PRP therapy, short for platelet-rich plasma therapy, is a regenerative treatment that concentrates platelets from your own blood and injects them into injured tissue to accelerate healing. It works in three steps: we draw a small blood sample, spin the sample in a centrifuge to concentrate the platelets, and inject the concentrated platelets directly into the damaged joint, tendon, or ligament. Once injected, the platelets release growth factors that signal your body to repair the injured tissue.
In this article, we explain what platelet-rich plasma is made of, how the growth factors inside platelets trigger tissue repair, what happens during and after the injection, which conditions respond best, how long results take and how long they last, and how PRP compares with cortisone and hyaluronic acid injections.
What Is PRP Therapy?
PRP therapy is a treatment that uses a concentrated dose of your own platelets to speed up the repair of damaged tendons, ligaments, muscles, and joints. The concentration matters. A platelet-rich plasma preparation contains 2 to 10 times more platelets than the same volume of normal blood, according to the Hospital for Special Surgery and the Cleveland Clinic. That concentrated dose delivers a much stronger healing signal to injured tissue than your bloodstream can deliver on its own.
Because PRP therapy comes entirely from your own blood, doctors classify it as an autologous treatment. Autologous treatments carry a very low risk of rejection or allergic reaction, which is one reason PRP has grown so quickly in pain medicine. A large study of United States commercial insurance claims found that the prevalence of PRP injections quadrupled between 2010 and 2020, with annual usage projected to grow another 66% by 2030. That growth reflects a shift in how patients approach chronic pain: away from masking symptoms and toward stimulating actual tissue repair.
What Is PRP Made Of? Plasma and Platelets Explained
PRP is made of two components of your blood: plasma, the liquid portion, and platelets, the cells responsible for clotting and tissue repair. Plasma consists mostly of water and proteins, and it carries red blood cells, white blood cells, and platelets through your body. Platelets, also called thrombocytes, do far more than form clots. Platelets store growth factors, the specialized proteins that direct healing throughout the body.
Research published in Blood Research identifies 7 fundamental proteins inside platelet-rich plasma: platelet-derived growth factor (PDGF), transforming growth factor-beta (TGF-B), vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), and the adhesive proteins fibrin, fibronectin, and vitronectin. These growth factors are the active ingredients of PRP therapy, and their behavior explains how the treatment produces results.
How Does PRP Therapy Work?
PRP therapy works by releasing concentrated growth factors into injured tissue, where those growth factors stimulate the cells that rebuild tendons, ligaments, cartilage, and muscle. When the concentrated platelets reach the injury site and activate, they release their stored proteins directly into the damaged area. The released proteins then recruit repair cells, trigger new blood vessel formation, and increase collagen production, the structural protein your body uses to rebuild connective tissue.
Each growth factor performs a specific job. PDGF activates repair cells and drives the formation of new blood vessels. TGF-B directs long-term healing and tissue remodeling in fibroblasts and stem cells. VEGF stimulates the growth of new blood vessels that deliver oxygen and nutrients to the repair site. EGF promotes cell growth and cell division at the injury. Research by Marx and colleagues, published in Oral Surgery, Oral Medicine, Oral Pathology, measured up to a 30-fold increase in PDGF, a 7-fold increase in TGF-B, and a 10-fold increase in EGF at treatment sites after platelet concentration.
The strength of that signal is why PRP performs differently than injections that simply reduce inflammation. Steroid injections quiet the pain signal for a period of time. Concentrated growth factors change the tissue itself, and changed tissue is what produces durable relief. The change begins with a straightforward in-office procedure.
How Is a PRP Injection Performed?
A PRP injection is performed in three steps: a blood draw, centrifuge processing, and an image-guided injection into the injured tissue. The full visit typically takes about an hour, according to the Cleveland Clinic, and there is no sedation involved, so you can drive yourself home afterward.
