What Is Red Light Therapy And Near-Infrared Light Therapy/Photobiomodulation?

Electromagnetic waves range from 0.0001 nanometer (gamma rays and x-rays are very small waves) all the way to over centimeters and meters (radar and radio waves).

If you pass white light (like sunlight) through a prism, it will separate out the different colors based on their wavelengths. This is how we get rainbows as well, and you might remember this from school with the acronym ROY. G. BIV, which stands for red, orange, yellow, green, blue, indigo, violet.

A tiny part of this spectrum – from roughly 400nm to 700nm – is visible to the human eye.

At the highest end of the visible light spectrum is red light, which goes from a little over 600nm to approximately 700nm. Above the visible light spectrum is near-infrared, from about 700nm to a little over 1,100nm.

It is the red and near-infrared wavelengths specifically that have these amazing effects on our bodies. (Interestingly, even within that range, not all the red and near-infrared wavelengths seem to be created equal. Specifically, most research showing benefits of red light and near-infrared light have used wavelengths in the narrow ranges of 630-680nm and 800-880nm.)

While most other wavelengths of light (such as UV, blue, green, and yellow light, etc.) are mostly unable to penetrate into the body and stay in the layers of the skin, near-infrared light and red light are able to reach deep into the human body (several centimeters, and close to 2 inches, in some cases) and are able to directly penetrate into the cells, tissues, blood, nerves, the brain, and into the bones.

Once in those deeper tissues, red light and near-infrared (NIR) light have incredible healing effects on the cells where they can increase energy production, modulate inflammation, relieve pain, help cells regenerate faster, and much more.

 The important question to answer is “how the heck does red and near-infrared light actually cause these effects?”

We know how UV light affects us, for example – it works primarily by interacting with our skin and stimulating the production of vitamin D. We also know how blue light enters our eyes and feeds back into the circadian clock in our brain (in the suprachiasmatic nucleus) to regulate our 24-hour biological rhythm, including the complex array of hormones and neurotransmitters that are regulated by this circadian clock in our brain.

These mechanisms are well understood by science. But what about red/NIR light?

Two Key Mechanisms of NIR And Red Light Therapy

I generally think of photobiomodulation as having two central mechanisms in how it benefits cellular function and overall health:

1. Stimulating ATP production in the mitochondria through interacting with a photoreceptor called cytochrome c oxidase.

2. Creating a temporary, low-dose metabolic stress that ultimately builds up the anti-inflammatory, anti-oxidant and cell defense systems of the cell (known as hormesis, which is also a primary mechanism of why exercise works).

Mechanism #1: Stimulating Mitochondrial Energy Production

This point deserves special attention, because a huge amount of research in the last decade points to the mitochondria as being critical to health, disease prevention, energy levels, and longevity. The mitochondria are the batteries that fuel all the processes of our organs; thus, things which enhance the mitochondria translate into more cellular energy inside the cell, which allows the cell or organ (e.g. brain, heart, liver, skin, muscles, etc.) to work optimally.

When it comes to red/NIR, the photoacceptor cytochrome c oxidase in our mitochondria is of particular importance.

Cytochrome c oxidase is part of the respiratory chain in our mitochondria that is responsible for producing ATP (cellular energy). When red and near-infrared light photons hit the photoacceptor cytochrome c oxidase, it helps the mitochondria use oxygen more efficiently to produce ATP.

While the exact mechanisms are still debated, most researchers believe that nitric oxide (NO) plays a central role.

• Hamblin, M. (2008). The role of nitric oxide in low level light therapy. Proceedings of SPIE – The International Society for Optical Engineering 6846 · February 2008 with 2,541 Reads DOI: 10.1117/12.764918

• Hamblin, M, et al. (2018). Low-level light therapy: Photobiomodulation. Society of Photo-Optical Instrumentation Engineers (SPIE).

NO of course plays many vital roles in the body, but when we have too much of it, too much in the wrong place, or when our cells don’t have the antioxidant capacity to quell the buildup of NO, it can hinder ATP from being manufactured in the mitochondria. 

• Hamblin, M. (2008). The role of nitric oxide in low level light therapy. Proceedings of SPIE – The International Society for Optical Engineering 6846 · February 2008 with 2,541 Reads DOI: 10.1117/12.764918

How?

Nitric oxide begins to compete with oxygen in the mitochondria.

In fact, NO binds with cytochrome c — preventing it from binding with oxygen. It basically blocks the oxygen from being used by the mitochondria. Because of this, the NO inhibits efficient ATP production.

As shown by several research groups around the world, red and near-infrared light essentially prevents this pairing of NO with cytochrome c oxidase. It knocks the NO out and lets the oxygen in!

In essence, photobiomodulation allows oxygen into the mitochondria (and prevents NO from halting energy production).

• Farivar, S. et al. (2014). Biological Effects of Low Level Laser Therapy. Journal of Lasers in Medical Science.

This boosts mitochondrial function and helps improve the health of every organ and system in our body.

Mechanism #2: Hormesis

Another key mechanism for how near-infrared and red light therapy work is through hormesis. Hormesis is the process by which a transient metabolic stressor stimulates adaptations that actually improve health.

This may sound like an odd concept at first, but you’re more familiar with it than you realize – exercise is a type of hormesis. Exercise works by transiently creating metabolic stress – stressing out the body (workouts are hard work!) and temporarily increasing reactive oxygen species, a.k.a. free radicals – and then in response to that stress, the body adapts to it with things like improved cardiovascular efficiency, improved blood delivery to the muscles, and by strengthening and growing the mitochondria.

It also involves downregulating the genes involved in chronic inflammation and oxidative stress (two keys drivers of aging and disease), and upregulating the genes involved in energy production and the internal cellular antioxidant defense system.

It turns out that humans actually need some of these low-level stressors in their life. The absence of these stressors actually sabotages our health.

Light serves a transient low-level stress to your cells. The end result of these cellular adaptations to the temporary stress is healthier cells that produce more energy, have a stronger anti-oxidant and anti-inflammatory defense system, and are more resilient to overall stress.

So near-infrared and red light therapy also are a form of hormesis, and benefit the mitochondria by creating a low dose stressor that the body then adapts to by becoming even stronger – the body increases production of internal antioxidant and anti-inflammatory systems, and builds up the size and strength of mitochondria.

In this way, red/NIR light become a powerful tool that doesn’t just temporarily alleviate symptoms (like say, an anti-inflammatory or painkiller drug), but it stimulates your body making lasting adaptations at the cellular level that lead to more resilience against stressors and a greater capacity to produce energy.

Mechanisms Summary

In essence, what this all boils down to is that near-infrared and red light therapy help mitochondria produce more energy, decrease inflammation, and help build the cell defense systems to increase resiliency.

Thus, the reason it can benefit so many radically different health issues is actually quite simple: The health of every organ and every cell in the body depends on the energy being produced by the mitochondria in those cells. Thus, because red/NIR light therapy work to enhance mitochondrial energy production in essentially every type of cell in the body, it can enhance the cellular processes and cellular health of potentially almost every type of cell in the body.