How Many PRP Injections For The Knee? What The Evidence Shows
For knee osteoarthritis, the best current evidence favours a course of 3 PRP injections over a single injection. A 2025 network meta-analysis of 10 randomised trials and 719 patients found that 3 injections reduced pain and improved function more than 1 injection at 1, 3 and 6 months. Most courses are given 1 to 2 weeks apart under ultrasound guidance, alongside strengthening exercise. PRP does not regrow cartilage, and the evidence overall is favourable but contested, which we explain in full.
Key points
In the 2025 network meta-analysis by Khalilizad and colleagues, 3 injections ranked best for pain and function at every time point, and outperformed a single injection at 6 months.
A 2 injection course did better than 1 on function at 3 months but not on pain at 3 or 6 months.
A 2025 meta-analysis of randomised trials in the American Journal of Sports Medicine concluded that PRP gives clinically significant improvement in knee osteoarthritis, influenced by the platelet concentration used.
At The London PRP Clinic by The Wellness, ultrasound-guided knee PRP is from £595 to £995 per treatment, and a course of 3 is priced at 10 percent off booking the injections individually.
Wondering how many injections your knee needs? Message our doctors on WhatsApp or email team@thewellnesslondon.com.
Why the number of injections matters
PRP works by releasing growth factors and other signalling proteins into the joint, which are thought to calm inflammation in the joint lining and influence the cells around the cartilage. A single injection delivers 1 dose. Repeated injections over a few weeks appear to give a stronger and longer-lasting effect, much as many medicines work better as a course than a single dose.
What the evidence shows
1 versus 2 versus 3 injections
The 2025 network meta-analysis in the Journal of Orthopaedic Surgery and Research pooled 10 randomised trials with 719 patients and compared 1, 2 and 3 PRP injections for knee osteoarthritis. At 1 month, 3 injections were most effective for both pain and function, and both 2 and 3 injections beat 1. At 3 months, 3 injections beat 1 on pain, and both 2 and 3 beat 1 on function, with 3 ranked best. At 6 months, 3 injections beat 1 on both pain and function. No group had major side effects that stopped treatment. The authors concluded that higher-dose PRP, particularly 3 injections, gave superior results.
Platelet concentration
A 2025 meta-analysis of randomised trials by Bensa and colleagues in the American Journal of Sports Medicine concluded that the improvement from PRP in knee osteoarthritis is clinically significant and influenced by the platelet concentration used. In other words, how the PRP is prepared matters as well as how many injections you have. See PRP vs PRF, and how preparation decides your result.
The other side of the evidence
A well-conducted 2021 randomised trial in JAMA by Bennell and colleagues found a course of PRP injections no better than saline placebo at 12 months. Meta-analyses comparing PRP with hyaluronic acid favour PRP, so we describe the evidence as favourable but contested, and explain both sides before anyone decides. Our full comparison is PRP vs hyaluronic acid.
Want an honest view of whether PRP suits your knee? Ask our doctors on WhatsApp.
How a knee PRP course works
Before the first injection
You are assessed by a doctor who examines the knee, hip and the way you walk, and reviews the knee with ultrasound. X-ray or MRI is arranged at the London centre best equipped for that question if you do not already have recent imaging. This confirms the knee has osteoarthritis rather than a meniscus or tendon problem, which would change the plan. See PRP for meniscus tear.
The course
Most courses involve 3 injections given 1 to 2 weeks apart. Each injection uses fresh PRP prepared from your own blood to the same validated protocol and is given under ultrasound guidance. Each appointment takes 45 to 60 minutes, and you walk out afterwards.
Between and after injections
The knee may ache for 2 to 3 days after each injection. Avoid anti-inflammatory painkillers for around 2 weeks after each one unless your doctor advises otherwise. Keep up a strengthening programme, which remains the foundation of treatment for knee osteoarthritis.
Reviewing the result
Improvement usually builds over 6 to 12 weeks after the course. We review pain and function against your starting point at set points and advise on a top-up if and when it is needed.