- Blood draw. We take a small sample of blood from your arm, similar to a routine lab test. One to a few tubes provides enough volume for most joint and tendon treatments.
- Centrifuge processing. The blood sample goes into a centrifuge, a machine that spins at high speed to separate blood into its components. The spinning isolates the platelets and concentrates them within the plasma.
- Ultrasound-guided injection. We inject the finished platelet-rich plasma directly into the injured joint, tendon, or ligament. Ultrasound imaging guides the needle to the exact site of the damage, which improves accuracy and reduces unnecessary discomfort.
Ultrasound guidance deserves emphasis because placement determines results. Growth factors only repair the tissue they reach, so an injection that lands a centimeter away from a partial tendon tear delivers less benefit than one placed precisely inside it. Precise placement starts before the injection, with how you prepare.
How to Prepare for a PRP Injection
To prepare for a PRP injection, stay well hydrated, eat a normal meal beforehand, and pause anti-inflammatory medications as directed by your provider. Hydration and food matter because the procedure starts with a blood draw, and a hydrated, fed body handles a blood draw without lightheadedness. Anti-inflammatory medications matter for a more interesting reason. Nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen suppress the inflammatory response, and PRP deliberately uses a short, controlled inflammatory response to jump-start healing. Suppressing that response blunts the treatment, which is why providers typically ask patients to stop NSAIDs before treatment. Your provider will also review your health history and any blood-thinning medications, since certain blood conditions can affect candidacy.
Once you are prepared and the platelets are placed, the question becomes what those platelets can actually fix.
What Conditions Does PRP Therapy Treat?
PRP therapy treats tendon injuries, ligament injuries, muscle strains, chronic joint pain, and osteoarthritis, with the strongest research support in the knee and elbow. A 2023 nationwide study published in The Physician and Sportsmedicine found the knee is the most common treatment site, receiving 36.7% of all PRP injections, followed by the shoulder and elbow at 30.5%. The demand tracks the size of the problem: the Centers for Disease Control and Prevention (CDC) reports that 1 in 4 American adults has arthritis, a number projected to reach 78 million by 2040.
The conditions that respond well to platelet-rich plasma share a common trait. They involve tissues with limited blood supply, which heal slowly on their own because repair cells and nutrients reach them slowly. Concentrated platelets bypass that limitation by delivering the healing signal directly. The conditions we treat most often include:
- Knee osteoarthritis, where PRP reduces pain and improves joint function for patients seeking alternatives to surgery
- Tendonitis and chronic tendinosis, including tennis elbow, golfer’s elbow, and Achilles tendon degeneration
- Ligament sprains and partial tears, where growth factors support the repair of overstretched or weakened tissue
- Muscle injuries, such as calf and hamstring strains in athletes and active adults
- Post-surgical recovery, where platelet activity shortens the notoriously long healing timeline of tendon and ligament procedures
The evidence behind these applications keeps strengthening. In tennis elbow patients, a 2025 retrospective study found that 47% reduced their pain scores to 3 or below on a 10-point scale after treatment. For knee pain specifically, a 2025 systematic review in Cureus covering 1,162 patients found WOMAC pain scores dropped an average of 8.5 points at the 6 to 12 month mark, a statistically significant improvement over comparison treatments. At our Tigard clinic, these are exactly the patients we see most: adults with knee arthritis, athletes with stubborn tendon injuries, and people recovering from injuries that never fully responded to rest and physical therapy.
Patients dealing with degenerative joint disease often ask where platelet-rich plasma fits among their options, and the research on osteoarthritis treatment increasingly places it ahead of the older injection types. Whatever the condition, the healing that follows the injection unfolds on a predictable timeline.
How Long Does PRP Therapy Take to Work?
PRP therapy takes 3 to 4 weeks to produce the first noticeable pain relief, and the tissue continues strengthening for 6 to 12 months after the injection. The timeline follows the three natural phases of tissue healing, and knowing the phases keeps expectations accurate.
