Prolotherapy is an injection treatment that provokes a controlled healing response in tissue that has stopped repairing itself — typically a tendon, ligament or joint capsule with long-standing damage.
The name is short for proliferation therapy, and the mechanism is in the name: the aim is to restart proliferation where it has stalled.
What is actually in the injection
The classic preparation is hyperosmolar dextrose — a concentrated sugar solution, usually with a local anaesthetic to make the injection tolerable. Nothing biological, nothing proprietary.
That is the whole of it, and the plainness of the ingredient is often what makes people suspicious. The activity is not in the dextrose as a substance; it is in what a hyperosmolar solution does to the tissue it is placed in.
Two related treatments use different contents:
- Platelet-rich plasma substitutes the patient's own concentrated platelets for dextrose. Robert Stall, MD, who teaches the subject for Empire, is explicit that “PRP is a subcategory of prolotherapy” — same healing sequence, different initiator.
- Perineural injection therapy uses a much weaker buffered 5% dextrose placed around nerves rather than into connective tissue, and works by an entirely different mechanism.
How it works
The sequence is defined, and each stage explains something patients notice.
Stage one: inflammation, three to seven days. The injection deliberately creates inflammation in pathological tissue, along with some local bleeding. That triggers cytokine cascades and draws inflammatory cells to the area, raising cellular activity and growth factor concentration.
This is the stage that explains post-injection soreness. Stall notes that not every patient experiences a pain exacerbation, but if one occurs, this is when.
Stage two: proliferation, from about 72 hours to six weeks. Myofibroblasts, fibroblasts and endothelial cells arrive and lay down new type I and type III collagen. Patients start to notice improvement in pain and function during this window.
Stage three: remodelling, from two weeks to as long as two years. Collagen cross-links mature and reorganise into the fibrillar pattern of healthy tendon and ligament, replacing what Stall describes as “the disorganised, fragile structure of prior tendinosis or tears.”
That third stage is the actual objective — in his words, “the eventual re-establishment of more physiologically normal tissue represents the fundamental and ultimate goal of prolotherapy, including PRP.”
The instruction that protects the result
There is one piece of aftercare advice that matters more than the rest, and it is counterintuitive.
During proliferation the new collagen is, as Stall puts it, still “immature and disorganised.” The tissue is being rebuilt but is not yet strong. Patients are therefore at increased risk of injury at precisely the moment they start feeling better.
Feeling improved at three weeks and returning to full loading is how a promising result gets undone. The improvement is real; the tissue supporting it is not yet mature.
What it is used for
Prolotherapy is used for chronic tendon and ligament problems that have not responded to time, rest and rehabilitation — tendinopathy, ligament laxity, and joint pain with a soft-tissue component.
The strongest published results in the wider category sit in tendon. For lateral epicondylitis a single PRP injection produced significantly greater improvement than corticosteroid in one study, maintained at two-year follow-up. Achilles tendon repair augmented with PRP improved recovered range of motion and return to sport compared with repair alone.
What it does not do is regrow cartilage or reverse established arthritis.
How many injections
Honestly, nobody knows the optimum. Stall states it directly: “the ideal injection regimen remains undefined and there are contradictions within the published literature.”
The known biology sets sensible bounds. Healing does not begin until several weeks after injection, so common practice is not to inject more often than monthly. Because remodelling continues for a year or more, there is no contraindication to injecting less often than that.
Treat a fixed package of three, sold before the first result is known, as a commercial structure rather than a clinical one.
Does it hurt, and what happens afterwards
The injection itself is uncomfortable — a hyperosmolar solution placed into tendon or ligament is not a gentle sensation, which is why local anaesthetic is usually included.
Afterwards, expect soreness for a few days as the inflammatory phase runs. Anti-inflammatories are generally avoided in this window, since the inflammation is the intended mechanism rather than a side effect.
Improvement typically begins somewhere in the proliferation phase, several weeks out — not in the first few days.
Is it legitimate?
It has a defined mechanism, a described healing sequence and published benefit in specific indications, particularly tendon. It is also surrounded by claims the evidence does not support, and the trial literature genuinely does contradict itself for reasons explored in is prolotherapy a hoax.
The reasonable position is that it is a treatment with moderate evidence in selected soft-tissue conditions, measured in months rather than days, and worth considering when conservative management has failed and the alternative is surgery or continued pain.
Learn blocks with your hands, not from a page
Empire’s Pain Management Training (THE Pain Show) is accredited for 25.25 AMA PRA Category 1 Credits™, jointly provided by AKH, Inc, and Empire Medical Training. For narrower peripheral work, Joint, Extremity and Non-Spinal Injection Training carries 6.75 credits for the complete in-person hybrid program, and Advanced Musculoskeletal Ultrasound Guided Injections builds the guidance skills above.
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