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Photobiomodulation - Low Level Light Therapy (LLLT)

Photobiomodulation - Low Level Light Therapy - Biological reaction to light is nothing new. We normally experience this through our eyes which are obviously photosensitive – our vision is based upon light hitting our retinas and creating a chemical reaction that allows us to see. We experience this with vitamin D synthesis in our skin – due to sunlight creating biochemical reactions. We experience this with suntans – due to the light of the sun stimulating our melanocytes to proliferate and give us “brown” skin. Light reacts chemically with other things as well. Hydrogen peroxide is stored in dark bottles so that light can’t get in and initiate a chemical degradation. Light can photo-chemically affect all things – eventually – one way or another.

Low level laser therapy does not induce heating in tissue like surgical or aesthetic lasers. It’s all in the photochemical reactions of certain wavelengths of light with our cell membranes, cellular organelles and enzymes. Compromised cells respond better than healthy cells to photochemical reactions so that brief treatments with low level light on damaged tissue can induce a complex chain of physiological reactions to enhance wound healing and tissue regeneration, reduce acute inflammation, treat chronic pain and even to make our skin look younger and more vibrant.

Red light accelerates hair growth. It has also been shown to biochemically melt fat cells. Low level infrared light has been shown to significantly enhance the recuperation of stroke victims by shining a low level laser that you can’t even see or feel on top of your head for a few minutes at a time. Sounds like magic doesn’t it? – well, it is. It’s light and it does seem to have magical properties. The science of this “magic” has become increasingly better explained in recent years and it is apparent that this is a valid therapy for many conditions. In spite of the scientific validity of LLLT there are still many commercial claims for devices that are not well supported and some are in fact just plain incredulous. The message to take from this though is to not throw out the baby with the bathwater when confronted with some of the fringe claims of LLLT. It has substantial merit as a valid therapy.

It has been called many names over the years including biostimulation, LLLT, cold laser therapy, and more recently photobiomodulation. Low level lasers (mostly diode lasers in the 10-200 milliwatt range) have been the primary instruments but there are also non-laser light emitting diodes (LED’s) and other light sources that are used.

In the U.S. one sees these low level red, blue, yellow and infrared lights used in sports medicine clinics as part of the physical therapy to enhance healing of joint and soft tissue injuries such as arthritis treatment, carpal tunnel syndrome or athletic sprains and injuries. It has been used prior to radiation therapy in breast cancer to prevent the inflammatory dermatitis that is frequently associated with this. In MediSpas these devices are used for periodic treatments to enhance skin rejuvenation.

The devices are employed as one of the therapy options in pain clinics to treat chronic pain, including shingles pain. Some units are even being sold to the home market for general treatment of muscular and joint “aches and pains”. It’s used for things like low back or cervical neck pain, and is good to consider for use in hard to manage problems like fibromyalgia.

Its major use however has been outside of the United States, and outside of FDA restrictions, where it has been a long standing therapy for wound healing – especially chronic wounds such as decubitus or diabetic ulcers that are otherwise hard to heal. In research, LLLT appears to enhance nerve regeneration in spinal cord injuries.

There is a related type of low level laser use that has been widely publicized, but does not appear to work by the same “photobiomodulation” mechanisms. That’s the “stop smoking” and “weight loss” laser clinics that appear all over the United States. Aside from some strong testimonial support from treated clients, there does not currently appear to be much scientific evidence establishing the mechanisms of action of this type of laser therapy. That doesn’t mean that it won’t eventually be found to be valid, but the evidence is just not there yet and it should not be confused with conventional LLLT. In “stop smoking” or “weight loss” the light is directed at certain anatomical acupuncture points that correspond to nerve networks. Regular LLLT for tissue regeneration or chronic pain treatment does not require this. If the laser therapy proves to have an actual effect to help people stop smoking then it is probably an acupuncture type of therapy that simply uses low level lasers instead of needles to induce these changes, and it would then beg the question of whether the needles wouldn’t then be more effective to begin with (although many people would prefer the light over penetrating needles).


The potential applications of low level laser therapy are very widespread, and too broad to list in much detail in this introductory article. You should now have a better idea of what LLLT is however, and differentiate it from related low power laser uses like stop smoking. When you are ready to research it more you’ll find prolific material that has been generated over the years with Russia having probably the most experience, but also Europe, South America and the Middle East.

(Updated June 3, 2010)

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