You Are Glowing Right Now — Your Eyes Just Can’t See It

Right now, as you are reading this, your body is producing light.

Not metaphorically. Not as an infrared heat signature. Actual photons of visible light are constantly leaving your skin.

The only problem is that the glow is far too weak for your eyes to detect.

Scientists call this phenomenon ultraweak photon emission, or UPE. It has been observed in many living organisms, including plants, animals and humans. With extremely sensitive cameras, researchers can even photograph the faint light coming from the human body.

Where does the light come from?

The glow appears to be a side effect of ordinary metabolism.

Inside our cells, oxygen is constantly being used to extract energy from nutrients. During these chemical reactions, highly reactive molecules known as reactive oxygen species can be produced.

When these molecules interact with proteins and fats, some molecules temporarily enter an excited energetic state.

As they return to a lower-energy state, they can release part of that energy as a photon.

In other words, some of the chemistry keeping you alive occasionally leaks energy as light.

This is very different from the infrared radiation associated with body temperature. Ultraweak photon emission can extend into wavelengths that are technically visible to humans — there simply aren't enough photons for us to notice them.

Your glow changes during the day

One particularly fascinating experiment photographed volunteers using an extremely sensitive CCD camera in complete darkness.

The researchers found that photon emission was not constant.

It followed a daily rhythm.

Emission was weakest in the morning, increased during the day and reached its highest levels in the afternoon. Interestingly, the face appeared to emit more photons than several other measured areas of the body.

The pattern roughly followed changes in metabolic activity, suggesting that our invisible glow may reflect what is happening inside our cells.

Could we use it to measure health?

Possibly — but this is where things become much more experimental.

Because oxidative processes influence photon emission, researchers have investigated whether UPE could eventually provide a completely non-invasive way of monitoring metabolic or physiological changes.

Imagine measuring aspects of oxidative stress simply by counting the tiny number of photons escaping from the skin.

The idea is intriguing, but the technology is nowhere near a replacement for conventional medical tests. Human photon emission is extremely weak and can be affected by many internal and environmental factors.

There are still many unanswered questions about exactly what the signal tells us.

So yes, humans really do glow

Just not enough for anyone to see.

Every second, countless chemical reactions are taking place inside your body. A tiny fraction of their energy escapes as photons, producing a constantly changing optical trace of cellular metabolism.

The strange part isn't that living organisms emit light.

The strange part is that we've been glowing our entire lives without noticing it.