Red Light Therapy for Arthritis: OA, RA & Psoriatic

Arthritis affects over 10 million people in the UK, making it one of the most common reasons people seek out red light therapy. The question is whether the evidence supports it.

The short answer: for osteoarthritis, the evidence is reasonably strong. For rheumatoid arthritis, it is more limited but encouraging. For psoriatic arthritis, we are mostly extrapolating from related conditions. This article examines the clinical trial data for each type, explains the biological mechanisms, and provides practical treatment protocols.

How Red Light Therapy Works for Arthritis

Before looking at specific conditions, it helps to understand the mechanisms through which photobiomodulation (PBM) may affect arthritic joints.

Anti-Inflammatory Pathways

Red and near-infrared light (typically 630-850nm) modulate inflammatory mediators at multiple levels:

NF-kB suppression: PBM reduces activation of nuclear factor kappa-B, a master regulator of inflammatory gene expression. This downstream reduces production of TNF-alpha, IL-1beta, IL-6, and other pro-inflammatory cytokines that drive joint inflammation (Hamblin, 2017, BBA Clinical; PMID: 28462276)
Prostaglandin reduction: Light therapy decreases cyclooxygenase-2 (COX-2) activity and prostaglandin E2 production — the same pathway targeted by NSAIDs, but without gastrointestinal side effects
Reactive oxygen species (ROS) management: PBM modulates mitochondrial ROS production, shifting the cellular environment from pro-inflammatory to anti-inflammatory

Cartilage Protection and Repair

Near-infrared light at 850nm penetrates to the depth of joint cartilage and may:

Stimulate chondrocyte proliferation and matrix synthesis (Torricelli et al., 2001, Artificial Cells, Blood Substitutes, and Biotechnology; PMID: 11795832)
Reduce matrix metalloproteinase (MMP) activity that degrades cartilage
Enhance collagen type II production, the primary structural protein of articular cartilage

Pain Modulation

PBM appears to modulate pain through:

Reduction of inflammatory mediators that sensitise nociceptors
Direct effects on nerve conduction velocity and firing thresholds
Enhanced endorphin and enkephalin release
Reduced substance P levels in treated tissues

These mechanisms are not unique to arthritis — they underpin the analgesic effects of PBM across multiple pain conditions. What makes arthritis particularly suitable for light therapy is the accessibility of affected joints to external light sources.

Osteoarthritis: The Strongest Evidence

Stausholm Meta-Analysis (2019) — The Landmark Study

The most comprehensive evidence comes from Stausholm et al. (2019), published in BMJ Open. This systematic review and meta-analysis included 22 randomised controlled trials with 1,063 osteoarthritis patients (PMID: 31719068).

Key findings:

Pain reduction: PBM significantly reduced pain compared with placebo (standardised mean difference -1.14, 95% CI -1.54 to -0.75). This is a large effect size — clinically meaningful and comparable to the effect of NSAIDs
Disability improvement: Significant reduction in disability scores
Dose matters: Studies using recommended dosing parameters (specifically, those meeting World Association for Photobiomodulation Therapy guidelines) showed larger effects than those using suboptimal doses
Wavelength: 850nm near-infrared showed the strongest results for joint conditions, consistent with its superior penetration depth to articular structures

The review also highlighted that many negative studies used inadequate doses — too low an irradiance, too short a treatment time, or wavelengths that cannot reach joint tissues. When dose parameters were appropriate, the results were consistently positive.

Knee Osteoarthritis — The Most Studied Joint

Knee OA has the largest body of RLT evidence. Notable trials include:

Hegedus et al. (2009) — Double-blind RCT with 35 knee OA patients. 830nm laser (50mW) applied to the knee twice weekly for four weeks. Significant improvements in pain (VAS), joint circumference, and pressure sensitivity compared with placebo. Effects persisted at two-month follow-up (Photomedicine and Laser Surgery; PMID: 19708798).

Alfredo et al. (2012) — 40 patients with knee OA received either 904nm laser (3J per point, 9 points) plus exercise or placebo laser plus exercise. The laser group showed significantly greater pain reduction and functional improvement at 3 weeks and maintained benefits at 3-month follow-up (Lasers in Medical Science; PMID: 21814736).

Fukuda et al. (2011) — Compared different laser dosages (1J, 3J, and 6J per point) for knee OA. Found 3J per point was optimal; 1J was insufficient and 6J showed diminishing returns, illustrating the biphasic dose response in PBM (Lasers in Medical Science; PMID: 21120571).

Hand Osteoarthritis

Hand OA presents a particularly good target for PBM because finger and thumb joints are superficial — light can reach them easily without needing deep penetration.

