If you have ever experienced swelling, soreness, or pain after an injury, you may have heard that laser therapy can reduce inflammation. But what does the research actually say?
Therapeutic laser therapy, also called photobiomodulation therapy (PBM), has been studied for its potential effects on pain, inflammation, tissue recovery, and function.
Research suggests that photobiomodulation can influence biological pathways involved in inflammation. However, it is important to understand that laser therapy does not simply "turn inflammation off." The effects depend on the type of injury or condition, treatment parameters, and how laser therapy is incorporated into a larger rehabilitation program.
For patients, the most accurate takeaway is:
Physical therapy laser treatment may help regulate inflammatory processes and reduce pain associated with certain musculoskeletal conditions, but it should be viewed as an adjunct to comprehensive rehabilitation rather than a stand-alone treatment.
What Is Laser Therapy?
Therapeutic laser therapy uses specific wavelengths of light to deliver energy to targeted tissues.
The broader treatment approach is known as photobiomodulation.
Unlike surgical lasers that cut or remove tissue, therapeutic lasers are designed to interact with tissue at specific wavelengths and energy levels without intentionally damaging it.
Depending on the device, photobiomodulation may use red or near-infrared wavelengths.
The biological response can depend on several factors, including:
- Wavelength
- Power
- Energy delivered
- Treatment area
- Treatment duration
- Frequency of treatment
- Tissue being treated
- Patient characteristics
Because of these variables, not every laser treatment should be expected to produce the same results.
What Is Inflammation?
Inflammation is part of the body's natural response to injury, infection, or tissue stress.
It involves a complex interaction between immune cells, blood vessels, signaling molecules, and surrounding tissues.
Inflammation is not automatically a bad thing.
In the appropriate situation, inflammation can be an important part of the body's normal healing response.
The problem occurs when inflammatory processes become excessive, prolonged, or associated with persistent symptoms.
This is why the goal of physical therapy is generally not to eliminate inflammation completely.
Instead, treatment focuses on helping the body manage symptoms while restoring movement, strength, and function.
How Could Laser Therapy Affect Inflammation?
Researchers have investigated several possible mechanisms through which photobiomodulation may influence inflammatory processes.
Laboratory and clinical research suggests that PBM may affect:
- Inflammatory signaling molecules
- Oxidative stress
- Cellular metabolism
- Immune-cell activity
- Blood flow
- Pain signaling
- Tissue repair processes
A systematic review examining PBM for pain and inflammation found that some randomized controlled trials reported improvements in inflammatory outcomes, while others did not. The authors emphasized that differences in treatment protocols and study quality make it difficult to draw a universal conclusion about inflammation.
This is an important distinction.
Laser therapy may influence inflammation, but the research does not support saying that laser therapy universally eliminates inflammation.
Does Laser Therapy Actually Reduce Inflammation?
The short answer is:
It may, but the evidence is condition-specific.
Some research demonstrates changes in inflammatory markers or inflammatory responses following photobiomodulation. Other studies have not found significant changes.
A 2025 umbrella review of randomized clinical trial meta-analyses evaluated 204 RCTs involving more than 9,000 participants across numerous health outcomes. The review found evidence of potential benefits from photobiomodulation across several conditions, but the certainty of evidence varied substantially depending on the outcome.
This means laser therapy should not be marketed as a universal anti-inflammatory treatment.
Instead, it may be considered an evidence-informed modality that can be appropriate for certain patients and conditions.
Can Laser Therapy Reduce Swelling?
Swelling is another area where photobiomodulation has been investigated.
Inflammation and swelling are related, but they are not exactly the same thing.
Laser therapy may influence some of the biological processes associated with tissue inflammation and fluid accumulation. However, whether a patient experiences a meaningful reduction in swelling depends on the cause of the swelling and the overall treatment approach.
For example, swelling after surgery may require a combination of:
- Appropriate movement
- Exercise
- Elevation
- Compression when appropriate
- Manual techniques
- Activity modification
- Medical management
- Other physical therapy interventions
Laser therapy may be considered as one component of this plan.
Can Laser Therapy Help With Pain Caused by Inflammation?
This is where the clinical research is particularly relevant.
Inflammatory processes can contribute to pain by increasing sensitivity in surrounding tissues and affecting how the nervous system responds to mechanical and chemical signals.
