Infrared and red light therapy delivers light at a low energy (which is why it's also called 'low-level light therapy'). It uses red and near-infrared wavelengths to relieve pain and stiffness, reduce inflammation, and improve circulation. The light penetrates the skin and are absorbed by the body's cells, where they stimulate the production of ATP, which is the energy source for cells. The ATP powers cellular repair and cellular cleanup (autophagy), which flushes cellular waste and also reduces inflammation.