The human body glows—literally—but our eyes aren't sensitive enough to see it. This phenomenon is called biophoton emission or ultra-weak photon emission (UPE). It refers to the very low levels of visible light emitted by living organisms, including humans.
Biophoton emission is a scientifically measurable phenomenon, linked to biochemical reactions within cells, resulting in ultra-weak light. It requires sensitive instruments to detect, and there's no evidence that it can be seen with the naked eye, but it's typically strongest at midday as it's related to metabolism.