Living organisms emit weak photons used for communication and diagnostics.Biophoton emission refers to the very weak light that living cells and organisms continuously emit, typically in the visible and ultraviolet range. This light is not the result of heating (like a glowing ember) but is a byproduct of biochemical reactions, particularly those involving reactive oxygen species. The intensity is extremely low—often just a few photons per second per square centimeter—but it can be detected with sensitive photomultiplier tubes. Researchers study this emission because it may reflect the physiological state of cells, potentially serving as a non-invasive diagnostic tool.
The phenomenon was first observed in the 1920s by Alexander Gurwitsch, who called it 'mitogenetic radiation.' However, it was largely ignored until the 1970s, when Fritz-Albert Popp and others developed sensitive detectors and revived interest, coining the term 'biophotons.'
The photons arise when excited molecules, created during metabolic processes, relax back to their ground state. A major source is the oxidation of lipids and other molecules by reactive oxygen species, which produces electronically excited carbonyl groups and singlet oxygen. These excited species can emit light directly or transfer energy to other molecules (like chlorophyll in plants) that then fluoresce. The intensity and spectral composition of the emitted light correlate with the rate of metabolism and the level of oxidative stress in the tissue.
It is being explored as a non-invasive diagnostic tool for detecting oxidative stress in tissues, monitoring food freshness, and studying the effects of environmental stressors on living organisms.
A single human cell emits only about 10 to 100 photons per second, which is so faint that it would take a camera with a shutter open for years to capture a visible image.







