Boosting mitochondrial function with light

The science here is pretty cool

I grew up in an era and area where “laying out” in the summer to get a tan was something that every teenager did. And yeah, my friends and I liked to lay out on the trampoline and use Crisco when baby oil wasn’t available. (I know that some of you are nodding and remembering, and the rest of you are rolling your eyes right now!)

I’ve been fascinated for the last decade or so with the role of light in various wavelengths and its effect on circadian rhythm. But it’s been more recently that I’ve started appreciating the role of light at specific wavelengths as a direct source of mitochondrial energy.

To give you a mental starting point, think about the way that plants derive energy from the sun. Chloroplasts are organelles that convert sunlight into cellular energy. Chlorophyll is the pigment in the chloroplast that absorbs light at very specific wavelengths, causing an excitation that results in the donation of an electron to the electron transport chain.

In our cells, mitochondria utilize an electron transport chain in ATP production, but the energy is generally derived from sugar or fat.

Wouldn’t it be cool, though, if we could just produce energy straight from sunlight?

It turns out that mitochondria can convert specific wavelengths of light into energy in the electron transport chain. No, it isn’t a lot of energy, and you still need food.

Let’s dig into the effects of specific wavelengths of light, the effect on the mitochondria, and a fascinating new study on how sunlight penetrates the body with long-reaching effects. Then I’ll dive into how and why this could affect healthspan and lifespan.

Light, ATP, and Mitochondria:

First, here’s a quick image showing the visual light spectrum and associated wavelengths:

ATP is the molecule used by living organisms to store energy and rapidly release it.

Our cells can make ATP in three ways:[ref][ref]

1. The conversion of glucose to pyruvate produces some ATP (in the cytosol of the cell)

2. In the mitochondria, pyruvate is used in the citric acid cycle (Krebs cycle) to produce a little more ATP

3. Also in the mitochondria, oxidative phosphorylation produces the majority of the ATP using the electron transport chain

When it comes to light converting to cellular energy, we’re focusing on the electron transport chain. Within the inner membrane of the mitochondria are “complexes” that transport electrons and eventually produce ATP, which stores energy in a chemical bond that can be used at a later time in cellular processes that need energy.

Diagram showing complexes I – IV and cytochrome c in the Electron Transport Chain on the inner membrane of mitochondria. Cytochrome c directly interacts with red/near-infrared light.

In the mitochondrial electron transport chain (pictured above) you’ll see Cyt C, which stands for cytochrome C oxidase. In complex II and complex III, you’ll find cytochrome b and cytochrome c, which are pigments that contain an iron atom and can move electrons.[ref]

Cytochrome c oxidase is the protein complex that contains cytochrome c. This is found in complex IV and is key to the production of energy from light. Additionally, the flavin proteins (FAD, FAHD) are an essential part of the electron transport chain. The flavin proteins are derived from riboflavin, a B vitamin. Flavins are also chromophores.[ref]

Wavelengths of light:

Different wavelengths can excite or be absorbed by the different complexes in mitochondria. For example, complex IV absorbs light at 620-690 nm and at 760-895 nm. Cytochrome b in complex III is activated at 980 nm (infrared). To add a little more complexity to this, light in the 400–500 nm wavelengths excites flavins, such as FAD from riboflavin.[ref][ref] There is a stimulation of cellular functions at specific wavelengths, such as between 613 and 623 nm, between 750-772 nm, and between 812-846 nm. [ref]

Near-infrared to infrared light at 1200 nm and 1700 nm also interacts with water in the cell, exciting the water and affecting temperature-gated ion channels and lipids. [ref][ref]

Creating energy (ATP) in the mitochondria directly from photons:

Measuring the increase in mitochondrial ATP from photons at specific wavelengths is difficult and, until recently, it hadn’t been measured directly.