The first phase is inflammation, which begins immediately and lasts a few days. The treated area feels sore, stiff, or swollen. Soreness at this stage is the treatment working, because the activated platelets are deliberately triggering the inflammatory cascade that recruits repair cells. The second phase is proliferation, which runs from roughly week 1 through week 4. During proliferation, repair cells build new tissue at the injection site, and this is when most patients notice pain beginning to fade. The third phase is remodeling, during which the new tissue matures and strengthens. Remodeling can continue from 6 months up to a year, which means the results you feel at week 6 typically keep improving for months afterward.
What Are the Signs That PRP Is Working?
The signs that PRP is working are a gradual decrease in pain starting around week 3 to 4, improved joint movement, less morning stiffness, and the ability to handle activities that previously caused flare-ups. The improvement curve is gradual rather than sudden, which distinguishes it from a steroid injection’s fast-then-fading pattern. Research supports the slow build: the largest meta-analysis on the topic, covering 42 studies and 3,696 patients in Annals of Medicine and Surgery, found the most significant improvement from PRP arrives at the 6-month mark. If your pain trend line points steadily downward through months 2 and 3, the treatment is doing its job. How quickly and completely that trend develops depends partly on the number of injections in your plan.
How Many PRP Injections Are Needed?
Most patients need 1 to 3 PRP injections, spaced several weeks apart, depending on the severity of the injury and how the tissue responds. A minor tendon injury in a younger patient may resolve after a single session. Moderate knee osteoarthritis more commonly calls for a short series of PRP injections, because each session layers a fresh dose of growth factors onto tissue that is already mid-repair.
The dose inside each injection matters as much as the count. A 2025 meta-analysis of randomized controlled trials published in The American Journal of Sports Medicine found that high-platelet-concentration PRP delivered superior pain relief and more durable functional improvement than low-platelet preparations. Platelet concentration varies with how the blood is processed, which is one reason outcomes differ between clinics using different preparation systems. It is also why we track your progress between sessions and adjust the plan based on how your tissue is actually responding rather than following a fixed formula. Once the series is complete, the natural next question is how long the improvement holds.
How Long Do PRP Results Last?
PRP results last 6 months to a year or longer, and symptoms typically continue improving for several months after the injection, according to the Cleveland Clinic. The durability comes from the mechanism. Because the growth factors rebuild tissue rather than temporarily numbing it, the relief reflects a structural change that persists after the platelets themselves are gone.
Duration is where platelet-rich plasma separates most clearly from older injection options. The 42-study meta-analysis in Annals of Medicine and Surgery found PRP outperformed both hyaluronic acid and corticosteroid injections, with effects sustained through 12 months of follow-up. For knee osteoarthritis specifically, patients who respond well often return for a maintenance injection annually rather than restarting treatment from zero. Long-lasting results, though, only matter if the treatment producing them is safe, and safety is where PRP holds one of its strongest advantages.
Is PRP Therapy Safe?
Yes, PRP therapy is safe for appropriately selected patients because the injection is made from your own blood, which removes the risk of rejection and makes allergic reactions extremely unlikely. The Hospital for Special Surgery notes that side effects are very limited for exactly this reason. As with any injection, a remote risk of infection exists, and clinics manage that risk through sterile preparation protocols and single-use equipment.
What most patients experience after treatment is temporary soreness and mild swelling at the injection site for a day or two. That short flare is the inflammation phase described earlier, the deliberate first step of the healing cascade, and it fades as the proliferative phase takes over. A meta-analysis of 14 randomized controlled trials found PRP did not significantly increase the risk of adverse events compared with other injections, including saline placebo. Before treatment, we review your health history to confirm candidacy, since patients with certain platelet or blood disorders, active infections, or specific medication needs may be better served by a different approach. Safety after the injection also depends on what you do in the days that follow.
What Should You Do After a PRP Injection?
