P. acnes bacteria produce high amounts of porphyrins. When porphyrins
are exposed to specific wavelengths of blue light, they produce a
singlet oxygen molecule which destroys P. acnes bacteria. Red light
reduces inflammation by down-regulating interleukin, a pro-inflammatory
cytokine.
If you have acne LED (light emitting diode) light therapy can put you on the road to healthier skin.