Mitochondrial complexes work in concert, so a recent study looked at the output of total mitochondrial energy from different photobiomodulation wavelengths. In a 2024 study, researchers showed that red light (810 nm) at 0.5W for 30 seconds or 1W for 60 seconds increased mitochondrial energy output for about 2 minutes. It was a measurable increase in ATP, but it wasn’t a large amount. They estimated that the maximum ergy production from light interacting with mitochondria should be 0.2%. Compare this to plants, which typically have a photosynthetic output of 0.5-1.5%.[ref]

Sunlight and longer wavelengths:

Based on the prior studies showing that exposure to long-wavelength (infrared) light improves mitochondrial function, a new study (July 2025) shows that longer wavelengths of sunlight penetrate through the body and have beneficial effects on the body as a whole. The experiment involved adults with their backs to the sun and sensitive measurement devices on the front of their chest. The results measured the sunlight penetration at around 850 nm all the way through the body, which is pretty cool.

The same researchers then used 830–860 nm light that was aimed at the thorax for 15 minutes (compared to a sham control group). They then tested the effect on mitochondrial function in the retina of the eyes, which weren’t exposed to the light (they actually wrapped the people’s heads in aluminum foil!). The retina needs a lot of energy and contains a lot of mitochondria, and mitochondrial function significantly affects color vision. The individuals who were exposed to the 830-860 nm light had a statistically significant change in color vision discrimination, even those who had their heads wrapped in foil. This showed that there was a detectable benefit in overall energy in the body.

My takeaways from the study:

• Sunlight penetrates deep into the body, even through clothing.

• Mitochondrial benefits from red light are cell-specific, but there are also systemic benefits from light exposure at 850 nm.

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How does this apply to healthspan? Lifespan?

Most people, including me, spend a lot of time indoors and are not exposed to strong light. Energy-efficient (low-e) windows filter out the longer wavelengths starting at around 780 nm.

Clinical trials for red light therapy show many overall health benefits at specific wavelengths and specific situations. For example, a study looking at exposure to near-infrared red light found that higher intensities of light in the morning helped with overall well-being (mood, sleep, heart rate, and inflammatory markers), but the effect was only noticeable during the winter months when people weren’t getting much outdoor sun exposure.[ref]

Here’s a sampling of clinical trials on red light therapy:

• Blood sugar: A 15-minute exposure to red light (670 nm) on the back reduced blood glucose by 27% over two hours.[ref]

• Myopia (nearsightedness): Red light (three minutes, 650 nm, low level, twice daily) in children with myopia showed statistical improvement in three months. [ref][ref]

• Hair regrowth: A clinical trial in men with male pattern baldness showed that red light therapy combined with finasteride or minoxidil worked better than medication alone.[ref]

• Tooth root regeneration: Red light at 810nm, pulsed at 4.4 J for 22 seconds, was applied 13 times over the course of a year. The tooth root had new regrowth with completed closure of the apex after a year.[ref]

The argument that red light exposure (sunlight or a red light therapy device) can improve healthspan is easy to make.

However, I think the studies correlating time spent outside in the sun with mortality or age-related diseases have a lot of confounding variables. The trend of the studies does seem to show that spending time in the sun is beneficial for overall health, but it seems hard to quantify.

• A 20-year study in Italian women found that more sun exposure correlated to decreased all-cause mortality rates.[ref]

• Depression risk seems to be the lowest in people getting an average of 1.5 hours outdoors in the daylight.[ref]

• More time spent outdoors also correlates with a reduced risk of Parkinson’s.[ref]

My personal game plan:
I’m going to spend more time outside in the sun this summer and look into full-body red light therapy this winter.

• Working on a laptop outside in the sun is a pain, but the new study showing that full sun is penetrating through the body when hitting the back means putting my back to the sun and laptop in the shade is an option.

• I’m bad about eating lunch at my desk; a 20-minute lunch break outside is something that I hope to make a habit for the next couple of months.

Let me know in the comments below if you have a better game plan.