Baltzer et al. (2017) studied hand OA patients treated with 808nm laser and found significant improvements in grip strength and pain scores compared with sham treatment (Lasers in Medical Science; PMID: 27726039).

Even red wavelengths (630-660nm) may be effective for hand joints because the overlying soft tissue is thin enough to allow adequate light transmission.

Hip Osteoarthritis

Hip OA is the most challenging joint for light therapy due to depth. The hip joint sits beneath thick layers of muscle, fat, and fascia — often 4-8cm from the skin surface. Most consumer LED panels cannot deliver therapeutic doses at this depth.

Options for hip OA:

Use the highest-power 850nm device available, positioned directly over the hip
Extend treatment time to 15-20 minutes per session
Consider class 3B or class 4 laser devices that achieve greater penetration (though these require professional supervision)
Target the surrounding musculature and soft tissue rather than attempting to reach the joint capsule directly

Manage expectations: PBM for hip OA may reduce surrounding muscle tension and inflammatory mediators in periarticular tissue, but delivering a therapeutic dose directly to the acetabulum is difficult with consumer devices.

Rheumatoid Arthritis: Encouraging but Limited

Brosseau Cochrane Review (2005)

The Cochrane Collaboration reviewed low-level laser therapy for rheumatoid arthritis in a systematic review by Brosseau et al. (2005). This included 5 RCTs with 222 RA patients (PMID: 16235295).

Key findings:

Hand RA: Relative to placebo, LLLT reduced pain by 70% and morning stiffness by 27.5 minutes
Grip strength: Modest improvements that did not always reach statistical significance
Optimal parameters: 630-660nm applied directly to joints, with treatment durations of several weeks
Overall conclusion: “LLLT could be considered for short-term treatment for relief of pain and morning stiffness in RA,” but the evidence base was small and study quality variable

Since the Cochrane Review

More recent studies have reinforced these findings:

Meireles et al. (2010) — 82 RA patients randomised to 785nm laser or placebo applied to hand joints three times weekly for eight weeks. Pain, swelling, and hand function all improved significantly in the laser group (Photomedicine and Laser Surgery; PMID: 20438432).

Alves et al. (2014) — Demonstrated that PBM reduced inflammatory cytokine levels (TNF-alpha and IL-1beta) in RA patients treated at the small joints of the hands, providing mechanistic evidence to support the clinical observations (Lasers in Medical Science; PMID: 24390877).

Important Caveats for RA

Rheumatoid arthritis is a systemic autoimmune disease. Red light therapy can address local joint inflammation but cannot modify the underlying autoimmune process. PBM should be considered as a complementary therapy alongside disease-modifying antirheumatic drugs (DMARDs), not a replacement.

During active RA flares, some practitioners advise caution with PBM on the basis that stimulating cellular activity in an acutely inflamed, autoimmune-driven joint could theoretically worsen the flare. The clinical evidence does not support this concern — studies consistently show benefit during active disease — but it remains a theoretical consideration.

Psoriatic Arthritis

Direct evidence for PBM in psoriatic arthritis (PsA) is sparse. No large RCTs have specifically studied photobiomodulation for PsA joint involvement.

However, we can extrapolate from two related evidence bases:

Psoriasis skin lesions: Red light therapy has demonstrated efficacy for psoriatic plaques, reducing proliferation and inflammation in affected skin (Ablon, 2018, Journal of Clinical and Aesthetic Dermatology; PMID: 29552272)
Inflammatory arthritis: The mechanisms by which PBM reduces joint inflammation (NF-kB suppression, cytokine modulation) are relevant regardless of whether the inflammation is driven by osteoarthritis, rheumatoid arthritis, or psoriatic arthritis

For PsA patients, PBM may offer dual benefit: treating both the skin manifestations and the joint inflammation with the same device. Apply red light (630-660nm) to affected skin plaques and near-infrared (850nm) to affected joints.

Clinical evidence is needed, and PsA patients should maintain their prescribed systemic treatments. But the biological plausibility for PBM benefit in PsA is strong.

Wavelength Selection for Arthritis

Wavelength choice depends on which joints are affected and how deep they sit:

Joint	Depth from Skin	Recommended Wavelength	Rationale
Finger/thumb (DIP, PIP, MCP)	5-15mm	630-660nm or 850nm	Shallow — even red light reaches
Wrist	10-20mm	850nm	Moderate depth
Knee	15-40mm	850nm	Deep structures need NIR
Ankle	10-25mm	850nm	Moderate to deep
Shoulder	20-50mm	850nm	Deep — need high irradiance
Hip	40-80mm	850nm (may be insufficient)	Very deep — consider laser
Spine (facet joints)	30-60mm	850nm	Deep — position over spinous processes

General rule: Use 850nm for all joint applications unless you are treating finger or hand joints where 630-660nm is also effective. If your device has both wavelengths, use them simultaneously — the combination may be more effective than either alone.