After a PRP injection, rest the treated area for the first few days, avoid anti-inflammatory medications, and return to full activity gradually as your provider directs. Rest during the first 24 to 72 hours protects the platelet concentration while it settles into the tissue and begins releasing growth factors. Light daily movement such as walking is fine for most joint treatments, but high-impact loading of the treated area too early can disrupt the repair process during its most fragile window.
Avoiding NSAIDs after treatment follows the same logic as pausing them before treatment. Ibuprofen, naproxen, and similar medications suppress the inflammatory phase that platelet-rich plasma depends on. For post-injection soreness, acetaminophen and ice used as directed by your provider manage discomfort without interfering with the growth factor cascade.
How Can I Make My PRP More Successful?
You can make your PRP more successful by following the rest and medication guidelines closely, staying hydrated, completing any prescribed rehabilitation exercises, and attending your follow-up visits. Rehabilitation exercises deserve special attention. New tissue built during the proliferative phase organizes itself along the lines of stress placed on it, so a graduated loading program guided by your provider literally shapes stronger, better-aligned tissue. Follow-up visits let us track the repair, time any additional injections correctly, and pair the treatment with complementary options when the injury calls for broader support. Choosing the right treatment pairing raises the final question most patients ask: how does PRP stack up against the alternatives?
How Does PRP Compare to Other Pain Treatments?
PRP compares favorably to cortisone and hyaluronic acid injections in head-to-head research, delivering slower initial relief but stronger and longer-lasting improvement. Each injection type works through a different mechanism, and the mechanism predicts the result pattern. Cortisone suppresses inflammation, hyaluronic acid lubricates the joint, and platelet-rich plasma stimulates tissue repair. The table below summarizes how the three compare on the measures patients care about most.
| Factor | PRP Injection | Cortisone Injection | Hyaluronic Acid Injection |
|---|---|---|---|
| How it works | Growth factors stimulate tissue repair | Suppresses inflammation and pain signals | Lubricates and cushions the joint |
| When relief starts | 3 to 4 weeks, improving for months | Within days | Within 1 to 4 weeks |
| How long relief lasts | 6 to 12 months or longer | Weeks to a few months | Several months |
| Head-to-head evidence | Outperformed both alternatives on pain and function at 6 and 12 months | Faster early relief, weaker long-term results | 2.19x lower odds of a successful outcome versus PRP |
| Source material | Your own blood | Synthetic steroid | Gel compound |
The comparison is not always either-or. Emerging research shows PRP combined with hyaluronic acid outperforms either treatment alone for knee osteoarthritis, pairing the repair signal of platelets with the immediate cushioning of the gel. Patients weighing all of their non-surgical options should also know that dextrose-based prolotherapy targets ligament laxity through a related repair mechanism, and the right choice depends on which tissue is generating the pain.
Is PRP Better Than Cortisone for Arthritis?
Yes, PRP is better than cortisone for arthritis when the goal is lasting improvement, based on current meta-analysis evidence. The 42-study analysis found platelet-rich plasma produced significantly greater reductions in WOMAC and VAS pain scores than corticosteroid injections, with the gap widest at 6 months. Cortisone still wins on speed, delivering relief within days, and it remains useful for short-term flare control. The tradeoff is durability: cortisone’s effect fades within weeks to months, while repeated steroid exposure raises separate concerns about cartilage health over time. For arthritis patients planning years ahead rather than weeks ahead, the repair-based approach holds the stronger evidence.
Which Is Better, Stem Cell Therapy or PRP?
Neither stem cell therapy nor PRP is universally better; PRP delivers concentrated growth factor proteins, while cell-based treatments like MFAT deliver living cells, and the right choice depends on the tissue being treated. MFAT, short for microfragmented adipose tissue, uses fat tissue harvested from your own body through a mini liposuction. The adipose tissue contains mesenchymal cells, actual living cells that can support cartilage-maintaining chondrocytes in ways platelets cannot, at times even donating their energy-producing mitochondria to struggling cartilage cells. For advanced joint degeneration, MFAT injections add a cellular dimension that platelet proteins alone do not provide.
