After a PRP injection in the shoulder, most people have soreness for 2 to 5 days, sometimes more pain than before the shot. Any benefit, if it comes, usually builds slowly over 4 to 12 weeks. The research on PRP for shoulder problems is mixed: some studies show modest benefit, others show no clear advantage over other treatments. PRP is often not covered by insurance, so ask about cost and evidence before you agree.
PRP (platelet-rich plasma) is most often offered for rotator cuff tendinopathy, partial rotator cuff tears, and sometimes alongside rotator cuff repair or for shoulder arthritis. What follows covers what to expect afterward and the activity guidance most clinics give.
Key takeaways
- What it is: a concentrate of platelets from your own blood, injected into or near the painful tendon or joint.
- Soreness: a few days of increased pain after the injection is common.
- Slow onset: any change tends to appear over weeks, not days.
- Mixed evidence: studies on PRP in the shoulder disagree, and preparations vary between clinics.
- Cost: PRP is often not covered by health insurance in the US and many other countries.
- Anti-inflammatories: many clinics ask you to avoid them for a period before and after.
What the injection is and why it is used
A small amount of your blood is drawn and spun in a centrifuge to separate out a layer rich in platelets. Platelets carry growth factors involved in tissue healing. The idea is that putting a concentrated dose into a struggling tendon may encourage a healing response.
The honest picture is uncertain. Studies use different preparations, volumes and injection sites, and results range from modest benefit to no difference. Major orthopedic and sports medicine groups describe the evidence for shoulder use as limited or still developing. Some people report improvement. It is hard to know in advance who will.
Because many insurers class PRP as investigational, people often pay the full cost themselves, which can run to several hundred dollars or more per injection. It is reasonable to ask the clinic what results they expect, what the total cost is, and whether more than one injection is planned.
Day by day: the first week
- Day 0: the shoulder may feel full, tight or achy. Rest it from effort for the day but keep it gently moving. Many clinics allow a cold pack for short periods.
- Days 1 to 3: soreness often peaks here, and it can be more than your usual pain. This is commonly linked to the inflammatory response PRP is meant to start. Ask your clinic which pain relief to use, since many advise acetaminophen (paracetamol) rather than anti-inflammatories such as ibuprofen.
- Days 3 to 7: soreness usually eases. Light daily tasks and gentle range-of-motion exercises are usually allowed. Avoid lifting, pushing and overhead effort.
Weeks 2 to 6
- Weeks 1 to 2: most protocols keep you to light use and gentle movement. Some ask you to wear a sling for a day or two, especially after an injection into a tear.
- Weeks 2 to 6: a graded strengthening program usually starts or resumes, building slowly. Loading the tendon is part of the reason for the injection, so stopping exercise altogether is rarely advised.
- Weeks 6 to 12: this is when any benefit is usually judged. Return to sport, gym work or heavy manual work is typically staged over this period, guided by your clinic and physical therapist.
Whatever is injected, the tendon still has to be loaded, slowly and regularly, to get stronger.
How long the effect usually lasts, and how to use the window
When people do report benefit from PRP, studies often follow them for 6 to 12 months. There is no firm figure for how long it lasts, because results vary so much. What is clearer is that exercise carries much of the long-term change in tendon problems. The weeks after the injection are a time to follow a structured, progressive program rather than wait to see if the shot works.
How many injections are usually considered
Practice varies. Some clinics give a single injection, others a series of two or three a few weeks apart. Since each one carries a cost, ask before you start how many are planned and what result would lead them to stop. If there is no meaningful change after about 3 months, a further injection is less likely to help, and it is worth reviewing the diagnosis and the rehab plan.
Is this normal?
- Worse pain for a few days: common after PRP and usually settles within the first week.
- Bruising at the blood draw site: common and harmless.
- No change after 2 weeks: expected. Any benefit from PRP is usually slow to appear.
- Stiffness from resting it too much: can happen if the shoulder is kept still for long. Gentle movement each day helps.
Call your local emergency number or go to the emergency department if
- Fainting or collapse: after the blood draw or injection, with chest pain, breathlessness or a racing heart.
- Chest symptoms: chest pain or pressure, breathlessness or sweating with shoulder or arm pain, especially on the left.
See a doctor today if
- Signs of infection: spreading redness, heat, swelling or pus at the injection site, or pain that keeps rising after day 3.
- Fever: 100.4°F (38°C) or higher, or chills.
- Severe new pain: pain far beyond the expected soreness that pain relief does not settle.
Get it checked soon if
- Sudden loss of strength: you cannot lift the arm as well as before, or you felt a pop.
- Soreness past 2 weeks: post-injection pain that has not eased by then.
- Pain or tingling down the arm: symptoms past the elbow may come from the neck.
More on this area: injections for neck and shoulder pain.
Ask about the evidence and the cost first, then plan the exercise that follows.
Written by Louise Yow, Neck & Shoulder Physio.