The main side effect of a PRP injection is a sore joint or tendon for a few days, and that soreness is expected rather than a complication. PRP is autologous, made from a sample of your own blood, so allergic reaction and rejection are not on the list of things that can go wrong. Systematic reviews describe complication rates comparable to corticosteroid and saline injections, with transient post-injection pain the most commonly reported event. The rare serious risk is the one any injection carries: infection at the needle site. What separates a good outcome from a bad one is sterile technique, accurate placement, and who is holding the needle.
The honest version of this answer has two halves: the effects that are supposed to happen, and the short list of things that are not. Most pages give you only the first.
What to expect in the first week
Days one to three, the flare
Most patients describe a deep ache in the treated joint or tendon that is worse than before the injection. It commonly peaks in the first 48 hours. This is the most frequently reported event in the published safety literature, and reviews consistently characterize it as transient and self-limiting rather than as a complication. Ice, paracetamol if you need it, and relative rest are the usual answer. The thing to avoid is reaching for an anti-inflammatory out of habit.
Why we ask you to skip the ibuprofen
PRP works by provoking a controlled inflammatory and healing cascade. Non-steroidal anti-inflammatory drugs are designed to blunt exactly that cascade. Taking them through the window when the biologic is doing its work can reasonably be expected to work against the treatment you have just paid for. We will tell you which medicines to hold and for how long, and if you take an anti-inflammatory for another condition, that is a conversation to have before the injection rather than after.
What is genuinely abnormal
Escalating rather than settling pain after the third or fourth day, fever, spreading redness and heat, or drainage from the injection site are not part of the expected pattern. Those are infection questions and they want a same-day telephone call, not a wait-and-see. Infection after an injection is rare, and it is rare precisely because sterile technique and a controlled setting are non-negotiable. Ask any clinic how they handle that, and if the answer is vague, that tells you something.
Where the operator changes the risk
Two injections can carry the same name and not be the same procedure. Placement decides whether the biologic reaches the pathology, and dose decides whether there is enough of it to matter. Aneesh Garg, DO, CAQ performs every Dynamic PRP+ injection under live ultrasound, and you can read why concentration matters on is PRP worth it or see the full protocol on the PRP therapy page.
Who should wait or be treated differently
These are reasons to postpone or reconsider, and a clinic should be asking about them before you book.
- Active infection anywhere, and particularly at or near the injection site
- A significant bleeding or clotting disorder, or anticoagulation that has not been reviewed
- Active cancer, without oncology input
- A very low platelet count or significant anaemia
- Pregnancy, which should be discussed before any elective injection
Before you book, ask
- Will the injection be placed under live ultrasound?
- What platelet concentration am I getting, and how do you know?
- Who performs the injection, and are they a physician?
The question most clinics cannot answer
Ask what concentration your PRP will be. Many clinics do not measure it, which means they cannot tell you the dose of the only active ingredient in the treatment. If nobody can name the number, nobody is controlling it.
Frequently asked questions
What are the side effects of a PRP injection?
The common side effect is soreness in the treated joint or tendon for a few days, often worse than the pain you started with and typically peaking within the first 48 hours. In the published literature transient post-injection pain is the most frequently reported event, and systematic reviews describe it as self-limiting rather than as a complication. Some people notice mild swelling or bruising at the needle site. Because PRP is autologous, made from a sample of your own blood, allergic reaction and rejection are not part of the risk profile, which is why the list of possible side effects is much shorter than for a foreign injectate.
Is PRP safe?
For an appropriately screened patient it has a favorable safety profile, and the main reason is that the injectate is your own blood rather than a drug. Systematic reviews of intra-articular PRP, including work in hip and knee osteoarthritis, report complication rates comparable to corticosteroid and saline injections, with adverse events that are predominantly minor, transient injection-site reactions. The rare serious risk is infection, which is the risk any injection carries and which sterile technique in a controlled clinical setting is designed to prevent. Safety here depends less on the biologic than on screening, sterility and who performs the procedure.
How long does the soreness last after PRP?
Usually a few days. The pattern most patients describe is a deep ache that builds over the first day or two, peaks around 48 hours, then eases steadily through the rest of the first week. Ice and relative rest are the usual management, along with paracetamol if you need something. The part that matters is the direction of travel: soreness that is easing by day four is the expected course, while pain that is escalating after day three or four is not, and that should prompt a phone call to the clinic rather than waiting to see whether it settles on its own.
Can I take ibuprofen after a PRP injection?
Not unless your physician tells you otherwise, and usually we ask you to avoid it. PRP works by provoking a controlled inflammatory and healing response in the tissue, and non-steroidal anti-inflammatory drugs are specifically designed to suppress that response, so taking them through the treatment window can reasonably be expected to work against the result you are paying for. Paracetamol and ice are the usual alternatives. If you take an anti-inflammatory regularly for another condition, raise it before the injection rather than afterwards, because it changes the plan rather than ruling you out.
What are the signs something has gone wrong after PRP?
Escalating rather than settling pain after the third or fourth day, fever, spreading redness or heat around the site, or any drainage from the injection site. None of those belong to the expected pattern and all of them warrant a same-day telephone call to the clinic rather than a wait-and-see approach. Infection after an injection is genuinely rare, and it is rare because sterile technique and a controlled setting prevent it. What you should not do is assume that worsening pain is just a strong flare, because the difference between a flare and an infection is time-sensitive.
Who should not have PRP?
You should postpone or be assessed differently if you have an active infection, particularly at or near the injection site; a significant bleeding or clotting disorder, or anticoagulation that has not been reviewed; active cancer, without input from your oncologist; a very low platelet count or significant anaemia, because platelets are the active ingredient and if your blood cannot supply them the treatment cannot work properly; or if you are pregnant, which should be discussed before any elective injection. None of these are permanent disqualifications in every case. They are reasons for a physician to look before treating.
Does the PRP concentration change the side effects?
Concentration mostly changes the likelihood of benefit rather than the side effect profile, though a higher dose can mean a more noticeable flare in the first days, which is consistent with a stronger biological response. The more important point is that dose is the variable most patients never ask about. A systematic review and meta-analysis on platelet dose and musculoskeletal outcomes exists precisely because it matters. Dynamic PRP+ is concentrated to 12 to 20 times baseline, over 10 billion platelets, combined with Exosome-Containing Fibrin-Rich Plasma, and a clinic that cannot state its number is not controlling it.
How soon can I go back to training after PRP?
Light daily activity is usually fine immediately, but hard loading of the treated tissue is not, and the timeline depends on the tissue and the problem rather than on a general rule. The principle is that you want the tendon or joint to heal into a controlled progression rather than be provoked at the point when it is most reactive. We give you a specific plan at the time of injection, because a shoulder, a knee and an Achilles do not follow the same schedule. Treat any advice that gives one universal return-to-sport number for all PRP with suspicion.
Ask about PRP with the physician who performs it
Same-week evaluations with Aneesh Garg, DO, CAQ. He takes the history, examines you, images the problem where it helps, and performs every Dynamic PRP+ injection himself under live ultrasound. If PRP is not the right tool for your problem, he will say so.
Book an Evaluation
1790 30th Street Suite 270 · Boulder, CO 80301 · 303-997-1733