Biophotons are extremely faint light emissions produced by nearly all living cells, from bacteria and plants to human skin and organs. They are not visible to the naked eye. The intensity is roughly a billion times weaker than daylight, with mitochondria emitting somewhere between 1 and 1,000 photons per square centimeter per second, spanning wavelengths from ultraviolet through the visible spectrum and into the near-infrared.1Radiation Medicine and Protection. Biophoton signaling in mediation of cell-to-cell communication and radiation-induced bystander effects The phenomenon is real, measurable with sensitive photon-counting equipment, and rooted in well-understood biochemistry. What remains far more contested is what these photons actually do, whether they carry meaningful biological information or are simply metabolic exhaust fumes that happen to glow.
Where the Light Comes From
The primary source of biophotons is reactive oxygen species, the chemically aggressive molecules produced as byproducts of normal metabolism. Your mitochondria churn through oxygen to generate energy, and in the process, some electrons go astray. These stray electrons create reactive molecules like superoxide, hydrogen peroxide, and hydroxyl radicals.2PubMed Central. Biophoton emission induced by heat shock When these reactive species attack fats, proteins, and other biomolecules in the cell, they kick off chain reactions of oxidation. Some of those reactions push molecules into an “excited” energy state, and when the molecules relax back down, they release the excess energy as photons.
Two types of excited molecules do most of the emitting. One is triplet-state carbonyls, which form when oxidized fats break down. The other is singlet oxygen, a particularly reactive form of oxygen that glows when it transitions back to its ground state.3PubMed Central. Triplet Excited Carbonyls and Singlet Oxygen Formation During Oxidative Radical Reaction in Skin Together, these two sources account for the bulk of ultra-weak photon emission. The process is essentially the same chemistry that causes cooking oil to go rancid, except it is happening at a microscopic scale inside living tissue, and the light it produces is vanishingly faint.
Because biophotons originate from oxidative reactions, anything that ramps up oxidative stress in a cell also ramps up photon emission. Heat shock, radiation exposure, chemical toxins, and even emotional stress can push the signal higher. The connection between oxidative metabolism and light emission is one of the best-established findings in this field, supported by decades of work showing that scavenging reactive oxygen species with antioxidants reliably dampens the glow.4Journal of Photochemistry and Photobiology B: Biology. Role of reactive oxygen species in ultra-weak photon emission in biological systems
What the Light Looks Like
Biophotons are not a single color. Spectral analysis of human skin emissions reveals a range spanning roughly 450 to 750 nanometers, covering blue through deep red and into the near-infrared. The dominant emission sits in the 570 to 670 nanometer range, with a primary peak around 600 to 650 nanometers, which falls in the orange-red part of the visible spectrum.5PubMed. Polychromatic spectral pattern analysis of ultra-weak photon emissions from a human body Palm skin, which has been studied extensively because it is relatively easy to measure, shows emission peaks at 630 to 670 nanometers with a secondary peak in the green range around 520 to 580 nanometers.6PubMed Central. Imaging of Ultraweak Spontaneous Photon Emission from Human Body Displaying Diurnal Rhythm
These emissions fluctuate throughout the day. The same imaging study found that cheek emission roughly doubled between morning and late afternoon, peaking at about 3,000 photons per second per square centimeter around 4 p.m. The face and upper body tend to emit more than the limbs, and individual variation is substantial. One study mapping photon emission across 20 subjects found that total emission could vary almost fivefold between people, though the proportional contribution from each body region stayed remarkably consistent from person to person.7ScienceDirect. Anatomic characterization of human ultra-weak photon emission with a moveable photomultiplier and CCD imaging Your face always glows more than your hands, even if your overall intensity is higher or lower than someone else’s.
A Brief History of a Strange Idea
The notion that living things emit light dates back a century. In 1923, the Russian biologist Alexander Gurwitsch reported that onion root tips could stimulate cell division in neighboring roots, even when separated by a quartz window that blocked chemical signals but transmitted ultraviolet light. He called it “mitogenetic radiation” and proposed that cells communicate through faint UV emissions.8PubMed Central. Revisiting the mitogenetic effect of ultra-weak photon emission The idea was deeply controversial. Many labs tried and failed to replicate the results, and by mid-century most biologists had dismissed it as an artifact.
Interest revived in the 1970s when the German biophysicist Fritz-Albert Popp developed sensitive photomultiplier equipment capable of detecting single photons. Popp confirmed that cells do emit measurable light, coined the term “biophotons,” and went further, arguing that the emissions showed an unusual degree of coherence, meaning the light waves were organized rather than random. He proposed that DNA acts as the primary source and that biophotons serve as an information carrier within and between cells.9PubMed. Biophoton emission. New evidence for coherence and DNA as source Popp’s work attracted attention but also skepticism, partly because his claims about coherence went well beyond what the measurements could definitively prove, and partly because the “biophoton biofield” concept brushed up against alternative medicine territory. Recent work has revisited his framework, proposing the term “photonic biofield” as a way to describe the spatial and temporal patterns of these emissions.10PubMed. Coherent photonic biofields: Revisiting Fritz-Albert Popp’s hypothesis Whether this amounts to a genuinely useful concept or a rebranding of speculative ideas remains an open question in the field.
