Shock wave therapy is considered safe for most people. Across a systematic review of 39 studies covering nearly 2,500 patients and over 6,400 treatment sessions, the side effects reported were mild and temporary: skin reddening, short-lived pain, and minor swelling. Serious complications are exceptionally rare, and the therapy is FDA-cleared as a noninvasive treatment option. That said, certain health conditions and medications can change the risk picture significantly.
How Shock Wave Therapy Works
Shock waves are rapid pressure pulses that travel through tissue in nanoseconds. When directed at an injured area, they transfer energy into cells in three phases. First, the physical impact creates pressure changes that stimulate cells mechanically. Then, affected cells release signaling molecules that kick-start repair processes. Finally, a biological cascade follows: new blood vessels form, inflammation decreases, and bone or soft tissue begins to heal.
This is why the therapy is used for conditions like plantar fasciitis, tendon injuries, and certain bone-healing problems. The FDA has cleared specific devices for treating chronic plantar fasciitis in adults who haven’t improved after six months of conservative treatment. Clinicians also use it off-label for a growing list of musculoskeletal conditions, including knee osteoarthritis and calcific shoulder tendinitis.
Common Side Effects
The most frequently reported side effects are pain during the session and temporary redness at the treatment site. In the systematic review of plantar fasciitis patients, 225 out of roughly 2,500 reported pain during treatment, and 247 experienced transient skin reddening afterward. Other reported effects included localized swelling, bruising, small red spots under the skin (petechiae), numbness or tingling, and occasional headache. All of these resolved on their own.
Some patients describe minor discomfort like skin reddening or swelling that fades within hours to a couple of days. No patients in multiple studies discontinued treatment because of side effects. Higher-intensity treatments tend to cause more discomfort during the session and sometimes require local anesthesia, though anesthesia may reduce the therapy’s effectiveness.
Rare but Serious Complications
Serious adverse events are exceptionally uncommon. The short list, documented across years of clinical use, includes Achilles tendon rupture, bone death in the upper arm (after focused high-energy treatment), and stress-type fractures in the heel bone. These have been reported in isolated cases, not as a pattern, and are associated specifically with focused, high-energy applications rather than the lower-energy radial type commonly used in outpatient clinics.
One important safety boundary involves the lungs. Shock waves can cause tears, bleeding, or a collapsed lung if the treatment area overlaps with lung tissue. Practitioners are trained to ensure the lungs stay outside the path of the shock waves, making this a preventable risk rather than an inherent one.
Focused vs. Radial: Safety Differences
There are two main types of shock wave therapy. Focused shock waves concentrate energy at a specific depth and deliver higher intensity. Radial pressure waves spread outward from the skin surface and deliver lower energy over a broader area. Most of the rare serious complications, like bone injury, have been linked to focused, high-energy treatments.
In a randomized controlled study comparing focused and radial shock wave therapy for knee osteoarthritis, neither group reported any adverse events. Both types are generally well tolerated, but radial therapy carries a milder side-effect profile because of its lower energy output. Your provider will choose the type based on the condition being treated and the depth of the target tissue.
Who Should Avoid It
The International Society for Medical Shockwave Treatment maintains a list of contraindications, divided into absolute and relative categories.
You should not receive any form of shock wave therapy if you:
- Are pregnant, since shock waves must never be directed near a fetus or embryo
- Have an active infection like osteomyelitis at the treatment site
- Have a malignant tumor in or near the treatment area (for focused shock waves)
High-energy treatments specifically should be avoided if the treatment zone involves brain tissue, the spinal cord, lung tissue, or a growth plate in children and adolescents. Severe clotting disorders are also a contraindication for high-energy applications.
Blood Thinners and Medications
If you take blood-thinning medications like warfarin or antiplatelet drugs like aspirin, the safety calculation becomes more nuanced. One of the known side effects of shock wave therapy is bruising and small blood vessel rupture, which clotting medications can worsen.
Full anticoagulation is generally considered a contraindication. For patients on antiplatelet agents, the approach depends on your cardiovascular risk level. People at low risk for blood clots may be able to temporarily stop their medication for up to seven days around the procedure, but only after consulting with the prescribing cardiologist. People at intermediate or high cardiovascular risk are typically advised to postpone elective treatment or explore alternatives, because the risk of a clotting event from stopping medication outweighs the benefit of the therapy.
Current use of anti-inflammatory drugs (like ibuprofen) and recent corticosteroid injections are also flagged as important considerations. These don’t necessarily rule out treatment, but your provider should know about them before proceeding.
Pacemakers and Implanted Devices
Having a cardiac pacemaker or other implantable device doesn’t automatically disqualify you, but it does require precautions. Studies on lithotripsy (a related shock wave procedure) in patients with pacemakers have been conducted with continuous heart monitoring during treatment, immediate device checks afterward, and protocols to stop the session if any irregular heart rhythms develop. If you have an implanted device, expect your provider to take similar precautions or consult with your cardiologist before scheduling treatment.
What Recovery Looks Like
Recovery from a shock wave therapy session is minimal for most people. There’s no surgical wound, no sedation to wear off, and no extended downtime. The most common post-treatment experience is mild soreness or redness at the site, similar to what you might feel after deep tissue massage. This typically resolves within a day or two.
Most treatment protocols involve three to five sessions spaced a week apart, and many patients continue their normal daily activities between sessions. Your provider may suggest avoiding high-impact exercise on the treated area for 24 to 48 hours after each session, particularly with higher-energy treatments, but prolonged rest is not typically required.
Long-Term Safety Profile
Across the available research, no pattern of chronic or delayed complications has emerged from shock wave therapy. The systematic review of nearly 2,500 patients found only transient side effects, with no reports of lasting tissue damage. A randomized trial in knee osteoarthritis patients recorded zero adverse events across both treatment groups. The therapy has been in clinical use since the 1980s for kidney stones and since the early 2000s for musculoskeletal conditions, providing a reasonably long track record.
The overall picture is that shock wave therapy carries a low risk profile when applied by trained practitioners who screen for contraindications. The side effects that do occur are predictable, mild, and self-resolving. The rare serious events are tied to high-energy focused applications and specific anatomical vulnerabilities, making them largely preventable with proper technique and patient selection.