Mitochondria, Cellular Energy & Near-Infrared Light

Mitochondria are often described as the “energy factories” of cells. The comparison is useful, but mitochondrial biology is more complex than simply turning energy production up or down.

One area of photobiomodulation (PBM) research explores how red and near-infrared light may interact with mitochondria and other cellular signaling systems. This research offers a framework for understanding what may happen after light reaches biological tissue, while also highlighting how much depends on wavelength, dose, delivery method and the experimental model being studied.

Mitochondria and ATP

Cells require a continuous supply of usable energy to maintain normal activity. Much of that energy is transferred through adenosine triphosphate, commonly known as ATP.

Inside mitochondria, nutrients and oxygen contribute to a sequence of reactions called the electron transport chain. Cytochrome c oxidase, or CCO, is the final enzyme in this chain. It helps transfer electrons to oxygen and contributes to the proton gradient used to produce ATP.

Neurons have ongoing energy requirements for maintaining membrane potentials, transmitting signals and supporting communication between cells. For this reason, mitochondrial activity has become an important area of brain-energy research.

ATP, however, should not be treated as a simple measure of how alert, focused or rested someone feels. Cellular energy metabolism is one part of a much larger biological system.

How Near-Infrared Light Is Studied

Photobiomodulation research typically examines red or near-infrared light delivered at defined wavelengths, intensities and exposure times.

Near-infrared wavelengths are of particular interest because they interact with tissue differently from visible light. Even so, light is progressively absorbed and scattered as it passes through skin, bone, blood and other tissue. The amount reaching an underlying target varies with anatomy, placement, contact, wavelength and device geometry.

Researchers therefore distinguish between:

Light emitted by a device
Light delivered at the tissue surface
Light that travels through overlying tissue
Light that reaches a biological target
The cellular response, if any, produced at that target

These are related but not interchangeable measurements. A wavelength being widely studied does not, by itself, establish a specific biological or wellness outcome.

CCO and the Mitochondrial Hypothesis

One of the most widely discussed PBM hypotheses proposes that photons interact with CCO or other light-sensitive cellular components, sometimes called photoacceptors.

Laboratory and preclinical studies using particular light parameters have reported changes involving mitochondrial membrane potential, oxygen consumption, ATP-related activity and redox signaling.[1,2] These observations contributed to the mitochondria-centered explanation of photobiomodulation.

A simplified version of the proposed sequence is:

Light exposure → interaction with cellular photoacceptors → changes in mitochondrial or redox signaling → downstream cellular responses

This remains a developing scientific model rather than a universally established pathway. CCO may be one part of the explanation, but researchers are also investigating ion channels, calcium signaling, structured water and other photophysical mechanisms.[3]

The response may also depend on the condition of the cell. Healthy cells and metabolically stressed cells may not react to the same light exposure in the same way. Findings from isolated cells or animal models therefore cannot automatically be applied to the human brain, an individual user or a particular consumer device.

Nitric Oxide and Redox Signaling

Nitric oxide, or NO, is a naturally occurring signaling molecule involved in mitochondrial activity, blood-vessel regulation and cellular communication.

NO can interact with CCO and temporarily influence mitochondrial respiration. One proposed PBM mechanism suggests that certain light exposures may affect the interaction between NO and CCO. Other studies examine whether light can influence nitric oxide availability through additional pathways.[4]

Researchers also study redox signaling—the balance of oxidation and reduction reactions within cells. Small, temporary changes in reactive oxygen species can participate in normal signaling. Excessive or prolonged oxidative changes, however, may have very different effects.

This is why photobiomodulation should not be described simply as “adding energy” to cells. The research involves a network of mitochondrial, redox, nitric oxide, calcium and gene-signaling processes whose responses may vary across models and parameters.

