Near Infrared Light Therapy (NIR LT) is a non-invasive treatment that utilizes specific wavelengths of light to stimulate biological processes. This therapy typically employs light in the 700 to 1100 nanometer (nm) range, which is invisible to the human eye. The longer wavelength of NIR light allows it to penetrate deeper into biological tissues compared to visible light. This deep penetration enables the delivery of therapeutic energy to muscles, joints, nerves, and even bone, without causing thermal damage.
The Cellular Mechanism of Near Infrared Light
The biological effects of Near Infrared Light Therapy are explained by photobiomodulation (PBM), which describes how light energy interacts with cellular components. The primary target for light absorption is the mitochondria, often called the “powerhouse” of the cell. Specifically, the enzyme Cytochrome c Oxidase (CCO) in the mitochondrial respiratory chain absorbs the NIR photons. When cells are stressed or damaged, CCO is temporarily inhibited by nitric oxide (NO). The absorption of NIR light causes this inhibitory NO to dissociate from the enzyme, allowing oxygen to bind to CCO and restoring the electron transport chain.
This restoration results in a significant increase in the production of Adenosine Triphosphate (ATP). Increased ATP enhances cellular metabolism, repair, and regeneration. Furthermore, the released nitric oxide acts as a signaling molecule, causing local blood vessels to widen, which increases circulation and delivers more oxygen and nutrients to the treated area.
Therapeutic Applications
Near Infrared Light Therapy is applied across various fields because it stimulates cellular energy production and enhances localized blood flow. The depth of penetration makes it effective for conditions involving deeper tissues.
Tissue Repair and Pain Management
NIR light is widely used to address musculoskeletal issues, including chronic joint pain and muscle soreness. By enhancing cellular energy production in damaged cells, the therapy supports natural repair mechanisms necessary for muscle recovery after intense physical activity. This enhanced function helps reduce the time needed for tissues to heal and regenerate. The therapy also helps manage inflammation, which is a common cause of chronic pain. The improved microcirculation aids in the removal of inflammatory byproducts from the injured tissue. This anti-inflammatory and circulatory effect provides temporary relief from minor muscle and joint pain, stiffness, and muscle spasms.
Dermatological and Aesthetic Uses
Although red light is often highlighted for surface skin issues, the deeper penetration of NIR light offers distinct benefits for underlying skin structures. NIR wavelengths reach the dermis and hypodermis, stimulating fibroblasts responsible for producing collagen and elastin. This action supports skin rejuvenation by improving elasticity and reducing the appearance of deeper wrinkles. For wound healing, NIR light accelerates the cellular proliferation needed to close wounds and repair damaged skin layers. The therapy also contributes to scar management by supporting the organization and synthesis of new tissue.
Neurological Potential
A more emerging area is the use of NIR light for transcranial photobiomodulation, which targets the brain through the skull. NIR wavelengths are among the few that can pass through the scalp and bone to reach cortical tissue. This application aims to stimulate neuronal mitochondria and improve cerebral blood flow, which may support cognitive function and mood. Research suggests potential for managing symptoms related to certain neurological and psychological conditions. The non-invasive nature of NIR light offers a promising avenue for future support of brain health.
Practical Usage and Safety Considerations
When considering the use of Near Infrared Light Therapy, whether through clinical or home units, understanding proper usage and safety protocols is important. Devices range from small handheld units to full-body chambers, and their effectiveness depends on specific physical parameters.
Device Selection and Protocols
Effective devices must deliver the appropriate power output, known as irradiance, to ensure the light penetrates deeply enough to reach the target tissue. Optimal therapeutic effects are typically achieved with wavelengths centered around 810 nm and 850 nm. It is helpful to select devices registered or cleared by regulatory bodies, such as the FDA, as this indicates the product has met safety standards. Session duration and frequency vary widely, but typical sessions often last between 5 and 20 minutes. Consistency is emphasized, with many protocols suggesting treatments multiple times per week for several weeks to achieve sustained results.
Safety and Contraindications
Eye protection is strongly recommended when using high-output NIR devices, especially when treating the face or head. Because NIR light is invisible, it does not trigger the natural blink reflex, and prolonged exposure can cause retinal damage. Specialized goggles are necessary to block the specific NIR wavelengths. Certain health conditions and medications require caution or make the therapy inadvisable. Individuals taking photosensitizing medications, such as some antibiotics, should avoid therapy as it may increase the risk of skin irritation or burns. Treatment should also be avoided directly over a known malignancy or active tumor, as the cell-stimulating effects of PBM could accelerate growth. Caution is advised for pregnant individuals, with recommendations to avoid direct treatment over the abdomen, and for individuals with hyperthyroidism to avoid treatment on the neck area.