How Does Light Therapy Work?
You may have heard that sunlight damage the skin; this is true with UV light. But infrared light therapy, on the other hand, provides positive effects. When the skin absorbs infrared light, it stimulates new skin cells to grow more healthily, boosting the natural healing attributes of your skin.
Numerous studies have proven that light therapy provides excellent benefits when a device combines the right wavelength of light with the right amount of power. Some of those benefits include:
Improved skin tone and complexion[1]
Enhanced muscle recovery[2]
Reduced acne, rosacea, and eczema[1]
Improved appearance of wrinkles, fine lines, scars, and stretch marks[1]
Enhanced circulation[3]
Quicker healing of wounds and injuries[3]
Reduced pain and inflammation[4]
But how does infrared light therapy produce these types of results? What’s going on in our bodies that allows for this type of healing power?
If you’ve done some research regarding the benefits of light therapy, you’ll often see the following as the rationale for its anti-aging properties:
Increased circulation, via the formation of new capillaries, is responsible for some benefits. Or, in other words, more blood and oxygen helps deliver proper nutrients to damaged areas in the body.[3]
Enhanced activity within your lymph system leads to a reduction in swelling and inflammation.[5]
Increased collagen production, which directly relates to the elasticity, firmness, and fullness of your skin.[5]
This is great information—and it makes sense. But unfortunately, most articles stop there. So, in this post, we’ll try to go a step further to answer this key question: How does red light therapy work at a cellular level?
Let’s Start With How Our Cells are Supposed to Function
All living things need to make a certain kind of cellular energy called adenosine triphosphate, or ATP. Some people even refer to ATP as the “energy currency of life.” ATP is a small molecule with a huge job: to provide usable energy for our cells. ATP is produced through cellular respiration, which includes the following four steps:
Glycolysis
Pyruvate oxidation
Citric acid cycle (aka Kreb’s cycle)
Oxidative phosphorylation
Most of this activity occurs within the mitochondria, the “powerhouse” of the cell. For the sake of this article, we’ll focus on the last step, oxidative phosphorylation. That’s where light therapy is believed to help the most.
This fourth step of cellular respiration involves an electron transport chain. As electrons move down this chain, energy is released and used to pump protons out of a matrix, forming a gradient. Protons flow back into the matrix through an enzyme called ATP synthase, which creates ATP. [6,7]
So where does ATP synthase come from? Well, a certain enzyme called cytochrome c oxidase (CCO) helps oxygen to bind with nicotinamide adenine dinucleotide (NAD) + hydrogen (H)—NADH—to form the necessary hydrogen ions that produce ATP synthase.[8] If you remember anything, make sure it’s this fact: oxygen plus NADH is a good thing when it comes to healthy cellular function.
What Happens When Our Cells Aren’t Healthy?
When we get sick, injured, stressed, etc., mitochondria in our cells can produce excess nitric oxide (NO). To understand the ramification of this, let’s go back to that little enzyme, cytochrome c oxidase.
During the creation of ATP synthase, nitric oxide competes with oxygen and binds to CCO. This, in turn, stops the eventual production of ATP and thereby increases oxidative stress, which can lead to cellular death.[9]
So in summary, stressed cells produce nitric oxide, which binds to cytochrome c oxidase and halts the production of ATP synthase.
So How Does Red Light Therapy Restore Cellular Health?
Remember, nitric oxide competes with oxygen and binds with cytochrome c oxidase, which stops the eventual production of ATP. Well, it might be best to consider infrared light to be heroes when it comes to nitric oxide.
You see, infrared light breaks the bond between nitric oxide and cytochrome c oxidase. This allows oxygen to bind to NADH, which restores the normal pathway for hydrogen ions to produce ATP synthase.[8] So in summary, infrared light frees up cytochrome c oxidase to allow for the eventual production of ATP.
By breaking that bond and restoring the production of ATP, normal cellular metabolism can resume. And once our cells are healthy again, we’ll see the following benefits that have been proven time and time again through published clinical literature:
Increased collagen production due to stimulated fibroblasts via the release of cytokines[1]
Enhanced circulation through the formation of new capillaries[3]
Improved anti-inflammatory emissions due to increased lymph system activity[5]
Increased muscle recovery[10]
Reduced inflammation and joint pain[4]
Why Collagen is so Important for Enhanced Health?
