7 Red Light Therapy Benefits for Pain Relief

Written By Medford Sola

7 Evidence-Backed Benefits of Red-Light Therapy for Pain Relief

Summary:

  • Photobiomodulation (PBM; “red/near-infrared light therapy”) shows clinically meaningful pain relief in several conditions, with the strongest evidence for fibromyalgia and osteoarthritis-related pain/disability when dosed correctly.

  • Mechanisms are biologically plausible: PBM modulates mitochondrial function/ATP, photoreleases nitric oxide, reduces pro-inflammatory cytokines, improves microcirculation, and dampens neuroinflammation.

  • Dosing parameters matter (wavelength, energy per point): e.g., knee OA trials show benefits at 785–860 nm with ~4–8 J/point or 904 nm with ~1–3 J/point. Poor dosing often explains negative trials.

  • Compared with drugs, PBM offers a favorable safety profile and can be combined with exercise/rehab.

  • Evidence quality ranges from moderate (OA, neck pain, TMD, fibromyalgia) to emerging/mixed (low back pain, postoperative pain, diabetic neuropathy)—so parameter-guided use and realistic expectations are key.

Introduction

Photobiomodulation (PBM)—often called red or near-infrared (NIR) light therapy—uses non-thermal light (typically ~630–660 nm red and ~800–940 nm NIR) delivered via LEDs or low-level lasers to influence cellular signaling and tissue physiology. A recent umbrella review of systematic reviews concluded PBM appears beneficial for several conditions, with notable support in pain-related disorders (especially fibromyalgia and osteoarthritis-related disability), while emphasizing protocol heterogeneity and the need for standardization.

Below are seven pain-relief benefits with the most human data, followed by mechanisms and a practical comparison table.

1) Osteoarthritis (especially Knee OA)

  • What the evidence says: Multiple meta-analyses and clinical trials show PBM can reduce knee pain and improve function, particularly when dosimetry is within effective windows. A large BMJ Open meta-analysis reported significant improvements with 785–860 nm at ~4–8 J/point or 904 nm at ~1–3 J/point, highlighting parameter dependence. A 2024 network meta-analysis further suggested 904–905 nm wavelengths may perform best in KOA.

  • In practice: Often used as an adjunct to exercise/strength training; an RCT combining PBM with progressive strengthening showed added benefit.

2) Chronic Low-Back Pain (CLBP)

  • What the evidence says: Findings are mixed. The Cochrane review on nonspecific LBP found small, short-term pain reductions with uncertain functional gains; later meta-analysis also suggested pain relief but limited impact on function. Protocol heterogeneity is a major limitation.

  • In practice: PBM may be trialed alongside core stabilization and graded activity, with realistic expectations about magnitude/duration of benefit.

3) Chronic Neck Pain

What the evidence says: A landmark Lancet meta-analysis found low-level laser therapy reduces neck pain in both acute and chronic settings. Benefits persisted beyond the immediate treatment window in several trials.  A clinical trial in Photomedicine and Laser Surgery found that patients with chronic neck pain who received red light therapy reported significant improvements in pain relief and quality of life. The therapy was especially effective for individuals with degenerative neck conditions, providing long-term symptom relief without the need for medications.

4) Temporomandibular Disorders (TMD) / Orofacial Myalgia

  • What the evidence says: Systematic reviews show red light therapy can lower TMD-related pain, although effects on mandibular function are less consistent and short-term benefits are clearest. Protocol variability (wavelength, dose, application sites) influences outcomes across multiple independent studies.

5) Fibromyalgia (Widespread Pain)

  • What the evidence says: A 2019 meta-analysis of RCTs demonstrated significant improvements in pain, tender points, stiffness, fatigue, depression/anxiety, and Fibromyalgia Impact Questionnaire scores with PBM. More recent whole-body PBM trials (triple-blinded and feasibility studies) also reported reduced pain and better quality of life.

6) Diabetic Peripheral Neuropathy (DPN) Pain

  • What the evidence says: RCTs and systematic reviews indicate PBM can reduce neuropathic foot pain and improve nerve function (e.g., nerve conduction velocity), though the literature is smaller and more heterogeneous than for OA or fibromyalgia.

  • In practice: Often used as an adjunct to standard neuropathy care; protocols typically treat plantar surfaces and along nerve pathways.

7) Post-operative Pain and Swelling (Dental/Orthopedic)

  • What the evidence says: In oral surgery (e.g., third-molar extraction), PBM used pre-emptively or post-op can lower pain, trismus, and swelling vs. sham/placebo, per RCTs and a 2024 meta-analysis. Early orthopedic data (e.g., total knee arthroplasty) suggest reduced post-op pain and opioid use, but more trials are needed.

