PRP Injections: What Is Platelet-Rich Plasma and How Does It Work?

A simple guide to what PRP is, how it is made from your own blood, and why the details of the preparation matter.

Key message: PRP is not a single standardised drug. It is a category of autologous blood-derived preparations, and two treatments both called “PRP” can be biologically very different. [1,2]

What is PRP?

Platelet-rich plasma, or PRP, is prepared from your own blood. Blood is collected into a sterile system and processed, usually by centrifugation, to separate red blood cells from plasma and platelet-containing fractions. A selected portion is then injected into a defined target such as a joint, tendon, ligament or other structure.

Platelets are best known for their role in clotting, but they also contain and release signalling molecules that participate in inflammation, tissue repair and cell-to-cell communication. PRP is intended to place a concentrated biological signal at a selected site. It is not an instant painkiller and it is not a stem-cell treatment.

Why “PRP” does not tell you everything

The name does not tell you the blood draw volume, platelet concentration, final injected volume, total platelet dose, white-cell profile, red-cell contamination, anticoagulant, activation method or processing system. These variables are important because they change the biological product being injected. [1,2]

Platelet concentration: how many platelets are present in each unit of PRP.
Injected volume: how much PRP reaches the target.
Total platelet dose: the total number of platelets delivered, usually expressed in billions.
Cellular composition: the amount and type of white blood cells and any residual red blood cells.
Preparation quality: how the blood is collected, anticoagulated, separated, handled and delivered.

What is PRP used for?

PRP is used most commonly in musculoskeletal medicine for selected joint and soft-tissue conditions. The evidence is not equal for every diagnosis. Knee osteoarthritis has one of the largest clinical evidence bases; results for tendons, ligaments, muscle, nerves and spinal applications vary by condition and protocol. [3-7]

The important starting question is therefore not simply “Does PRP work?” but “Is PRP appropriate for this diagnosis, with this biological preparation, delivered to this target?”

Related Patient Guides

PG8002 – Does PRP Work? What the Current Evidence Shows
PG8003 – Why Medicare Does Not Rebate PRP Injections in Australia
PG8004 – How to Prepare for PRP: Supporting Your Healing Potential Before Treatment
PG8005 – PRP Aftercare: Supporting Healing After Your Injection
PG8006 – PRP Platelet Dose and Blood Draw Volume: Why the Numbers Matter
PG8007 – How to Choose a PRP Provider: Questions to Ask Before You Book
PG8008 – Why Image-Guided PRP Matters: Ultrasound and CT Guidance
PG8009 – PRP Injection Accuracy and Documentation: Recording Final Needle Position
PG8010 – How Many PRP Injections Will I Need? One Treatment vs a Series

Frequently Asked Questions

For other FAQs please visit our FAQs page

Is PRP the same as a blood transfusion?

No. PRP is autologous: it is prepared from your own blood and returned to you as a concentrated blood-derived product.

Is PRP a stem-cell treatment?

No. Standard PRP is a platelet-rich blood product. Some white blood cells may also be present depending on the preparation, but PRP should not be described as a stem-cell therapy.

Does a higher platelet concentration always mean better PRP?

No. Concentration is only one variable. The total dose depends on both concentration and injected volume, and the optimal formulation may differ between conditions.

How long does PRP take to work?

PRP is generally assessed over weeks to months rather than hours or days. Some patients notice an early pain flare before improvement. Recovery depends on the tissue, severity, loading and rehabilitation.

This guide provides general information only. PRP suitability, medication changes, dosing, procedure choice and rehabilitation require individual clinical assessment.

Important: General information only. Your procedure, medication instructions, transport requirements and aftercare may differ.

PATIENT GUIDE • PG-8001 [Patient information: A simple guide to what PRP is, how it is made from your own blood, and why the details of the preparation matter.]