Research brief · 2026-09-09
What Is the Evidence for PRP in Tendon Injury?
Platelet-rich plasma, or PRP, is made by drawing a person's own blood, spinning it to concentrate the platelets, and injecting the result into an injured tendon. It has one of the most extensively trialled records of any regenerative treatment for tendon injury, and the results are genuinely mixed.
The single strongest piece of evidence is Kearney's 2021 multicenter trial in JAMA. Across 24 sites, 240 adults with chronic midportion Achilles tendinopathy were randomized to one PRP injection or a sham injection, a needle under the skin but not into the tendon. At six months the VISA-A function score, where a 12-point change is considered clinically meaningful, was 54.4 with PRP and 53.4 with sham. The trial's conclusion was that PRP did not reduce Achilles tendon dysfunction compared with placebo.
Masiello's 2022 systematic review in Blood Transfusion widened the lens, pooling 33 randomized trials and 2,025 patients across six tendon conditions. For tennis elbow, plantar fasciitis, Achilles, rotator cuff and patellar tendinopathy, there were no clear differences between PRP and comparators at any follow-up. The one exception was carpal tunnel syndrome. The reviewers rated the overall certainty of evidence low or very low. Against corticosteroid injections specifically, Ye's 2025 meta-analysis found PRP had a mid-term edge at three to six months, with long-term efficacy unverified.
The picture changes when PRP is used during surgery rather than injected alone. Ryan's 2021 meta-analysis in Arthroscopy pooled 17 randomized trials of arthroscopic rotator cuff repair. The imaging-confirmed retear rate was 19.3 percent with PRP augmentation versus 25.4 percent without, and pure PRP without added white cells showed the strongest effect.
The limits are unresolved. No study explains why standalone injections look weak while surgical augmentation looks stronger, few trials compare PRP formulations, and most follow-up stops well before a year. No trial has identified which patients respond. Anyone considering PRP should discuss it with a physician or orthopedic specialist.
Sources
- Kearney RS et al. Effect of Platelet-Rich Plasma Injection vs Sham Injection on Tendon Dysfunction in Chronic Midportion Achilles Tendinopathy
- JAMA 2021
- Masiello F et al. Ultrasound-guided injection of platelet-rich plasma for tendinopathies: a systematic review and meta-analysis
- Blood Transfusion 2022
- Ryan J et al. Platelet-Rich Product Supplementation in Rotator Cuff Repair Reduces Retear Rates and Improves Clinical Outcomes: A Meta-analysis
- Arthroscopy 2021
- Ye Z et al. Platelet-rich plasma and corticosteroid injection for tendinopathy: a systematic review and meta-analysis
- BMC Musculoskeletal Disorders 2025
Peptide Proof reports what studies found. We do not give medical advice, dosing guidance, or treatment recommendations.