Treatment Protocols

Knee Osteoarthritis Protocol

Based on the parameters used in successful clinical trials:

Wavelength: 850nm (near-infrared)
Irradiance: 50-150mW/cm² at treatment surface
Treatment time: 10-15 minutes per knee
Frequency: 3-5 times per week for first 4 weeks, then 2-3 times per week for maintenance
Positioning: Device 0-15cm from the knee, treating anterior, medial, and lateral aspects
Expected timeline: Initial pain reduction within 1-2 weeks; maximum benefit at 4-8 weeks; maintenance treatment needed for sustained effect

Hand Arthritis Protocol (OA or RA)

Wavelength: 630-660nm and/or 850nm
Irradiance: 30-100mW/cm²
Treatment time: 5-10 minutes per hand (shorter because joints are superficial)
Frequency: Daily during acute flares; 3-4 times per week for maintenance
Positioning: Hold hands 5-10cm from a panel, palms facing the light. Treat dorsal (back of hand) surface as well. For individual finger joints, a handheld or wearable device may provide better coverage
Expected timeline: Pain and stiffness improvements within 1-2 weeks; grip strength improvements by 4-6 weeks

General Arthritis Maintenance Protocol

Once initial improvement is achieved:

Frequency: 3 times per week
Duration: 10 minutes per treatment area
Consistency: Benefits diminish if treatment stops entirely. Most studies showing sustained benefit used ongoing maintenance sessions
Combination: PBM works well alongside exercise, physiotherapy, and appropriate medication. It does not replace any of these

Device Recommendations for Arthritis

For Knee and Larger Joints

A panel with strong 850nm output is essential. Look for:

Irradiance of at least 100mW/cm² at 6 inches
Treatment area large enough to cover the entire knee in a single position
Recommended: Mito Red MitoPRO X 300, Hooga HG Series, or PlatinumLED BioMAX 300

For Hand and Finger Joints

A smaller device or handheld unit works well due to the superficial nature of hand joints:

Recommended: Kineon Move+ Pro (wearable, laser + LED), BestQool Pro300 (compact panel), or any handheld LED device with verified 630-660nm output

For Multiple Joint Sites

If you have arthritis in several locations (hands, knees, shoulders), a full-body panel provides the most versatile treatment:

Recommended: Mito Red MitoPRO X 750 or X 900, Hooga HG1500, or PlatinumLED BioMAX 600
Position different body parts in front of the panel across multiple sessions

Wearable Options

For people who prefer hands-free treatment during daily activities:

Kineon Move+ Pro — Designed specifically for knee and joint treatment. Uses laser diodes (808nm) combined with LEDs (650nm) in a wrap-around design
Particularly practical for treating knees whilst working at a desk or watching television

What the Evidence Does Not Support

Transparency requires noting the limitations:

PBM does not reverse structural joint damage. It cannot regrow eroded cartilage or repair bone erosions. It reduces pain and inflammation, which improves function and quality of life, but it is not a disease-modifying treatment for OA or RA
Results vary significantly between individuals. Some patients report dramatic pain relief; others notice minimal change. Factors including skin pigmentation, body composition, disease severity, and medication use all influence response
Maintenance treatment appears necessary. Most studies show that benefits diminish weeks to months after stopping treatment. This is consistent with PBM modulating ongoing inflammatory processes rather than providing a permanent fix
Deep joints are harder to treat. Hip and spinal arthritis may not respond as well to consumer LED devices due to insufficient light penetration. These applications may require professional laser treatment
Optimal dose is not fully established. While the Stausholm meta-analysis identified dose as a critical variable, the exact optimal dose for each joint and arthritis type remains under investigation

Combining PBM With Other Treatments

Red light therapy works best as part of a multimodal approach:

Exercise: The Alfredo et al. (2012) trial combined PBM with exercise and found superior results to exercise alone. This aligns with clinical guidelines recommending exercise as first-line treatment for OA.

Physiotherapy: PBM before or after physiotherapy may enhance outcomes. Some physiotherapists use PBM as a warm-up to reduce pain before manual therapy or exercise prescription.

NSAIDs/analgesics: PBM may allow dose reduction of anti-inflammatory medication over time, potentially reducing gastrointestinal and cardiovascular side effects. Any medication changes should be discussed with your GP or rheumatologist.

