What is an “Effective Dose” of Light Therapy?

Are you exploring the effectiveness of light therapy for treating varies ailments ranging from skin conditions to chronic pain? It all begins with an effective light therapy session and light therapy dosage. The effectiveness of a light therapy session and light dose are commonly referred to as “The Therapeutic Window”. An Effective Dose is enough photons (per square centimeter of tissue being treated) to replenish and saturate the tissue to trigger photobiomodulation without heating or damaging the tissue. Too much light can result in few if any benefits. This is called the biphasic dose response. A biphasic dose response has been frequently observed where low levels of light have a much better effect on stimulating and repairing tissues than higher levels of light.

Most references and studies regard an effective dose for a single Light Therapy session to be between 3 to 60 Joules/cm² for the treatment area. A Joule is a measure of energy delivered in one second. The output of most Light Therapy Devices is measured in milliwatts (mW). 1000 mW in one second is equivalent to 1 Joule (J).

There are many different opinions out there when it comes to gauging the effectiveness of light therapy and what constitutes the right amount. The right amount can differ wildly based on a number of factors:

1. The depth of the issue: it takes different amounts of light – and often different wavelengths – to affect the skin than to penetrate bone or deep muscles. Alternately, activating acupoints can take only a few seconds.
2. The speed of delivery (how much light is coming out of your device divided by the area that is being illuminated)…faster is not always better.
3. How far from the body the light source is located. For every inch of distance you lose about 50% of the photons so have to shine your light for a longer time.
4. Whether the lymph system is already open and able to handle the increased circulation stimulated by the Photobiomodulation.
5. How healthy you are. The sicker someone is, the slower you have to proceed. Too much light in a single session could trigger a healing crisis; headaches, body aches, etc.