LED-emitted photons must be absorbed by a molecular chromophore or photo acceptor. Light, at appropriate doses and wavelengths, is absorbed by chromophores such as porphyrins, flavins, and other light-absorbing entities within the mitochondria and cell membranes of cells.

The enzyme responsible for the critical steps of cell respiration, especially cytochrome oxidase governing the last reaction in this process. Two chemical quirks are exploited: carbon monoxide (CO) that can block respiration by binding to cytochrome oxidase in place of oxygen, and a flash of light that can displace it, allowing oxygen to bind again.

In turn, in LED-exposed cells like fibroblasts increased ATP production, modulation of reactive oxygen species (such as singlet oxygen species), reduction and prevention of apoptosis, stimulation of angiogenesis, increase of blood flow, and induction of transcription factors are observed.