Why red light therapy is one of the most research-backed tools in regenerative wellness — and what it actually does inside the body Light is not passive. We tend to think of it as something we see by. Background. Ambient. A condition for visibility rather than a force in its own right. But light is energy. Specific wavelengths of light carry specific amounts of energy and biological tissue responds to that energy in precise, measurable ways. The body has been responding to li