If you've been researching options for a knee that aches on stairs, a shoulder that never fully recovered, or back pain that flares every time you overdo it, you've probably come across prolotherapy — and probably also come across two kinds of websites: ones that call it a miracle, and ones that call it snake oil.
Neither is accurate. Prolotherapy is one of the older regenerative injection techniques — it has been used clinically since the 1930s and has a robust amount of clinical trials. This post walks through what that research shows, where it's strong, where it's thin, and how we think about it clinically at the Upper Room Clinic.
First, at a glance: what prolotherapy is
Prolotherapy is the injection of a concentrated dextrose (sugar) solution, usually with a local anaesthetic, into a painful joint, ligament or tendon. The dextrose acts as a mild, deliberate irritant. That sounds counterproductive until you remember how tissue heals: injury → local inflammation → repair. Chronic pain often means that cycle stalled and the tissue settled into a weakened state without finishing the repair phase. Prolotherapy is designed to restart it.
Prolozone® is a variation that adds medical ozone gas to the injection, with the goal of improving oxygen delivery and stimulating repair in tissues with poor blood supply — which describes most ligaments and tendons.
The strongest evidence: knee osteoarthritis
Knee arthritis is where prolotherapy has been studied most rigorously.
The landmark study is a randomized controlled trial published in the Annals of Family Medicine (2013) by Dr. David Rabago's group at the University of Wisconsin. Ninety adults with painful knee osteoarthritis were randomized to dextrose prolotherapy, saline injections, or at-home exercise. The prolotherapy group improved significantly more on the WOMAC score — the standard measure of knee pain, stiffness and function — and, importantly, the improvement was still there at one year.
That result hasn't stood alone. A 2020 randomized trial from Hong Kong, also in the Annals of Family Medicine found intra-articular dextrose injections effective for knee osteoarthritis, and a 2020 randomized controlled study reported meaningful improvements in pain and function versus controls. A systematic review and meta-analysis in Scientific Reports pooled the available trials and concluded that hypertonic dextrose injections outperformed comparators for knee osteoarthritis pain and function. More recent work continues to refine the technique — for example, a double-blind randomized trial comparing injection sites around the knee.
Tendon and ligament pain: promising, more mixed
For chronic tendon problems — tennis elbow, plantar fasciosis, Achilles and rotator cuff tendinopathy — randomized trials and systematic reviews suggest prolotherapy can reduce pain and improve function, particularly in stubborn cases that haven't responded to rest and physiotherapy. The trials here are smaller and use more varied techniques than the knee studies. Clinically, tendinopathy is one of the areas where we most often see prolotherapy earn its keep, precisely because the alternatives (more rest, more anti-inflammatories) so often haven't worked by the time patients reach us.
What about Prolozone specifically?
Most published trials studied dextrose-only prolotherapy. Medical ozone has its own body of research — including randomized trials of ozone injections for knee osteoarthritis — but studies of the combined prolozone technique are earlier-stage: case series, smaller cohorts, and mechanistic work rather than large blinded trials. The dextrose component carries the strongest trial evidence; ozone adds a plausible, oxygen-driven repair mechanism with a growing but younger literature.
The honest limitations
There are a few limitations to consider when examining the primary literature around prolotherapy:
- The trials are small. Most enrol 40–100 people. The results are consistent, but this isn't the size of the evidence base behind, say, blood pressure medication.
- Blinding is hard. A dextrose injection feels different from saline, and "did my pain improve?" is subjective. Researchers control for this as best they can.
- It doesn't regrow cartilage. In knee arthritis, prolotherapy improves pain and function; it does not reverse bone-on-bone joint loss. End-stage arthritis usually needs a surgical conversation, and we'll tell you that at consultation.
- Response varies. Most patients need 3–6 sessions, and a minority don't respond meaningfully. Anyone promising guaranteed results is overpromising.
The final verdict: does it work?
For the right patient, the research says yes, with realistic expectations: knee osteoarthritis has randomized-trial support with benefits lasting a year or more; chronic tendon and ligament pain has promising smaller-trial support; and the safety profile across all of it is excellent when performed by a trained physician.
The "right patient" part matters. Prolotherapy works best when pain comes from weakened connective tissue — not from active infection, inflammatory arthritis flares, or joints that have structurally failed. That's why every course at the Upper Room Clinic starts with a physician assessment, performed by Dr. Biljana Kostovic or another physician, of whether your problem is actually one the research supports treating.
Prolotherapy at the Upper Room Clinic
At our Toronto and Oakville clinics, prolotherapy and Prolozone® injections are performed by physicians, led by Dr. Biljana Kostovic, MD, with over 30 years in integrative and chronic pain medicine. Treatment costs $270–$350 per site with most plans running 3–6 sessions — full details on our Prolotherapy & Prolozone page and price list. Prolotherapy isn't OHIP-covered, though many extended health plans reimburse physician-performed injections, and eligible chronic pain patients can ask about our OHIP-covered interventional pain program.
If you're weighing prolotherapy against PRP or cortisone, we've written a detailed comparison here — or book a discovery call and we'll assess which approach the evidence supports for your specific joint.