Collagen is a long-chain amino acid and the most abundant protein in the body. It’s responsible for giving skin elasticity, hair its strength, and connective tissue its ability to hold everything in place. The collagen protein makes up 30% of the total protein in the body, and 70% of the protein in the skin![11]
While collagen is beneficial to the entire body, it's most noticeably beneficial to the skin. This is because as a person ages, the epidermis (outer layer of skin) becomes thinner and loses elasticity through a process called elastosis. As this happens, a person tends to show more signs of aging and acquires more wrinkles.
Infrared light therapy restores healthy cellular function, stimulating the production of collagen—which is why so many people have reported about the rejuvenating benefits of infrared light therapy![1]
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[1] Ferraresi C, Hamblin M, and Parizotto N. “Low-level laser (light) therapy (LLLT) on muscle tissue: performance, fatigue, and repair benefited by the power of light.” Photonics Lasers Med. 2012 November 1; 1(4): 267–286. doi:10.1515/plm-2012-0032.
[2] Al Rashoud AS, Abboud RJ, Wang W, Wigderowitz C. “Efficacy of low-level laser therapy applied at acupuncture points in knee osteoarthritis: a randomized, double-blind comparative trial.” Physiotherapy. 2014 Sep;100(3):242-8.
[3] Emília de Abreu Chaves M, Rodrigues de Araújo A, Piancastelli ACC, and Pinotti M. “Effects of low-power light therapy on wound healing: LASER x LED.” An Bras Dermatol. 2014 Jul-Aug; 89(4): 616–623.
[4] Mitchell UH, Mack GL. “Low-level laser treatment with near-infrared light increases venous nitric oxide levels acutely: a single-blind, randomized clinical trial of efficacy.” Am J Phys Med Rehabil. 2013 Feb;92(2):151-6.
[5] Michael R. Hamblin. Mechanisms and applications of the anti-inflammatory effects of photobiomodulation. AIMS Biophys. 2017; 4(3): 337–361.
[6] Raven, P. H.; Johnson, G. B.; Mason, K. A.; Losos, J. B.; Singer, S. R. How cells harvest energy. 2014 In Biology 10th ed. AP ed. pp. 122-146. New York, NY: McGraw-Hill.
[7] Reece, J. B.; Urry, L. A.; Cain, M. L.; Wasserman, S. A.; Minorsky, P. V; Jackson, R. B. Cellular respiration and fermentation. In Campbell Biology. 2011 10th ed. pp. 162-184. San Francisco, CA: Pearson.
[8] Yoshikawa, Shinya Shimada, Atsuhiro; Shinzawa-Itoh, Kyoko. 2015 Chapter 4 Respiratory Conservation of Energy with Dioxygen: Cytochrome c Oxidase. In Peter M.H. Kroneck and Martha E. Sosa Torres. Sustaining Life on Planet Earth: Metalloenzymes Mastering Dioxygen and Other Chewy Gases. Metal Ions in Life Sciences 15. Springer. Pp. 89–130.
[9] Huang, Ying-Ying; Chen, Aaron C.-H.; Carroll, James D.; Hamblin, Michael R. Biphasic dose response in low-level light therapy. 2009 Nonlinearity in Biology, Toxicology, and Medicine.
[10] Baroni BM, Rodrigues R, Freire BB, Franke Rde A, Geremia JM, Vaz MA. Effect of low-level laser therapy on muscle adaptation to knee extensor eccentric training. Eur J Appl Physiol. 2015 Mar;115(3):639-47.
[11] Di Lullo, Gloria A.; Sweeney, Shawn M.; Körkkö, Jarmo; Ala-Kokko, Leena & San Antonio, James D. (2002). Mapping the Ligand-binding Sites and Disease-associated Mutations on the Most Abundant Protein in the Human, Type I Collage.. J. Biol. Chem. 277 (6): 4223–4231.