Platelet-rich plasma is made from your own blood. A vial is drawn, spun in a centrifuge to concentrate the platelets, and the resulting plasma is injected back into a joint, tendon, scalp, or facial skin. Because the material is autologous — yours — the two biggest risks of any injected biologic, allergic reaction and disease transmission, are largely off the table.

That does not make PRP risk-free. It involves needles, sometimes deep ones, and it reliably produces a few days of discomfort that catches people off guard if nobody warned them.

This guide is information, not medical advice. Your own history, medications, and the specific site being treated matter more than any general article.

First, what "not FDA-approved" means for safety

The centrifuges and kits used to prepare PRP are cleared by the FDA as devices — cleared to spin blood and produce a platelet concentrate. That clearance is not an approval of PRP as a treatment for knee arthritis, tennis elbow, hair loss, or anything else. Nearly every clinical use of PRP in the United States is an off-label or unapproved application, delivered under the practice of medicine.

Practically, that means no regulator has reviewed a safety dossier for PRP-for-your-condition the way one would for a new drug. There is no mandatory adverse-event reporting system capturing what happens in aesthetic and orthopedic offices. The safety record looks good in published trials, but published trials are small, often short, and — as a Cochrane review of platelet-rich therapies for musculoskeletal soft tissue injuries noted — inconsistent in how they report harms. That review found no signal of increased harm from PRP, but also judged the overall quality of evidence low. "No signal in low-quality data" is reassuring, not conclusive.

The FDA has also been explicit that regenerative medicine products marketed outside its approval pathways carry real risk, and has issued repeated warnings about unapproved stem cell and related offerings. PRP sits at the lower-risk end of that landscape, but it is still in it.

What's normal after PRP

For most people, in most sites, the expected course looks like this:

  • Pain and soreness at the injection site, usually peaking in the first 24 to 72 hours.
  • Swelling and stiffness, especially after an intra-articular (inside the joint) injection.
  • Bruising, from both the blood draw and the injection.
  • A headache or scalp tightness after scalp PRP, lasting a day or two.
  • Facial puffiness and pinpoint bleeding after PRP combined with microneedling, typically settling within 48 hours.
  • Feeling lightheaded during the draw or injection. Vasovagal reactions are common with any needle procedure and are not a sign something went wrong.

The American Academy of Orthopaedic Surgeons' patient materials on PRP describe post-injection pain as an expected part of the procedure rather than a complication.

The post-injection flare

This is the one that surprises people. PRP works — to whatever extent it works — by provoking an inflammatory and healing response. A flare of increased pain lasting several days to about two weeks is common, particularly in joints and tendons. Some patients describe the first week as worse than their baseline.

A flare is not evidence of a failed treatment, and it is not evidence of a successful one either. It is simply the expected biology. Most clinicians advise avoiding anti-inflammatory medications such as ibuprofen and naproxen for a window before and after the injection, on the theory that blunting inflammation may blunt the effect. That reasoning is mechanistic rather than proven by outcome trials, but it is the common protocol — which means acetaminophen and ice are often your only tools during the worst of it. Ask what you're allowed to take before you leave the office.

What's not normal

These are uncommon, but they are the reasons to pick up the phone.

Infection. Any injection breaches the skin. Infection after a joint injection of any type is rare, but septic arthritis is a surgical emergency. Warning signs: pain that worsens after day three or four instead of improving, redness spreading outward from the site, warmth, drainage or pus, or fever and chills.

Nerve or vessel injury. Rare, and more plausible with deep injections near nerves. Persistent numbness, tingling, shooting pain, or new weakness in a limb needs evaluation.

Bleeding or a large hematoma. More likely if you are on anticoagulants or antiplatelet drugs, or have a bleeding disorder. A rapidly expanding, hard, painful swelling is not a routine bruise.

Tendon rupture. Reported rarely after injection into or near a tendon. Sudden loss of function, a pop, or inability to bear weight is urgent.

Reactions to additives. Some PRP preparation systems use bovine thrombin as an activator. Repeated exposure has been linked in the older literature to coagulation abnormalities. It is reasonable to ask whether anything other than your own blood and an anticoagulant like citrate is going into the syringe.

Anything involving vision. If you have facial injections and develop visual changes, blanching or mottling of the skin, or severe disproportionate pain, seek care immediately. This risk is associated primarily with fillers rather than PRP, but PRP is frequently sold alongside fillers in the same appointment, and the distinction matters when something goes wrong.

Who probably shouldn't get PRP

Contraindication lists for PRP are mostly consensus and physiology, not the output of trials — there is no randomized study of PRP in people with active cancer, and there never will be. Treat the list as prudence rather than proof.

Generally considered absolute:

  • Active infection at the injection site, or systemic infection.
  • Significantly low platelet count or a known platelet function disorder — the product depends on your platelets being both numerous and functional.
  • Severe anemia or hemodynamic instability.

Generally considered relative — discuss, don't assume:

  • Anticoagulant or antiplatelet therapy. Warfarin, DOACs, clopidogrel, and daily aspirin increase bruising and bleeding risk, and antiplatelet drugs may reduce the activity of the product itself. Do not stop a prescribed blood thinner to get a cosmetic or elective injection without the prescribing physician's sign-off. The clot you're preventing is a worse problem than the one you're treating.
  • Active or recent malignancy. PRP delivers a concentrated dose of growth factors. Whether that could stimulate tumor tissue is unresolved; most practitioners decline to treat during active cancer, especially hematologic cancers or disease involving bone.
  • Pregnancy and breastfeeding. Not studied. Elective procedures are typically deferred.
  • Autoimmune or inflammatory conditions, and immunosuppressive therapy.
  • Recent corticosteroid injection at the same site, or recent systemic steroids.
  • Active smoking and poorly controlled diabetes, both of which impair healing generally.

One more worth saying plainly: if the cost of a complication would be ruinous to you, factor it in. PRP is almost never covered by insurance — sessions commonly run from a few hundred dollars to a couple of thousand depending on the site and the number of injections — and the imaging, antibiotics, or specialist visit that follows a rare complication may not be covered as a complication of an elective procedure either.

When to call

Call the treating clinic if, after 72 hours, pain is escalating rather than easing; if you see spreading redness, warmth, or drainage; if you develop a fever above 100.4°F; if you have new numbness or weakness; or if a bruise is enlarging rather than fading.

Go to an emergency department for a hot, swollen joint you cannot move, a fever with rigors, sudden loss of limb function, or any visual change after facial injection.

Before you consent, ask who answers the phone after hours and on weekends. A clinic that cannot give you a straight answer to that question is telling you something about how it handles the small number of cases that go sideways.