Red light therapy (RLT), also known as photobiomodulation or low-level laser therapy, has recently gained attention as a potential treatment for certain types of chronic and acute pain.
This article will examine the evidence behind using RLT for pain relief, how it works, what types of pain it may help with, and considerations for use.
What is Red Light Therapy?
Red light therapy involves exposing the body to low-level red and near-infrared light for a range of potential benefits, including wound healing, skin rejuvenation, and pain relief. The light is delivered via LEDs or lasers in specific wavelengths that are thought to have anti-inflammatory and tissue regeneration effects.
***Wavelengths used*** | 660 nm (red) and 850 nm (near-infrared) |
***Power density*** | Energy delivered is low-level, from 10-100 mW/cm2 |
Unlike ultraviolet light which damages skin, RLT when administered properly does not burn or harm human tissue.
The low-level light is thought to act on cytochrome c oxidase in mitochondria to increase ATP production and reduce oxidative stress. This leads to downstream benefits at a cellular level.
How RLT Helps Relieve Pain
There are several ways RLT may help reduce acute and chronic pain:
Anti-Inflammatory Effects
By increasing ATP and reducing oxidative stress, RLT can calm inflammation which often underlies chronic pain conditions. The light may also limit the production of inflammatory cytokines.
Improved Circulation
RLT can enhance microcirculation to bring more oxygen and nutrients to painful tissue while clearing inflammatory mediators.
Accelerated Healing
The light promotes tissue regeneration and nerve cell growth by increasing collagen production and growth factors. This facilitates healing from injuries or chronic conditions.
Increased Beta-Endorphins
One study showed RLT raised beta-endorphin levels, the body’s natural pain-relieving compounds. This helps dampen pain signals to the brain.
Effective for These Pain Conditions
Based on the mechanisms above, research indicates RLT could help certain pain types:
Joint Pain
RLT reduced arthritis pain and stiffness in several studies of knee osteoarthritis patients. It lowered inflammatory markers and improved physical function.
Neck, Back or Muscle Pain
Smaller studies found RLT decreased chronic back and neck pain, while a few reports noted less post-workout muscle soreness.
Neuropathic Pain
NERVE damage often underlies hard-to-treat neuropathic pain. By healing nerves, RLT reduced neuropathic pain related to diabetes, chemotherapy, and nerve injuries in some research.
Acute Injuries
Sprains, strains, or contusions causing inflammation and pain may benefit from RLT’s tissue healing and anti-inflammatory effects. More data is still needed, however.
RLT Treatment Protocol for Pain
If pursuing RLT for pain relief, optimizing treatment factors can enhance effectiveness:
Wavelength
Use red light around 660 nm and near-infrared light around 850 nm. These wavelengths have the greatest tissue penetration depth to reach painful areas.
Power Density
Most devices should emit light at 40-50 mW/cm2 or 4-5 J/cm2. Higher irradiances above 100 mW/cm2 provide no added benefit and may be unsafe.
***Timing*** | ***Several minutes per area up to 30 minutes maximum in one session.*** Breaking up the dose prevents heat/discomfort. |
***Frequency*** | ***5-6 sessions per week for several weeks.*** Effects accumulate so consistency matters. |
Application Method
Using a multi-LED full-panel device allows wide bodily coverage at once. For localized pain, spot treatment with smaller handheld or single-diode units may work better.
Combine Other Therapies
Simultaneously applying heat, ice, pressure, or massage during RLT could boost outcomes by enhancing light penetration. Ultrasound therapy alongside RLT also showed promise for relieving knee arthritis in one study.
Is RLT Safe?
RLT has an excellent short-term safety profile when properly administered to avoid overheating tissue. Longer-term risks still require evaluation. Protective goggles should be worn to prevent eye damage from bright light.
Those with light-reactive conditions, skin cancers, or taking photosensitizing drugs should exercise caution with RLT or avoid it given lack of safety data. Discuss using RLT with your doctor if pregnant or having other medical issues as the effects are uncertain.
The Future of RLT for Pain
Early research suggests RLT could provide non-invasive, drug-free pain relief with minimal side effects. More high-quality clinical trials are still needed to establish optimal protocols.
However, the initial findings are promising, especially for arthritic and musculoskeletal pain.
As RLT devices improve and become more refined, RLT therapy may soon play a substantial role alongside other traditional modalities like physical therapy or pain medications for managing chronic pain.
References
- Cotler, H. B., Chow, R. T., Hamblin, M. R., & Carroll, J. (2015). The use of low-level laser therapy (LLLT) for musculoskeletal pain. MOJ Orthopedics & Rheumatology. This article discusses the effectiveness of LLLT in treating musculoskeletal pain, highlighting the need for effective pain treatments. Read the article.
- de Freitas, L. F., & Hamblin, M. R. (2016). Proposed mechanisms of photobiomodulation or low-level light therapy. IEEE Journal of Selected Topics in Quantum Electronics. The paper explores the mechanisms behind photobiomodulation, including its effects on cellular function and pain relief. Read the article.
- Leal-Junior, E. C. P., Vanin, A. A., Miranda, E. F., et al. (2015). Effect of phototherapy (low-level laser therapy and light-emitting diode therapy) on exercise performance and markers of exercise recovery: a systematic review with meta-analysis. Lasers in Medical Science. This study reviews the impact of phototherapy on exercise performance and recovery, noting significant results with red light therapy. Read the article.
- Grandinétti, V. S., Miranda, E. F., Johnson, D. S., et al. (2015). The thermal impact of phototherapy with concurrent super-pulsed lasers and red and infrared LEDs on human skin. Lasers in Medical Science. This research examines the thermal effects of phototherapy on skin, considering its implications for pain relief. Read the article.