound healing and tissue repair. When activated, they release many of these substances into the surrounding tissue.

But this immediately raises a question.

If the platelets release their contents and then die, were the platelets themselves the therapeutic product? Or were they simply the delivery vehicle?

Perhaps the true therapeutic product is not the platelet but what the platelet releases.

This idea became even more interesting when I read a recent laboratory study involving PRP.

I have seen studies reporting preservation of platelet viability and biological activity following freezing and thawing.

But in this particular study (2026), the authors stored PRP for up to fifteen days at room temperature before using it in cell culture experiments.

My immediate reaction was simple.

Is that still PRP?

The preparation clearly retained biological activity because important effects were observed in the study. But it made me wonder what exactly was being studied. After fifteen days at room temperature, is the biological product still the same as the freshly prepared PRP I might inject into a patient minutes after centrifugation?

I do not ask this as criticism.

I ask it because I am genuinely curious.

If stored PRP remains biologically active, perhaps intact platelets are not the whole story.

Perhaps growth factors are more important than I previously thought.

Perhaps extracellular vesicles play a larger role than I realise.

Perhaps plasma proteins matter more than I have appreciated.

Or perhaps the therapeutic product is not any single component at all.

This possibility interests me most.

What if PRP behaves less like a drug and more like an ecosystem?

Plasma contains fibrinogen, fibronectin, vitronectin, clotting factors and numerous signalling molecules. Platelets contribute growth factors and cytokines. Extracellular vesicles carry biological messages. The recipient tissue contributes its own cells, inflammatory signals and repair mechanisms.

None of these components act in isolation.

They interact.

Perhaps it is this interaction that creates the biological effect observed clinically.

If that is true, then asking whether the therapeutic product is the platelet or the plasma may be the wrong question.

The therapeutic product may be the biological conversation taking place between all of these elements.

I do not yet know the answer.

In fact, the deeper I look into PRP, the less certain I become that there is a single answer.

But I increasingly suspect that the question itself is worth asking.

What is the therapeutic product in PRP?

The platelet?

The plasma?

The extracellular vesicle?

The growth factor?

Or the interaction between them all?

Authored by Dr Gwen Adey, musing on a Sunday evening, 31st May 2026.