Photobiomodulation has demonstrated potential pain-relieving effects across several musculoskeletal conditions.
For example, a systematic review and meta-analysis of 17 studies involving 944 patients with upper trapezius myofascial pain found that PBM reduced pain and increased pressure pain thresholds. The researchers found particularly positive effects when PBM was combined with exercise, although the overall quality of evidence ranged from low to moderate.
This supports an important clinical concept:
Reducing pain can help a patient participate more comfortably in active rehabilitation.
What About Knee Osteoarthritis?
Knee osteoarthritis is one of the conditions where photobiomodulation has been studied extensively.
A 2024 systematic review and meta-analysis in Physical Therapy included 10 randomized controlled trials involving 542 participants.
The researchers found that PBM significantly reduced pain at rest compared with placebo.
However, the researchers rated the certainty of evidence as very low because the included studies had unclear or high risk of bias.
Their conclusion was that photobiomodulation may complement other recommended treatments but should not be considered an isolated treatment for knee osteoarthritis.
This is a good example of what evidence-based laser therapy should look like.
Rather than replacing strengthening or exercise, laser therapy may be used to help manage symptoms while the patient works toward improved strength and function.
What About Muscle Inflammation?
Laser therapy has also been investigated for muscle-related pain and inflammatory responses.
Research suggests that photobiomodulation can influence cellular processes associated with oxidative stress and inflammatory signaling.
However, much of the evidence regarding specific inflammatory mechanisms comes from laboratory research or studies involving specific conditions.
Therefore, it would be inaccurate to say:
"Laser therapy removes muscle inflammation."
A more evidence-based statement is:
"Photobiomodulation may influence biological pathways involved in inflammation and may help reduce pain associated with certain musculoskeletal conditions."
Can Laser Therapy Help After Exercise or a Sports Injury?
Athletes sometimes use photobiomodulation as part of recovery from training or injury.
Research has investigated PBM for:
- Muscle soreness
- Musculoskeletal injuries
- Tendon problems
- Joint pain
- Sports-related pain
- Recovery following exercise
A 2024 systematic review and meta-analysis examining injured athletes found that photobiomodulation may reduce musculoskeletal pain, although the evidence regarding faster return to play was less conclusive.
For an athlete, reducing pain is only one part of recovery.
A complete return-to-sport program may also require:
- Strength testing
- Range-of-motion assessment
- Balance
- Power
- Running progression
- Agility
- Deceleration
- Sport-specific drills
- Load management
Laser therapy cannot replace these components.
Can Class IV Laser Therapy Reduce Inflammation?
Class IV laser therapy refers to higher-powered therapeutic laser systems.
These systems can deliver therapeutic energy at parameters that differ from lower-powered laser devices.
Research on high-intensity laser therapy has reported potential benefits for musculoskeletal pain, and anti-inflammatory mechanisms have been proposed as one possible contributor.
However, it is important not to assume that a higher-powered laser automatically produces a greater anti-inflammatory effect.
The response to photobiomodulation depends on the complete treatment dose, including:
- Wavelength
- Power
- Energy density
- Treatment area
- Treatment duration
- Frequency
More power does not automatically mean better results.
Does Laser Therapy Replace Ice or Other Treatments for Inflammation?
Not necessarily.
Physical therapists have multiple tools available for managing pain and inflammation, and the appropriate treatment depends on the patient's condition.
Depending on the situation, a rehabilitation program may include:
- Therapeutic exercise
- Manual therapy
- Compression
- Mobility work
- Strengthening
- Activity modification
- Education
- Laser therapy
- Other recovery modalities
Laser therapy should be selected based on the patient's individual presentation rather than used simply because inflammation is present.
Does Laser Therapy Speed Up Healing?
This is one of the most common questions patients have.
Photobiomodulation has demonstrated biological effects that may be relevant to tissue recovery, including effects on cellular activity and inflammatory signaling.
However, biological effects do not automatically translate into faster healing for every injury.
Clinical outcomes depend on many factors.
For example, recovering from a tendon injury may require carefully progressed loading over time. Recovering after surgery may require a structured progression of mobility, strength, and functional activity.
Laser therapy may be one tool within that process.