Skin, Sun, and Oxidative Damage
One of the more practical lines of biophoton research involves skin. When you expose skin to ultraviolet A radiation or even visible light, the oxidative stress generated in skin biomolecules triggers a burst of photon emission. UVA exposure produces significantly more emission than visible light alone.11PubMed. Ultraweak photon emission induced by visible light and ultraviolet A radiation via photoactivated skin chromophores: in vivo charge coupled device imaging The light that comes back out is not reflected UV. It is new light, generated when UV energy is absorbed by fatty acids, elastin, melanin precursors, and phospholipids in the skin, which then undergo photosensitization reactions and re-emit at characteristic wavelengths.12PubMed Central. Ultraviolet A irradiation induces ultraweak photon emission with characteristic spectral patterns from biomolecules present in human skin
This matters because the intensity of UV-induced biophoton emission appears to track with actual skin damage. Researchers have found that the amount of long-lasting emission in the minutes after UV exposure correlates with the degree of redness that develops 24 hours later. When a vitamin E derivative known to prevent UV-induced redness was applied, it suppressed both the biophoton signal and the lipid peroxidation that causes the damage.13PubMed. Exploitation of long-lasting ultraweak photon emission to estimate skin photodamage after ultraviolet exposure The implication is that biophoton imaging could serve as a real-time, noninvasive way to assess how much oxidative damage UV exposure is actually causing, long before visible sunburn appears.
Can Biophotons Detect Disease?
Because biophoton emission reflects oxidative metabolism and stress, researchers have explored whether abnormal emission patterns could flag disease states. The most intriguing results come from cancer research. Cancer cells, which have notoriously disrupted metabolism, appear to emit light with a different spectral signature than healthy cells. In one study, non-cancerous cells emitted proportionally more light at longer wavelengths (near-infrared and red), with intensity increasing as the filter wavelength moved toward the red end. Cancer cells showed the opposite pattern, emitting proportionally more photons at shorter, near-UV wavelengths, with counts decreasing as wavelength increased.14PubMed Central. Biophotonic markers of malignancy: Discriminating cancers using wavelength-specific biophotons If this spectral reversal holds up across larger studies, it could become a way to distinguish cancerous from healthy tissue without biopsies.
Cardiovascular disease has also attracted attention. Mitochondrial dysfunction plays a central role in heart disease, and since biophoton emission is tied to mitochondrial oxidative metabolism, researchers have proposed that measuring emission patterns could serve as a marker for cardiovascular risk.15PubMed Central. Detecting presence of cardiovascular disease through mitochondria respiration as depicted through biophotonic emission More broadly, the link between biophoton detection and a cell’s redox state has been framed as a potential clinical tool, one that could complement existing oxidative-stress biomarkers with a noninvasive optical readout.16PubMed Central. Biophoton detection and low-intensity light therapy: a potential clinical partnership None of these applications has reached routine clinical use. The signals are extraordinarily faint, require expensive photon-counting equipment and complete darkness, and the biological variability between individuals is large enough to make interpretation tricky.
Plants Glow Too, and It Is Already Useful
Biophoton research has arguably made more practical headway in plant science than in human medicine. Plants under stress emit dramatically more light than healthy ones, sometimes a thousand to ten thousand times more.17Scientific Reports. Modelling biophoton emission kinetics based on the initial intensity value in Helianthus annuus plants exposed to different types of stress Drought, salinity, extreme temperature, heavy metals, and pathogen attack all drive up emission. In the model plant Arabidopsis, biophoton imaging has been used to assess the extent of oxidative damage from various stressors, acting as a signature of the plant’s physiological state and general health.18PubMed Central. Application of ultra-weak photon emission imaging in plant stress assessment
The pattern of the emission decay also carries information. When stressed plants are briefly illuminated and then measured in darkness, the rate at which their “delayed luminescence” signal fades follows different kinetic patterns depending on the type of stress, biotic versus abiotic, drought versus infection. This means biophoton analysis could potentially distinguish not just that a crop is stressed but what kind of stress it is experiencing, which matters for deciding whether to irrigate, apply fungicide, or take other action. The equipment is still specialized, but the signal-to-noise ratio in plants is far more favorable than in humans, simply because stressed plant tissue emits so much more light.
Do Cells Actually Talk With Light?