Who a course suits
A course of 3 is a reasonable choice if
You have mild to moderate knee osteoarthritis confirmed on examination and imaging. You want a treatment from your own blood that leaves nothing permanent in the knee. You are prepared to keep up strengthening exercise.
Another route may be better if
Your knee locks or gives way. You have severe arthritis with pain at rest and at night, where a surgical opinion is the right next step. You would prefer a single permanent injection, compared in Arthrosamid vs PRP. Our guide for younger patients is too young for a knee replacement, and every knee option is compared in knee injections London.
What it costs
Specialist London clinics list knee PRP from £660 to £1,095 per injection, so a course of 3 can reach £1,980 to £3,285 before consultation and imaging. Arthrosamid typically costs £2,000 to £3,500 per knee.
At The London PRP Clinic by The Wellness, there are 3 ways to begin.
The diagnostic package, from £695, covers assessment, imaging and blood tests, and gives you a written recommendation whatever you decide.
A single ultrasound-guided knee PRP injection is from £595 to £995.
A course of 3 injections is priced at 10 percent off booking them individually, with the exact figure confirmed in writing before you commit. More detail is in joint PRP cost in London.
Ask what your knee course would cost. Message us on WhatsApp.
Why people choose The London PRP Clinic by The Wellness
Every treatment is performed by a GMC-registered doctor, and no clinician treats a patient here until they have completed 100 supervised treatments. Every knee injection is ultrasound guided, every injection in a course uses the same validated preparation, and every option is weighed at assessment, including those we do not provide. We also train other doctors in ultrasound-guided joint PRP through our Academy.
We see patients across our London clinics, including 10 Portman Square in Marylebone and The Wellness at The Light Centre in Belgravia. Across our work we report an 87 percent patient success rate and more than 187 five-star reviews. The evidence across conditions is in PRP success rates, and every treatment we offer is in PRP treatment London.
Book your knee assessment. Message us on WhatsApp, email team@thewellnesslondon.com, or call +44 20 3951 3429.
Frequently asked questions about knee PRP injections
How many PRP injections do I need for my knee?
The best current evidence favours a course of 3. A 2025 network meta-analysis of 10 trials found 3 injections reduced pain and improved function more than 1 at 1, 3 and 6 months.
How far apart should knee PRP injections be?
Most courses give 3 injections 1 to 2 weeks apart, with a review of the result over the following 6 to 12 weeks.
Is 1 PRP injection enough for knee arthritis?
It can help, but the 2025 network meta-analysis found a single injection was outperformed by 3 injections at every time point.
How long does knee PRP last?
In people who respond, benefit typically lasts several months to a year, and a top-up course can be considered when symptoms return.
How much does a course of knee PRP cost in London?
Specialist London clinics list knee PRP from £660 to £1,095 per injection. At The London PRP Clinic by The Wellness, a single injection is from £595 to £995, and a course of 3 is priced at 10 percent off booking individually.
Does PRP regrow knee cartilage?
No. PRP aims to reduce pain and improve function. It has not been shown to regrow cartilage.
References
Khalilizad M, Emadian ST, Marzban Abbas Abadi M. Comparative efficacy of different doses of platelet-rich plasma injection in the treatment of knee osteoarthritis. A systematic review and network meta-analysis. Journal of Orthopaedic Surgery and Research. 2025;20:221. Read the study
Bensa A, Previtali D, Sangiorgio A, Boffa A, Salerno M, Filardo G. PRP injections for the treatment of knee osteoarthritis. The improvement is clinically significant and influenced by platelet concentration. A meta-analysis of randomized controlled trials. American Journal of Sports Medicine. 2025;53(3):745-754. Read the study
Bennell KL, Paterson KL, Metcalf BR, et al. Effect of intra-articular platelet-rich plasma vs placebo injection on pain and medial tibial cartilage volume in patients with knee osteoarthritis. The RESTORE randomized clinical trial. JAMA. 2021;326(20):2021-2030. Read the study
This article is for information and does not replace personal medical advice. All treatments at The London PRP Clinic by The Wellness are performed by GMC-registered doctors. Written and medically reviewed by the clinical team at The London PRP Clinic by The Wellness. Last updated October 2026.