The two approaches also work together. A combination therapy pairs the growth factor signal of platelets with the cellular support of adipose tissue in a single treatment plan, an option we recommend for select patients whose imaging shows both soft tissue damage and cartilage involvement. An evaluation with ultrasound imaging tells us which structure is driving the pain and which biologic, or which pairing, fits the injury.
Frequently Asked Questions
Does Insurance Cover PRP Treatment?
No, insurance does not cover PRP treatment in most cases, because the Food and Drug Administration (FDA) has cleared the equipment used to prepare platelet-rich plasma but has not formally approved the injections for most uses, which classifies the treatment as investigational for coverage purposes. Nationally, a 2023 study in The Physician and Sportsmedicine found PRP costs clustered around $1,000 per injection, with single treatments across the country ranging from several hundred dollars to $2,500 depending on the clinic, the body part, and the preparation method. A consultation is the reliable way to understand what your specific treatment plan would involve.
Does PRP Work for Older People?
Yes, PRP works for older people, including patients in their 50s, 60s, and beyond, because platelets retain their growth factor content throughout adult life. Age matters less than the condition of the joint being treated: earlier-stage arthritis and partial tendon injuries respond better than end-stage joint degeneration at any age. Notably, demand is rising fastest among younger arthritis patients as well, with one national database study finding PRP injections for hip osteoarthritis grew an average of 53% year over year.
Is 2 Sessions of PRP Enough?
Yes, 2 sessions of PRP are enough for many patients, particularly for mild to moderate tendon injuries and earlier-stage joint conditions. Clinical studies have shown pain and function improvements from protocols using one, two, and three injections, and research on two consecutive injections for knee osteoarthritis reported both pain relief and functional gains at one year. The honest answer for any individual depends on injury severity and the response to the first session, which is why we reassess between injections.
How Many Days Should I Rest After PRP?
You should rest the treated area for 1 to 3 days after PRP, which covers the window when the injected platelets are most active and the temporary soreness of the inflammation phase is at its peak. Rest means avoiding strenuous loading of the treated joint or tendon, not total immobility. Most patients return to desk work the same day or the next day, then rebuild activity gradually over the following weeks under their provider’s guidance.
How Soon Can I Walk After a PRP Injection?
You can walk immediately after a PRP injection in most cases, including gentle bending of a treated knee, since normal low-impact movement does not disturb the platelet concentration. Providers typically ask patients to avoid running, jumping, and heavy lifting involving the treated area for the first several days. Walking short distances at an easy pace is generally encouraged because gentle motion supports circulation to the healing tissue.
Is PRP Actually Worth It?
Yes, PRP is actually worth it for patients with the conditions it treats well, based on the strength of the comparative evidence. Meta-analysis data shows higher rates of symptom relief, lower rates of needing a repeat intervention, and 6.19x greater odds of achieving a clinically meaningful pain improvement compared with alternative non-operative treatments. The value calculation is strongest for people who have plateaued with rest, medication, or physical therapy and want to avoid or delay surgery.
The Bottom Line
PRP therapy concentrates the healing machinery your blood already carries and delivers it, at 2 to 10 times normal strength, exactly where injured tissue needs it. The growth factors inside those platelets rebuild tendons, ligaments, and joint tissue over a 3-phase timeline, producing relief that starts within weeks and keeps strengthening for up to a year. The research comparing platelet-rich plasma against cortisone and hyaluronic acid now spans thousands of patients, and it consistently favors the repair-based approach for lasting results.
If chronic joint or tendon pain has kept you from the activities you love, the team at Active Pain Relief in Tigard is happy to talk through whether platelet-rich plasma fits your situation. We offer free consultations with ultrasound evaluation, and you can schedule a visit whenever you are ready to explore your options.
