LED Light Therapy & Power Intensity

Thousands of trials and studies conducted over the past few decades have most all researchers in agreement that photobiomodulation (PBM) therapy, also referred to as LED Light Therapy, is remarkably beneficial in helping alleviate a wide variety of common ailments and conditions — both of the body and the mind.

Despite the great deal of study that’s been dedicated to LED Light Therapy so far, there are still many questions about how treatment variables can be optimized for each and every condition. Namely, power intensity and dosage are two major variables, and it takes a great deal of trial and error to discover what combinations work best. As ongoing study continues to answer these questions, the cutting edge of LED Light Therapy and its amazing potential remains an exciting topic of discussion. So we recommend you sign up for our spam-free newsletter to hear about the latest news and discoveries!


  • Power Intensity: milliwatts per centimeter-squared (mW/cm2)
  • Irradiance: milliwatts per centimeter-squared (mW/cm2)
  • Dosage: Joules per centimeter-squared (J/cm2)
  • Milliwatt (mW): one thousandth of a watt (W)
  • Joule (J): a derived unit of energy established by the International System of Units


Higher Intensity Doesn’t Equal Better Treatment

Research so far has made one thing abundantly clear — more does not equal better when it comes to power intensity.

It makes sense, right? We’ve all heard the saying “too much of a good thing,” and light is no exception. The body can only absorb a specific amount of photons at a specific rate. Higher-than-necessary intensities provide no benefit — and they can even be bad for us.

Another popular saying fits power intensity to a T — “moderation is the key.” LED Light Therapy is a lot like your car’s gas tank — filling it to overflowing doesn’t do you any good. Our bodies just don’t work that way. Optimal healing treatments are achieved through the correct dosage and intensity delivered over time.


Biphasic Dose Response

How do we know? Biphasic Dose Response. This is when the body has two distinct responses to a stimulus, depending on the concentration delivered. The term comes from the Arndt-Schulz rule (Wikipedia contributors, 2021) which states that every stimulus either stimulates us, inhibits us, or kills us — it all depends on the concentration.

In Light Therapy, by comparing two dosages/power intensities, each delivered over specific durations, we can measure whether they benefit the patient, have little or no effect on the patient, or harm the patient.


Power Intensity Review

This 2011 review (Huang et al., 2011) gives some perfect examples. For instance, one study measured oral mucositis in hamster models, using red light therapy. The models received two different irradiances:

  • 55 mW/cm2 for 16 seconds per point
  • 155 mW/cm2 for 6 seconds per point

The models that received the lower power intensity for a longer period showed reduced severity of mucositis, while the models that received the higher intensity for a shorter duration showed no significant differences compared to controls.

Another study in the same review measured wound tensile strength in rat models, using red light at a dosage of 5J/cm2. A power intensity of 4mW/cm2 for 1,250 seconds showed positive results. But 15 mW/cm2 for 333 seconds showed no positive results.


The AAH Light Dosing

The AAH Lights were tested by a third-party professional light lab. The results and dosing table are shown on the Dosing and Power Output page.



In short, more does not equal better. Whether you receive LED Light Therapy from a medical practitioner or you self-administer in the comfort of your home, be patient. Small, consistent treatments over time will give you all the healing benefits Light Therapy has to offer.

Take a look at the amazing Aah Light to learn more about how LED Light Therapy can help you, your loved ones, and even your pets!

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Huang, Y.-Y., Sharma, S. K., Carroll, J., & Hamblin, M. R. (2011). Biphasic dose response in low level light therapy – an update. Dose-Response: A Publication of International Hormesis Society, 9(4), 602–618. https://journals.sagepub.com/doi/10.2203/dose-response.09-027.Hamblin

Wikipedia contributors. (2021, October 23). Arndt–Schulz rule. Wikipedia, The Free Encyclopedia. https://en.wikipedia.org/w/index.php?title=Arndt%E2%80%93Schulz_rule&oldid=1051428222