What is Infrared light therapy? What is the Difference Between Red Light vs. Near Infrared Therapy?

What Is Infrared Light Therapy?

Infrared light therapy is a form of phototherapy that uses specific wavelengths of infrared light to support cellular function and promote health benefits. Infrared light is part of the electromagnetic spectrum just beyond visible red light and is invisible to the human eye. We naturally experience infrared radiation as gentle radiant heat from sunlight.

Beyond its warming effect, infrared light also interacts with biological tissues at the cellular level, influencing circulation, metabolism, and tissue repair.

The infrared spectrum ranges from approximately 700 nm to 1 mm in wavelength and is commonly divided into near infrared (NIR), mid infrared (MIR), and far infrared (FIR). Each range interacts with the body differently based on its wavelength and tissue absorption characteristics.

Near, Mid, and Far Infrared: Key Differences

Near Infrared (NIR): 700 – 1400 nm

Near infrared light sits closest to the visible spectrum and is known for its strong photobiomodulation effects. Unlike longer infrared wavelengths, NIR can penetrate relatively deeply into muscles and joints while producing only mild surface heating.

Research shows that wavelengths in the 760 – 900 nm range are efficiently absorbed by mitochondria, where they stimulate cytochrome c oxidase activity. This can:

• Enhance cellular energy (ATP) production

• Support tissue repair and recovery

• Reduce inflammation and oxidative stress

These effects make NIR particularly useful for muscle recovery, joint discomfort, and deep tissue support.

Mid Infrared (MIR): 1400 – 3000 nm

Mid infrared wavelengths are absorbed more readily by water in the skin and soft tissues. This results in stronger thermal effects and moderate tissue penetration.

MIR therapy is primarily associated with:

• Promoting vasodilation (widening of blood vessels)

• Improving local circulation

• Helping relax muscles and relieve stiffness

Its benefits are mainly linked to controlled therapeutic heating rather than direct cellular stimulation.

Far Infrared (FIR): 3000 nm – 1 mm

Far infrared wavelengths are absorbed at the surface of the skin and converted efficiently into deep, resonant heat within tissues. While FIR itself does not penetrate as deeply as NIR in optical terms, its energy is transferred into the body through thermal conduction, allowing heat to reach deeper muscle layers.

Far infrared therapy is associated with:

• Improved blood circulation

• Muscle relaxation and pain relief

• Reduced fatigue and stiffness

• Cardiovascular support through heat-induced vascular conditioning

FIR is widely used in heating pads and infrared saunas due to its comfort, safety, and ability to provide uniform therapeutic warmth.

Heat Therapy and Systemic Health Benefits

Thermal exposure from infrared therapy produces physiological effects similar to moderate exercise, including:

• Improved cardiovascular function

• Increased circulation and oxygen delivery

• Release of endorphins for relaxation and mood support

• Enhanced sleep quality and immune response

In addition to heat effects, emerging research suggests that mid and far infrared wavelengths may influence cellular water structure and microcirculation, though these non-thermal mechanisms are still under investigation.

Red Light vs. Near Infrared Therapy

Red light therapy and near infrared therapy are often grouped together, but they operate in different regions of the light spectrum and serve complementary roles.

Shorter wavelengths (red light) are absorbed mainly by the skin, making them ideal for:

• Skin rejuvenation

• Collagen production

• Surface tissue repair

Longer wavelengths (near infrared) penetrate more deeply into muscle and joint tissues, supporting:

• Pain relief

• Inflammation reduction

• Cellular recovery

Different tissues absorb different wavelengths, which is why combining red and near infrared light offers broader therapeutic coverage.

Why LED Technology Is Optimal for NIR Therapy

LED-based near infrared systems offer several advantages over lasers and halogen lamps:

• Precise wavelength control

• Low surface temperature for safety

• Even light distribution over larger treatment areas

• Gentle energy delivery measured in milliwatts (mW), reducing burn and eye injury risk

This allows consistent, safe, and effective treatments suitable for home and clinical use.

Cellular Mechanism of Near Infrared Therapy

NASA-supported research has demonstrated that near infrared light can penetrate deeply into body tissues and influence mitochondrial function. Inside each cell, mitochondrial chromophores absorb NIR photons, triggering:

• Increased ATP (cellular energy) production

• Enhanced protein and collagen synthesis

• Reduced oxidative stress

• Accelerated tissue repair and regeneration

These effects explain why NIR therapy is widely used in rehabilitation, sports recovery, and chronic pain management.

Benefits of Near Infrared Therapy

Near infrared therapy uses the shortest infrared wavelengths within the infrared spectrum. While infrared broadly spans 700 nm to 1 mm, NIR is concentrated in the 700 – 1400 nm range, where biological light absorption is optimal.

Key benefits include:

• Deep tissue pain relief

• Faster muscle recovery

• Improved circulation and oxygenation

• Reduced inflammation

• Enhanced cellular energy production

UTK provides different kinds of red light therapy devices and infrared heating pads. Learn more at www.utktechnology.com