PRP Therapy: Uses, Evidence and Limitations
What PRP is
Platelet-rich plasma (PRP) is made by drawing a patient's own blood, concentrating the platelets, and injecting the resulting plasma into an injured or degenerated area — commonly joints, tendons, or skin.
How evidence differs by condition
For knee osteoarthritis, some randomized trials and meta-analyses report PRP outperforming hyaluronic acid injections for longer-term pain and function, while corticosteroid injections tend to act faster but with effects that fade sooner. However, other reviews describe the comparison between PRP and hyaluronic acid as still controversial, and three high-quality trials published in JAMA in 2021 found PRP no more effective than a saline placebo for knee or ankle osteoarthritis or Achilles tendonitis.
For skin and hair applications, early studies are promising but smaller and less conclusive than the joint-injection research.
| Use case | What evidence suggests |
|---|---|
| Knee osteoarthritis vs. hyaluronic acid | Some trials favor PRP long-term; comparison still called controversial |
| Knee/ankle OA & Achilles tendonitis (2021 JAMA trials) | No better than saline placebo in three high-quality trials |
| Skin and hair | Early, promising, but smaller and less conclusive studies |
What remains uncertain
PRP preparation methods vary between clinics and are not standardized, which makes it harder to compare results across studies or guarantee a consistent dose of platelets from one session to the next.
- PRP shows mixed but sometimes favorable results for knee osteoarthritis versus other injections.
- Some well-designed trials have found no benefit over placebo for certain uses.
- Preparation methods are not standardized across clinics, limiting comparability.
- Before any injection procedure if you take blood thinners or have a bleeding disorder.
- If pain worsens or new swelling develops after an injection.