This is where the science gets genuinely speculative. The idea that biophotons serve as a signaling system between cells, rather than just being metabolic waste light, has been circulating since Gurwitsch’s original onion experiments. Modern researchers have found some suggestive evidence. When cells are exposed to ionizing radiation, they emit UV biophotons. Neighboring cells that receive those photons, even through an optical window that blocks chemical signals, go on to release exosomes, tiny membrane-bound packages of signaling molecules, that can then modulate cell death and mitochondrial function in a third population of cells.19PubMed Central. Exosomes are released by bystander cells exposed to radiation-induced biophoton signals: Reconciling the mechanisms mediating the bystander effect This chain of events, radiation → biophoton → exosome → biological response in a distant cell, is one of the more concrete demonstrations that biophotons can trigger downstream biological effects.
The broader claim, that biophotons serve as a general-purpose communication channel carrying coherent information throughout the body, remains far less established. Some researchers argue that DNA concentrates and emits biophotons in a coherent manner, essentially acting like a biological laser that coordinates cellular activity.20PubMed Central. Speculations about Bystander and Biophotons The word “speculations” in that paper’s title is telling. The coherence measurements are technically difficult, and whether the degree of coherence observed is sufficient to carry meaningful information over biological distances is disputed. It is one thing to show that photons are emitted and that nearby cells respond. It is another to claim this constitutes a signaling system comparable to chemical neurotransmitters or hormones.
Biophotons and the Brain
Perhaps the most provocative corner of biophoton research involves the nervous system. Nerve fibers, particularly the myelinated axons that carry signals through the brain and spinal cord, have physical properties that could theoretically act as optical waveguides, essentially fiber-optic cables for biophotons. Electromagnetic modeling of myelinated axons suggests they could transmit photons with low attenuation and low dispersion within a narrow bandwidth, with the operating wavelength depending on the axon’s diameter and the number of myelin layers.21PubMed. Electromagnetic modeling and simulation of the biophoton propagation in myelinated axon waveguide The idea is elegant: the same biological structures that carry electrical signals could simultaneously carry optical ones.
Recent work has added a tantalizing correlation. When researchers measured ultra-weak photon emissions from the heads of human participants while simultaneously recording brain activity with EEG, they found that biophoton emission from the scalp correlated with alpha-band brain waves over the occipital lobes when participants had their eyes closed.22iScience. Human ultraweak photon emissions correlate with brain activity and functional rhythms Alpha waves are the dominant rhythm during relaxed wakefulness with closed eyes, generated in the visual cortex at the back of the head. The fact that photon emission from the same region tracked with this specific brain rhythm is suggestive, though the study cannot establish whether the photons play any functional role or are simply a byproduct of the metabolic activity underlying those brain waves. The correlation was specific to the occipital region and disappeared at temporal measurement sites, which argues against it being a nonspecific artifact, but it is still a long way from proving that neurons use light to communicate.
Emotional State and Photon Emission
One study attempted to measure whether emotional states affect biophoton output. Volunteers were guided through anger self-stimulation and relaxation states while their photon emission was recorded. The intensity during anger was about 0.5 to 1 percent higher than during relaxation, corresponding to roughly 10 additional photon counts. The difference was not uniform across the entire emission range; anger appeared to contribute most at higher intensities rather than shifting the baseline evenly upward.23Microchemical Journal. Increment of spontaneous human biophoton emission caused by anger emotional states. Proof of concept The effect, if real, is tiny. The study’s subtitle, “proof of concept,” signals how preliminary this is. A one-percent intensity shift is well within the range where measurement noise, skin temperature changes, and subtle muscle tension could confound results. Still, it aligns with the general principle that anything increasing metabolic rate or oxidative stress should nudge emission upward.
Why the Field Moves Slowly
Biophoton research sits in an awkward position. The basic phenomenon is well-established: cells produce reactive oxygen species, those species generate excited molecules, and excited molecules emit photons. Nobody seriously disputes this. The chemistry is textbook. But the signal is so faint that measuring it requires photomultiplier tubes or cooled CCD cameras operating in complete darkness, often with long exposure times. The equipment is expensive, the measurements are sensitive to temperature and ambient light contamination, and biological variability between subjects is large. These practical barriers have kept the field small and have made replication of more exotic claims difficult.
The field also has a credibility problem that it has partly brought upon itself. Because biophotons sound mystical, “your body emits light,” the concept has been enthusiastically adopted by alternative medicine practitioners, energy healers, and supplement marketers who claim that biophotons prove the existence of auras, qi, or other vitalistic forces. Serious researchers studying ultra-weak photon emission frequently find their work cited alongside pseudoscience, which discourages mainstream funding and collaboration. The gap between “cells produce trace amounts of light as a byproduct of oxidation” and “your body’s light field carries the blueprint of health” is enormous, but the two claims get blurred in popular accounts.
That said, the diagnostic applications in both plant science and potentially in human medicine are grounded in straightforward biochemistry. Measuring how much light a cell or tissue emits is, at bottom, a way of measuring how much oxidative chemistry is happening. Whether the photons themselves carry information or are simply useful indicators of the underlying chemistry, either way, they could eventually serve as a noninvasive window into metabolic health. The research community is still working out which of these possibilities is worth pursuing, and a fair reading of the evidence suggests the indicator role is far better supported than the communication role.