PRP Injections

Platelet-rich plasma is conceptually irresistible: draw the patient's blood, centrifuge it to concentrate platelets (the body's wound-response packets, dense with growth factors), and inject the concentrate where healing is wanted — tendons, joints, scalps, faces, and increasingly anywhere with a paying customer. The appeal stack is complete: autologous (your own tissue — no rejection, minimal regulation), mechanistically fluent (growth factors! regeneration!), procedurally satisfying (a real needle, a real machine, your visible yellow plasma), and priced like it matters ($500-2,500 per course, out of pocket almost everywhere). What the concept skipped was standardisation — “PRP” names a family of wildly different products (platelet concentrations varying tenfold, leukocyte-rich versus leukocyte-poor, activated or not, single or serial injections) prepared on dozens of systems — and outcome proof, which two decades of trials have now supplied in a pattern this hub scores: the biggest, best trials of the flagship uses came back null, the niches hold modest signals, and the market never adjusted.

PRP's home turf — musculoskeletal medicine — has delivered the field's most decisive answers. Knee osteoarthritis: after years of mixed small trials feeding meta-analytic optimism, the landmark RESTORE randomised trial (JAMA 2021: PRP versus saline, properly blinded) found no significant benefit for pain or cartilage volume at 12 months — the highest-quality answer the question has received; Achilles tendinopathy: the parallel large UK trial (JAMA 2021) — no benefit over sham injection; the broader tendon file (tennis elbow, patellar, rotator cuff) remains genuinely mixed, with tennis elbow holding the most persistent positive signals amid preparation chaos and blinding problems. Professional verdicts track the evidence: major orthopaedic and rheumatology guidance ranges from “cannot recommend” to “uncertain — not routine”, insurers classify it investigational, and the honest orthopaedic summary is that PRP has had its big-trial moment for the bestseller indications and lost — while remaining biologically interesting enough that specific preparations for specific tendons stay a legitimate research line. The clinics' menus, meanwhile, still lead with knees.

Beyond orthopaedics, the indication sprawl sorts into tiers. Pattern hair loss: the expansion market's best corner — multiple small randomised trials show modest density improvements, meta-analyses lean positive, protocols vary maddeningly, and dermatology treats it as a reasonable adjunct for selected patients who understand the maintenance requirement and the evidence tier below finasteride/minoxidil. The “vampire facial” and aesthetics: microneedling-plus-PRP for skin rejuvenation runs on small split-face studies and celebrity history — cosmetic-tier evidence for cosmetic-tier claims, which would be unremarkable except for the safety file: an unlicensed New Mexico spa's unsterile practice produced confirmed HIV transmissions among vampire-facial clients — the case that put “autologous” marketing's hidden dependency (bloodborne-pathogen discipline) on the record. The frontier absurdities: PRP injected for sexual “rejuvenation” (trademarked O-Shot/P-Shot economies), ovarian “rejuvenation” for fertility, and joint-adjacent everything — evidence-free trademark medicine at four figures, marking where the field's serious researchers stop and its franchise economy begins.

PRP's literature problem is structural and worth understanding because it powers both the sales pitch and its rebuttal. No two PRPs are alike: platelet dose, leukocyte content (leukocyte-rich preparations provoke more inflammation — plausibly better for some tendons, worse in joints), activation method, volume, injection count and imaging guidance all vary — so every null trial can be answered with “wrong preparation” and every positive one challenged the same way, a permanent epistemic escape hatch this collection recognises from other unstandardised therapies. The blinding problem compounds it: patients feel their blood drawn and centrifuged, saline controls behave differently on injection, and subjective pain outcomes do the rest. The honest reading of the muddle cuts both ways: the field genuinely might contain effective preparation-indication pairs not yet isolated (the research case for continuing well-designed trials), and the market's current practice — selling unstandardised product for indications whose best trials failed — cannot borrow that possibility as proof. “More research needed” is a status, not a licence.

Pricing the decision honestly, by indication. Knee OA: PRP courses cost $1,500-3,000 against the RESTORE null — while the interventions with actual evidence (structured exercise therapy, weight loss where relevant, staged analgesia, and timely surgical evaluation when criteria are met) are cheaper and insured; buying PRP first buys delay. Tendinopathy: eccentric loading and progressive rehabilitation own the evidence base; PRP as an adjunct for refractory tennis elbow is a defensible conversation with a sports-medicine physician — as a first-line clinic upsell it is queue-jumping the proven for the profitable. Hair: PRP's modest trial support sits below finasteride and minoxidil in evidence and above them in price and needles — rational as an adjunct or alternative for patients who've exhausted or declined first-line, irrational as an opener. Aesthetics and the rejuvenation trademarks: discretionary spending on cosmetic-tier evidence — with sterility diligence non-negotiable (the New Mexico file) and the four-figure intimate-injection economy declined on both evidence and dignity grounds. Across all of it, the universal questions: which preparation, matching which trial, for which indication, against which cheaper proven alternative — four answers most clinics have never been asked for.

For knee osteoarthritis: the best trial says no — spend on exercise therapy, weight management and proper staged care instead, and treat PRP-first clinics as a screening test you can fail on their behalf. For tendinopathy: rehabilitation first, always; PRP only as a specialist-guided adjunct conversation for refractory cases (tennis elbow the least unreasonable), with expectations set by mixed evidence. For hair loss: reasonable third-tier option — after or alongside the first-line drugs, from providers publishing their protocol, with maintenance sessions priced into the decision. For anything cosmetic or “rejuvenating”: cosmetic-tier evidence, medical-tier sterility required — verify licensure and single-use disposables without embarrassment, because the HIV cluster came from exactly that corner cut. Never accept PRP for fertility, sexual function or trademark-branded anything without asking for the randomised trial by name — there isn't one, and the silence is the answer. And the field-level frame to keep: PRP is not fraud — it is a plausible, unstandardised, mostly-unproven family of products whose sellers charge proven-therapy prices; pay for evidence, not centrifugation.