Why Wavelength and Dose Matter

PBM cannot be defined by wavelength alone. Its light-delivery profile is shaped by several connected variables:

Wavelength
Irradiance
Exposure time
Radiant exposure
Illuminated area
Continuous or pulsed delivery
Pulse frequency and duty cycle
Distance and contact with tissue
Tissue depth and individual anatomy

Research frequently describes a biphasic dose response. In simplified terms, a lower and a higher exposure may not produce the same response, and increasing intensity or session time does not necessarily increase the desired biological effect.[5]

This is one reason results from studies using different devices or protocols cannot be treated as directly interchangeable. Reviews of PBM parameters have found substantial variation across wavelengths, irradiances, exposure times and target tissues, with no single protocol suitable for every research context.[6]

Pulsing is another delivery variable. Both continuous and pulsed light are being studied, but current research does not establish one pulse frequency as universally optimal for mitochondrial function.

Why 810nm Is Used in PBM Research

810nm falls within the near-infrared range commonly investigated in photobiomodulation. It has been used in laboratory, preclinical and human studies because of its optical characteristics and its place within the broader near-infrared research window.

That does not mean 810nm is automatically absorbed most effectively in every tissue or produces a predictable response in every person. Biological exposure still depends on light intensity, duration, delivery geometry, tissue properties and the distance between the light source and the intended target.

Brainlume uses 810nm near-infrared light delivered through six head-worn light modules during a standard 20-minute session. These specifications describe how the device delivers light at the surface. They do not directly measure the amount of light reaching deeper tissue or establish that a particular change in ATP, CCO activity or mitochondrial function occurs in every user.

Brainlume also offers 10Hz and 40Hz operating modes for different daily routines. These frequencies are product delivery settings; they should not be interpreted as proof of a specific cellular response.

A Research Framework, Not a “Brain Restart”

Mitochondrial research provides a useful scientific framework for exploring how near-infrared light may interact with biological systems. It does not support describing light as literally restarting, repairing or reprogramming the brain.

The current evidence suggests that:

Mitochondria may participate in cellular responses to certain red and near-infrared light exposures.
CCO is an important proposed photoacceptor, but it may not be the only mechanism involved.
ATP, nitric oxide, calcium and redox signaling are interconnected.
Biological responses depend on multiple light and tissue parameters.
Findings from one experimental model cannot automatically be transferred to another device, tissue or person.

Responsible science requires separating what has been observed, what has been proposed and what remains to be tested. Brainlume’s design is informed by the broader PBM research landscape while remaining focused on simple, repeatable daily wellness routines.

References

de Freitas LF, Hamblin MR. “Proposed Mechanisms of Photobiomodulation or Low-Level Light Therapy.” IEEE Journal of Selected Topics in Quantum Electronics. 2016;22(3):7000417. https://doi.org/10.1109/JSTQE.2016.2561201
Hamblin MR. “Mechanisms and Mitochondrial Redox Signaling in Photobiomodulation.” Photochemistry and Photobiology. 2018;94(2):199–212. https://doi.org/10.1111/php.12864
Liebert A, et al. “Photophysical Mechanisms of Photobiomodulation Therapy as Precision Medicine.” Biomedicines. 2023;11(2):237. https://doi.org/10.3390/biomedicines11020237
Kashiwagi S, et al. “Photobiomodulation and Nitric Oxide Signaling.” Nitric Oxide. 2023;130:58–68. https://doi.org/10.1016/j.niox.2022.11.005
Huang YY, Sharma SK, Carroll J, Hamblin MR. “Biphasic Dose Response in Low-Level Light Therapy—An Update.” Dose-Response. 2011;9(4):602–618. https://doi.org/10.2203/dose-response.11-009.Hamblin
Zein R, Selting W, Hamblin MR. “Review of Light Parameters and Photobiomodulation Efficacy: Dive into Complexity.” Journal of Biomedical Optics. 2018;23(12):120901. https://doi.org/10.1117/1.JBO.23.12.120901

Disclaimer: This article is provided for general educational purposes. The research discussed includes laboratory, preclinical and human studies conducted with different light sources, devices and parameters. It should not be interpreted as evidence that Brainlume produces the same biological responses. Brainlume is a general wellness device and is not intended to diagnose, treat, cure or prevent any disease or medical condition.