The short answer
Platelet-rich plasma, or PRP, is made from your own blood in the clinic during the same visit as the injection. A small tube or syringe of blood is spun in a centrifuge, the layers separate by weight, and the plasma containing a concentrated share of platelets is drawn off and injected into the treatment area.
What surprises most people is how much that “concentrated share” can vary. Different kits, spin settings and volumes of blood produce PRP with very different platelet counts and cell content. That variation is one of the main reasons studies on PRP for hair, joints and erectile function so often disagree.
How PRP is made, step by step
The basic method is the same everywhere, even when the details differ.
- Blood draw. A small amount of blood is drawn from a vein in your arm into a tube or syringe that contains an anticoagulant, so it does not clot.
- First spin. The tube goes into a centrifuge. Spinning separates blood by density: red cells sink to the bottom, a thin whitish layer of white cells and platelets forms above them, and yellow plasma sits on top.
- Separation. The plasma, along with the platelets near the boundary, is drawn off. Which part is collected, and how close to the red cell layer the collection goes, changes what ends up in the syringe.
- Optional second spin. Some protocols spin the plasma again to pack the platelets into a smaller volume, then remove the platelet-poor plasma on top.
- Optional activation. Some protocols add an agent that activates the platelets before injection; others rely on the body to do it.
- Injection. The PRP is injected into the scalp, tendon, joint or other treatment area, often with numbing first.
The American Academy of Orthopaedic Surgeons explains that PRP is plasma with many more platelets than normal blood, with platelet and growth factor concentrations that can be 5 to 10 times greater than usual, achieved by spinning the blood down in a centrifuge. For hair, the American Academy of Dermatology describes a small blood draw processed in a machine that separates red cells from the plasma, with the injection itself taking about 10 minutes.
Why platelet concentration varies so much
Because almost every step has a setting, and every setting changes the product. A 2019 systematic review compiled data on 33 commercial PRP systems and protocols and found that both the preparation methods and the final concentrations varied widely. Platelet concentration was directly linked to two things: how much blood was collected and how much centrifugal force the device used.
| Variable | How it changes the PRP |
|---|---|
| Volume of blood drawn | More blood can yield more platelets in the final product |
| Centrifuge force and time | Changes how cleanly platelets separate from other cells |
| One spin or two | A second spin packs platelets into a smaller volume |
| Where the sample is drawn from | Collecting near the red cell layer adds white cells and some red cells |
| Activation | Changes when growth factors are released |
| Your own blood | Your baseline platelet count sets the starting point |
White blood cell content is a big part of the story. The AAOS describes leukocyte-rich PRP as having a white cell count above that of whole blood, and leukocyte-poor PRP as having less. The two are prepared differently and may behave differently in tissue, which is why researchers track them separately.
Why that makes studies hard to compare
If two studies both say they used “PRP,” they may have injected quite different products. The authors of the PAW classification pointed out that protocols vary widely between studies and are often poorly documented, making results difficult to compare or repeat. Their system describes any PRP by three features: the absolute number of platelets, how the platelets were activated, and whether white cells are present.
An earlier classification by Dohan Ehrenfest and colleagues sorted platelet concentrates into four families, pure PRP, leukocyte- and platelet-rich plasma, and two fibrin-based forms, arguing that each method produces a product with different biology and possible uses. The 2019 review reached the same conclusion more than a decade later and called for standardized reporting.
This matters when you read about results. Evidence for PRP in hair loss and some tendon problems is mixed to promising, and the International Society for Sexual Medicine describes the evidence for erectile dysfunction as mixed, with some studies showing improvement and others suggesting PRP may not beat placebo. Part of that inconsistency likely reflects different preparations, not just different patients. PRP is not FDA-approved for hair loss or erectile dysfunction.
Questions to ask before a PRP treatment
You do not need to become an expert in centrifuges, but a few questions tell you a lot about a clinic’s approach:
- Which system or kit is used, and how much blood is drawn?
- Is it a single or double spin?
- Is the PRP leukocyte-rich or leukocyte-poor, and why that choice for this area?
- Is an activating agent used?
- How many sessions are planned, and how far apart?
- What does the evidence show for this specific use, and what does it not show?
For hair, the AAD describes a typical schedule of monthly sessions for the first three months, then once every three to six months, and notes that PRP needs maintenance rather than being a permanent fix. Our guide to what to expect at a PRP hair session walks through the visit itself.
How Ultimate Male prepares and uses PRP
At our San Gabriel and Downey clinics, PRP injections are prepared from your own blood during the same visit and used in three areas: hair restoration for thinning scalp hair, PRP for erectile dysfunction in a P-Shot style approach, and PRP for tendon and joint repair. Each starts with an assessment of whether PRP fits your situation and an honest conversation about the evidence for that specific use.
The procedure is done in clinic with numbing and little to no downtime. Ultimate Male is direct-pay with itemized receipts and financing through CareCredit, Prosper Healthcare Lending or Afterpay. To ask whether PRP makes sense for you, call 626-319-5261 for the free 10-minute phone call.