It should not be considered a shortcut around appropriate rehabilitation.
Can Laser Therapy Reduce Inflammation Without Exercise?
Laser therapy can be administered without exercise, but that does not mean exercise is unnecessary.
For most musculoskeletal conditions, active rehabilitation remains an important part of physical therapy.
Consider a patient with knee pain.
Laser therapy may help decrease pain enough for that patient to tolerate strengthening exercises.
The overall progression may look like:
Laser therapy → symptom management → exercise → strengthening → functional movement → return to activity
The goal is not simply to decrease inflammation.
The goal is to help the patient restore function and return to the activities they enjoy.
What Does Laser Therapy Feel Like?
Most patients tolerate therapeutic laser well.
Depending on the device and treatment settings, patients may experience:
- Mild warmth
- Gentle pressure
- Little or no sensation
Laser therapy does not need to hurt to be effective.
Your physical therapist will determine the appropriate treatment parameters based on your condition and treatment goals.
Is Laser Therapy Safe?
Therapeutic laser is generally considered a non-invasive treatment when appropriately administered.
However, laser devices require appropriate safety precautions, particularly around the eyes.
Your physical therapist should also determine whether laser therapy is appropriate based on your medical history, diagnosis, medications, and treatment area.
If you have questions about whether laser therapy is appropriate for you, discuss them with your healthcare provider or physical therapist.
What Does the Research Really Say?
The current evidence supports a potential role for photobiomodulation in managing pain and influencing inflammatory processes, but the strength of evidence varies considerably.
Research has found:
Potential benefits
- Pain reduction in certain musculoskeletal conditions
- Changes in some inflammatory pathways
- Potential improvements in function
- Possible benefits when combined with exercise
Important limitations
- Different wavelengths and treatment parameters are used between studies
- Study quality varies
- Results are not consistent across every condition
- Some outcomes have very low certainty of evidence
- Evidence for reducing specific inflammatory markers is less consistent than evidence for pain reduction
For example, a systematic review focused specifically on PBM and inflammation found that only some of the included randomized trials demonstrated significant improvements in inflammatory outcomes.
This is why evidence-based clinicians should avoid promising that laser therapy will simply "get rid of inflammation."
The Bottom Line
Can physical therapy laser treatment reduce inflammation?
It may influence inflammatory processes and can help reduce pain in certain musculoskeletal conditions, but the evidence does not support describing laser therapy as a universal anti-inflammatory treatment.
The strongest clinical evidence currently supports considering photobiomodulation as an adjunctive treatment rather than a replacement for active rehabilitation.
At Core Performance Physical Therapy, therapeutic laser can be incorporated into an individualized treatment plan when appropriate. It may be combined with therapeutic exercise, strengthening, mobility work, manual therapy, and other evidence-based interventions.
The goal is not simply to "turn off" inflammation.
The goal is to manage symptoms, support recovery, restore movement, and help you get back to the activities that matter to you.
Frequently Asked Questions
Does laser therapy reduce inflammation?
Photobiomodulation may influence inflammatory signaling and other biological processes associated with inflammation. However, clinical evidence is inconsistent across conditions, so it is more accurate to describe laser therapy as potentially modulating inflammatory processes rather than eliminating inflammation.
Does laser therapy reduce swelling?
It may help with some biological processes associated with swelling, but the effectiveness depends on the cause of the swelling and the patient's overall treatment plan.
Does laser therapy help pain?
Yes. Research supports potential pain-relieving effects of photobiomodulation for several musculoskeletal conditions, although the certainty of evidence varies.
Can Class IV laser reduce inflammation?
High-intensity laser therapy may have anti-inflammatory effects, but more power does not automatically mean better results. Treatment parameters and the patient's condition are important.
Can laser therapy replace exercise?
No. Laser therapy should generally be considered an adjunct to active rehabilitation rather than a replacement for strengthening, mobility, and functional training.
How many laser therapy sessions will I need?
There is no universal number. Treatment frequency depends on the condition, treatment parameters, response to treatment, and overall rehabilitation plan.
Is laser therapy safe?
Therapeutic laser is generally considered non-invasive when appropriately administered, but appropriate safety precautions are necessary. A physical therapist should determine whether it is appropriate for your individual situation.
Comments