Much confusion can occur when the public has to figure out what is the best laser technology that’s actually going to give the best results to their health problem. Because I come from a perspective of having used all three types in my practice since 2008, I will tell you that low level lasers produce the best clinical, scientifically validated, safest and long term results. Here’s why:

What does Science show?

The science literally speaks volumes on the effectiveness of Low Level Laser Therapy (LLLT, also referred to as “Cold Laser”) with over 3000 published peer reviewed studies over the last 40 years.  This intense research has enabled doctors to fine tune the best treatment dose (power), time, frequency of wavelength and pulse of wavelength.

The best laser treatment parameters produce a positive bio-stimulatory effect on multiple clinical case studies of specific conditions-like carpel tunnel and neck pain. This bio-stimulatory effect is actually a photochemical stimulation that enhances cell function called photobiomodulation. This is an non-thermal, non-sensory effect-patients don’t experience any sensation during treatment.

Class 4 received it’s FDA clearance 2 years after low level laser in 2004 based on what is termed a “Substantial Equivalent” to the level laser by showing it could create a thermal effect.  Power it has, but it did not prove a clinical enhancement of any condition or even a photobiomodulation effect with the FDA. Nor have any of it’s marketing claims to ”penetrate deeper” ever been supported by any scientific journal. In fact, higher power may negate the benefits or even cause some damage to the DNA-see below for the scientific opinion on this. To date, Class 4 laser has less than 10 studies since 2004 in peer reviewed journals.

The Optimum Laser Dose

There is a key principle in the dose of any thing that is given to create a therapeutic effect called the”Biphasic Dose Response”. This also applies to medications. This states that enough amount or energy has to cross a minimum level to create an effect, i.e., the first phase, but too much causes an overload and there is no positive effect and may be harmful. So in between the two phases is the sweet spot.

The best bio-stimulatory effect (photobiostimulation) from hundreds of scientific studies for laser therapy is low level (1-500milliwatts) with treatment times generally from 2-5 minutes. This hits the sweet spot. Higher levels can be bio-inhibitory and can negate some of the positive effects of laser and possibly cause harm by oxidative damage to DNA. With class 4 lasers (500mw-25watts) it is easy to over shoot this optimum dose amount in just a few seconds.

My Patients Speak

Class 4 laser can work to help reduce pain in many cases, I’ve seen this happen when I used it in my office, but it’s not as consistent as the low level laser, especially in the repair and regenerative aspect for long term results in my experience. After my patients started utilizing the low level laser in my practice, they never wanted to use the Class 4 again.

For a scientific reference on this dose concept:

Huang, Biphasic Dose Response in Low Level Light Therapy Dose Response, 2009, wrote “A biphasic response has been demonstrated many times in the research…it has been frequently observed where low levels of light have a much better effect on stimulating and repairing tissues than higher levels of light.”

This journal, Dose Response, is a peer review journal dedicated to researching the ideal the ideal laser dose.

For a quick 4 minute Youtube video reference on the best laser dose by a leading Harvard laser researcher, check out:

        Michael Hamblin, PhD, Principle Investigator Wellman Center for Photobiomodulation Harvard Medical School

Tiina Karu, one of the original laser researchers since the 1980‘s from Russia and a true heavyweight in the field today wrote in her book

“Ten Lectures on Basic Science of Laser Phototherapy”, wrote

“The physics claims by the Class 4 laser sales people, just are not possible.”

Turner and Hodes, also leading laser researches, wrote in the Swedish Laser Medical Society an article entilted

“Confounders and magicians” Class 4 laser claims about penetration: We urge manufactures and salesman to stick to

physical facts and scientifically proven claims and keep the hype back in the 80’s!”

What About LED Lasers?

LED lasers (light Emitting Diodes) are similar to LLL in that they are low intensity light doses and can safely deliver therapeutic bio-stim to the tissue. LEDs have been validated in hundreds of studies. However they are not a “full laser” in the sense that they do not have a coherent wavelength in the laser beam. In a true laser the particles of photons in the beam is delivered with identical wavelengths. This gives it much of its biostim effect in the tissue.

In LEDs, the incoherent light source can approximate 10-15% bio-stim of a coherent LLL and do not deliver the pulsing capability of a professional LLL. They are, however, much less expensive and can be a safe and useful home adjunct at home. Treatment times are extended to 30 to 40 minutes to be effective though.