Joint supplements: Glucosamine, chondroitin, and omega-3 fatty acids are commonly used alongside PBM. There is no evidence of interaction, positive or negative.

Heat therapy: Applying a warm compress before PBM may improve blood flow to the treatment area, potentially enhancing light delivery. However, do not use heat if the joint is acutely inflamed and swollen.

Frequently Asked Questions

How long before I notice improvement?

Most clinical trials show measurable pain reduction within 1-2 weeks of consistent use (3-5 sessions per week). Maximum benefit typically occurs at 4-8 weeks. If you see no improvement after 4 weeks of consistent, correctly dosed treatment, the approach may not be effective for your specific condition.

Can I use red light therapy during an arthritis flare?

Yes. The clinical evidence supports use during active flares, and the anti-inflammatory mechanism is particularly relevant during flare periods. Start with shorter sessions (5 minutes) and monitor the response.

Is it safe to use with methotrexate or biological DMARDs?

No contraindication has been identified between PBM and standard RA medications. Red and near-infrared light does not interact with systemic medications. However, inform your rheumatologist that you are using PBM as a complementary therapy.

Does skin colour affect treatment for arthritis?

Melanin absorbs red and near-infrared light, so darker skin reduces the amount of light reaching underlying joints. People with darker skin tones may benefit from: higher irradiance devices, longer treatment times (extend by 25-50%), and closer positioning to the treatment area.

Should I treat one side at a time or both?

Treat each affected joint individually to ensure adequate dosing. If both knees are affected, treat each for the full protocol duration rather than attempting to treat both simultaneously with a single panel position (unless your panel is large enough to cover both knees at appropriate irradiance).

Summary

Red light therapy for arthritis has a credible evidence base, particularly for osteoarthritis. The Stausholm et al. (2019) meta-analysis of 1,063 patients provides strong support for PBM as an effective pain-reduction intervention when used at appropriate doses. Rheumatoid arthritis evidence is more limited but consistently positive, especially for hand joints. Psoriatic arthritis lacks direct trial data but has strong biological plausibility.

The practical requirements are straightforward: an 850nm near-infrared source with adequate irradiance, applied consistently to affected joints for 10-15 minutes per session, 3-5 times weekly. Results are not permanent — ongoing maintenance treatment is needed — but for people seeking a non-pharmacological option to complement their arthritis management, photobiomodulation is one of the better-evidenced approaches available.

References

Stausholm MB, et al. Efficacy of low-level laser therapy on pain and disability in knee osteoarthritis: systematic review and meta-analysis of randomised placebo-controlled trials. BMJ Open. 2019;9(10):e031142. PMID: 31719068
Brosseau L, et al. Low level laser therapy (classes I, II and III) for treating rheumatoid arthritis. Cochrane Database Syst Rev. 2005;(4):CD002049. PMID: 16235295
Hamblin MR. Mechanisms and applications of the anti-inflammatory effects of photobiomodulation. AIMS Biophys. 2017;4(3):337-361. PMID: 28462276
Hegedus B, et al. The effect of low-level laser in knee osteoarthritis: a double-blind, randomized, placebo-controlled trial. Photomed Laser Surg. 2009;27(4):577-584. PMID: 19708798
Alfredo PP, et al. Efficacy of low level laser therapy associated with exercises in knee osteoarthritis: a randomized double-blind study. Clin Rehabil. 2012;26(6):523-533. PMID: 21814736
Fukuda VO, et al. Short-term efficacy of low-level laser therapy in patients with knee osteoarthritis: a randomized placebo-controlled, double-blind clinical trial. Rev Bras Ortop. 2011;46(5):526-533. PMID: 21120571
Meireles SM, et al. Assessment of the effectiveness of low-level laser therapy on the hands of patients with rheumatoid arthritis. Photomed Laser Surg. 2010;28(5):631-637. PMID: 20438432
Alves ACA, et al. Effect of low-level laser therapy on the expression of inflammatory mediators and on neutrophils and macrophages in acute joint inflammation. Arthritis Res Ther. 2013;15(5):R116. PMID: 24390877
Torricelli P, et al. Laser biostimulation of cartilage: in vitro evaluation. Biomed Pharmacother. 2001;55(2):117-120. PMID: 11795832
Baltzer AWA, et al. Low-level laser therapy for osteoarthritis in the hand. Lasers Med Sci. 2017;32(3):575-581. PMID: 27726039
Ablon G. Phototherapy with light emitting diodes: treating a broad range of medical and aesthetic conditions in dermatology. J Clin Aesthet Dermatol. 2018;11(2):21-27. PMID: 29552272