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Light Emitting Diodes (LED's)

What are Light Emitting Diodes (LED’s)?  

Light Emitting Diodes (LED’s) are electronic semiconducting devices that emit light when charged with electrical voltage.  This light is not like a laser; it is diffuse in nature and cannot travel long distances.

How do LED’s work?

LED’s basically emit a single colored light in a forward direction.  The color depends on the conducting medium and the bands or wavelengths can fall in the ultraviolet, visible or infrared spectrum of energy.

What are the benefits of LED’s?

LED systems offer the ability to treat a larger area of the head or body at one time. With the correct wavelength and intensity settings for the condition, the LED phototherapy has proven to be a low-cost, effective treatment.

Basic research has shown that when red (600’s nm wavelengths) and near-infrared wavelengths (mostly 800’s nm wavelengths) are applied to cells that are compromised (hypoxic or low on oxygen), there is improved cellular respiration and function due to an increase in production of adenosine tri-phosphate (ATP) by the cell’s mitochondria. There is also improved blood circulation near the area treated, due to release of nitric oxide from parts of the mitochondria in the hypoxic cell.

What are LED’s commonly used for?

LED’s are commonly used in medical and aesthetic practices for reducing inflammation, skin rejuvenation, enhancement of wound healing, acne therapy, sports injuries, and joint pain. 

Newer areas include:

  1. Prevention of mouth sores in cancer patients undergoing chemotherapy
  2. Research with LED’s applied to the scalp, to improve thinking and memory in some brain disorders  - e.g., dementia and traumatic brain injury. 


Updated July 11, 2016
Margaret Naeser, PhD, Lac


For more information:


United Nations Headquarters (New York) presentation to the Global Health Impact Forum
James Carroll provides an overview of Photobiomodulation and low level light therapy (LLLT)

Photobiomodulation Lecture 2015 (Low Level Light Therapy)
Dr Lew Lim and leading scientists from Harvard Medical School and Boston University School of Medicine share their insights about the positive effects of low level light therapy (photobiomodulation) on the body and brain at the cellular level.

The views expressed and materials presented in this video represent the personal views of the individual speaker(s) and do not represent the opinion of the ASLMS. The ASLMS assumes no responsibility for the content of the videos made by the speaker or group of speakers.

The American Society for Laser Medicine and Surgery, Inc. is the world’s largest scientific organization dedicated to promoting research, education and high standards of clinical care in the field of medical laser applications. It provides a forum for the exchange of scientific information and participation in communicating the latest developments in laser medicine and surgery to clinicians, research investigators, government and regulatory agencies, and the public.

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