Red Light Therapy (RLT), also known as photobiomodulation (PBM), is a non-invasive treatment that uses specific wavelengths of light, typically in the red (620–700 nanometers) and near-infrared (780–1200 nanometers) spectrums. These low-level light waves penetrate the skin and underlying tissues without generating significant heat. Research suggests RLT may be a useful complementary approach for persistent issues like back pain by influencing cellular processes that contribute to pain and tissue repair.
How Red Light Therapy Works at the Cellular Level
The mechanism by which RLT exerts its effects begins inside the cell’s energy factories, the mitochondria. When the red and near-infrared photons penetrate the tissue, they are absorbed by a molecule within the mitochondria called cytochrome c oxidase. This absorption acts as a stimulus, which helps to optimize the cell’s energy production cycle.
The result of this stimulation is an increase in the production of adenosine triphosphate (ATP), the primary energy currency for cellular activities. With more available ATP, cells function more efficiently, accelerating the natural processes of repair and regeneration in damaged tissues. The light also helps to modulate inflammation by reducing oxidative stress and suppressing pro-inflammatory signaling molecules.
This process promotes the release of nitric oxide, a molecule that signals the smooth muscles around blood vessels to relax. This vasodilation increases local blood flow to the treated area. Improved circulation enhances the delivery of oxygen and nutrients necessary for healing and the removal of metabolic waste products, supporting tissue recovery and reducing discomfort.
Research on Treating Back Pain
Clinical studies have investigated the potential of RLT to manage both acute and chronic lower back pain. For chronic non-specific low back pain, defined as pain lasting longer than three months, randomized, double-blind trials have demonstrated that RLT can lead to a reduction in pain scores and improved mobility. Some trials have shown pain reduction in chronic sufferers by approximately 50% over a few weeks of consistent use.
The effectiveness depends on using proper light parameters, specifically the correct wavelength and power density, to ensure sufficient penetration to deep tissues. Near-infrared light (800–1200 nm) is favored for back pain because it travels deeper than visible red light, reaching the spinal structures and nerves. The anti-inflammatory effect of RLT is particularly helpful in chronic conditions like degenerative disc disease or spinal arthritis by reducing stiffness and supporting deep tissue healing.
For acute pain, such as from a recent muscle strain or injury, RLT appears to offer more immediate analgesic effects. This quick relief is due to the light’s ability to modulate nerve signals, raising the activation threshold of pain fibers. The therapy is considered a complementary tool that works best when combined with movement, exercise, and other standard physical therapies.
Practical Application and Treatment Protocols
When using RLT for back pain, the light must be positioned close to the skin, often within six inches, to ensure adequate light energy reaches the target tissues. For deeper back structures, devices that emit near-infrared light are preferred because these longer wavelengths penetrate more effectively. The treatment protocols typically involve exposing the painful area for a session duration of 10 to 20 minutes.
Consistency is a significant factor in achieving results, with most protocols recommending treatment on a frequent schedule, such as three to five times per week. For chronic conditions, this consistent regimen may need to be followed for three to four weeks before initial relief is noticed, and ongoing maintenance use may be required. Devices used in a clinical setting, such as high-intensity lasers, are more powerful and precise, often leading to faster results with fewer sessions.
At-home devices, which include panels, belts, and handheld units, typically operate at lower power levels for safety and ease of unsupervised use. These consumer devices may require slightly longer session times or a greater number of weekly sessions to deliver a comparable cumulative dose of light energy. Correct positioning is key, such as using a flexible belt that contours to the lumbar spine or leaning back against a mounted panel.
Safety and When to Avoid Red Light Therapy
RLT is generally considered safe for most people because it is non-thermal, meaning it does not heat or burn the skin like UV light. Side effects are rare and typically mild, sometimes involving temporary redness or warmth in the treated area. However, there are specific situations, known as contraindications, where the therapy should be avoided or used with caution.
One primary concern is use over active cancerous lesions or in individuals with active cancer, as the light’s cell-stimulating properties could theoretically promote tumor growth. RLT is also not recommended for use over the abdominal or pelvic region during pregnancy due to the lack of extensive safety data on the developing fetus.
People with conditions that increase photosensitivity, such as lupus, or those taking photosensitizing medications like certain antibiotics, should consult a healthcare provider first. It is also advisable to avoid directing the light over the thyroid gland in the neck, as its effects on hormone regulation are not fully understood.
While many devices are safe for the eyes, using appropriate eye protection, such as the goggles provided with the device, is a necessary safety measure to protect the retina from intense light exposure. Individuals with medical implants or pacemakers should also seek professional guidance before treatment.