LED LIGHT Therapy

NASA originally began experimenting with red light therapy on plant growth in space and then to help heal wounds in astronauts. Low-level light therapy is usually applied via light-emitting diodes (LEDs) as red or blue light. Blue light with wavelengths of 390–600 nm reaching superficial layers and red and infra-red light with wavelengths of 600–1100 nm penetrate the deeper layers.

Blue light therapy penetrates approximately 0.3 mm into the skin. Cutibacterium acnes (formerly Propionibacterium acnes), the main bacterium involved in acne, produces large amounts of porphyrins, which have a peak absorption at 415 nm. Blue light excites these porphyrins, leading to the production of reactive oxygen species and the subsequent destruction of the bacteria. Blue light also has anti-inflammatory effects.

Red light (600–650 nm) and infra-red light (560-1100 nm) activate porphyrins with less intensity than blue light. However, they penetrate the skin 1–2 mm deeper than blue light. Red and infra-red LED treatments reduce inflammation, inhibit keratinization (scaliness), and reduce skin barrier damage. Red light therapy also reduces the activity of acne by accelerating wound healing and reducing the inflammatory response.