Light Emitting Diode-Based Therapy

William Abramovits, MD; Peter Arrazola, BA; Aditya K. Gupta, MD, PhD, FRCP(C)

In This Article


Blue light (407-420 nm) and red light (633- 660 nm) are promoted for the treatment of acne. They work by exciting high amounts of intracellular porphyrins naturally generated by Propionibacterium acnes (P. acnes). These endogenous porphyrins (mainly coproporphyrin III[1]) photosensitize the bacterium and, upon illumination, result in the formation of singlet oxygen, which combines with cell membranes to destroy the P. acnes. This process is dependent on the rate of production of excited porphyrin molecules, which is influenced by the concentration of porphyrins, the concentration of photons, the temperature, and the wavelength of the photons.[2]

Blue light and blue-red combinations have demonstrated efficacy in mild to moderate inflammatory acne, having a physical modality comparable to treatment with topical clindamycin but inferior to benzoyl peroxide plus clindamycin.[3] The viability of 24-hour in vitro P. acnes cultures was reduced by four and five orders of magnitude after two and three illuminations, respectively, with intense blue light (407-420 nm).[4] In a randomized controlled trial evaluating the use of blue light (peak at 415 nm) and mixed blue and red light (peaks at 415 and 660 nm, respectively) in the treatment of mild to moderate acne vulgaris, a mean improvement of 76% in inflammatory lesions was achieved by the combination blue-red light phototherapy after 12 weeks of daily treatment. This result was statistically superior to that achieved by blue light at Weeks 4 and 8 ( p =0.02); benzoyl peroxide at Weeks 8 ( p =0.02) and 12 ( p =0.006); and white light at all assessments ( p <0.001)[5] (See Table 1 for sources of blue and red light).