How PBM Reduces Pain: Mechanisms & Biological Rationale

  1. Mitochondrial modulation & ATP upshift
    Red/NIR photons interact with cytochrome-c oxidase (CCO), shifting its redox state; concurrent photodissociation of inhibitory nitric oxide (NO) from CCO can normalize respiration, improving ATP generation and cellular energetics.

  2. Nitric-oxide–mediated vasodilation & microcirculation
    PBM increases bioavailable NO, promoting vasodilation and blood/lymph flow, which can ease ischemia and facilitate clearance of inflammatory mediators.

  3. Anti-inflammatory signaling
    Clinical and preclinical work shows reductions in COX-2/PGE2, TNF-α, IL-1β/IL-6, and MMPs, with downstream effects on edema and tenderness.

  4. Neuroimmune & central effects
    PBM can attenuate neurotoxic microglial activation and modulate nociceptive pathways peripherally and centrally—helping reduce hyperalgesia/allodynia in neuropathic and inflammatory pain models.

  5. Parameter dependence (dose matters)
    Tissue optics and biphasic responses mean wavelength, fluence (J/cm²), power density, treatment time, and site critically determine outcomes—well-dosed trials show benefit, under/over-dosed often do not. KOA meta-analysis explicitly identifies effective per-point energies as above.

Practical Notes

  • Protocols: Common wavelengths are 630–660 nm (red) and 800–940 nm (NIR). For joints/tendons, many trials treat multiple points around the painful structure to a target energy per point; effective KOA ranges are ~4–8 J/point (785–860 nm) or ~1–3 J/point (904 nm).

  • Course: Typical clinical courses span 2–8 weeks, 2–3 sessions/week, then taper/maintenance based on response (per study patterns).

  • Safety: Serious adverse events are rare in the PBM pain literature; eye protection is standard for high-intensity sources.

  • Expectations: Best viewed as a complement to exercise, load management, and condition-specific care—especially where medication risks or intolerance limit options.

Peer Reviewed References:

  1. Son Y, et al. Effects of photobiomodulation on multiple health outcomes: an umbrella review of systematic reviews and meta-analyses. Systematic Reviews. 2025. BioMed Central

  2. Ibrahim MM, et al. Mechanisms and pathways of pain photobiomodulation: a narrative review. J Pain. 2021. PMC

  3. Quirk BJ, Whelan HT. What lies at the heart of photobiomodulation: light, cytochrome-c oxidase, and nitric oxide. Photobiomodul Photomed Laser Surg. 2020. PubMed

  4. Zhang R, Qu J. The mechanisms and efficacy of photobiomodulation therapy for arthritis: a comprehensive review. Int J Mol Sci. 2023.

  5. Wang X, et al. PBM inhibits neurotoxic microglia and relates to MAPK/NF-κB/TRAF6 downregulation. J Neuroinflammation. 2021. BioMed Central

  6. Stausholm MB, et al. Low-level laser therapy for knee osteoarthritis: systematic review and meta-analysis. BMJ Open. 2019.

  7. Fan T, et al. Network meta-analysis: PBM wavelengths for knee OA (904–905 nm favored). J Clin Med. 2024.

  8. Stausholm MB, et al. PBM combined with strength training in KOA: randomized trial. BMC Musculoskelet Disord. 2022. MDPI

  9. Yousefi-Nooraie R, et al. LLLT for nonspecific low-back pain: Cochrane review. Cochrane Database Syst Rev. 2008.

  10. Huang ZY, et al. Effectiveness of LLLT for nonspecific chronic LBP: systematic review & meta-analysis. Arthritis Res Ther. 2015.

  11. Chow RT, et al. Efficacy of low-level laser therapy in neck pain: systematic review & meta-analysis. Lancet. 2009. The Lancet

  12. Ahmad M, et al. LLLT in temporomandibular joint disorders: systematic review. J Lasers Med Sci. 2021. PMC

  13. Giansiracusa Rubino A, et al. PBM after third-molar removal: systematic review & meta-analysis. J Clin Med. 2024. MDPI

  14. Salaberry RS, et al. Pre-emptive PBM reduces pain after third-molar extraction: RCT. PLoS One. 2024. PLOS

  15. Yeh SW, et al. LLLT for fibromyalgia: systematic review & meta-analysis. Pain Physician. 2019. painphysicianjournal.com

  16. Chowdhury SK, et al. LLLT for painful diabetic peripheral neuropathy: randomized study. *(PubMed/PMCID report). 2015.

 

Disclaimer: The Medford Red Light Therapy website is designed and intended for general informational purposes only and does not constitute the practice of medicine, nursing or other professional health care services, including the giving of medical advice, and no doctor/patient relationship is formed. The use of information on this website is at the user’s own risk.  Results may vary by individual.  The content of this website is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Users should not disregard or delay in obtaining medical advice for any medical condition they may have and should seek the assistance of their health care professionals for any such conditions.

Medford Sola
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