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Multiwave Locked System (MLS) laser therapy is marketed [1] as a healing and pain-relieving treatment based on simultaneous application of 808nm continuous light, and 905nm pulsed light from laser diodes.

I do not question that generic Low Light Laser Therapy can be beneficial to different ailments [2], although some do question it [3]. But the company owning the patent claims MLS to be superior. This concerns me, because cost remains a major limitation in amount&quality of medical care all around the world, and health of many people can be influenced by such claims if these are widely accepted as truth without supporting evidence.

And here are serious red flags.

A) Numerous clinical studies have shown MLS to be beneficial, but they almost always compared to control groups that got entirely no light treatment. I found a single study to compare MLS to generic LLLT with questionable significance [4]. To me, nothing seems to prove MLS is any better.

B) The name sounds like pseudo-scientific techno-babble. Sure, two pulsed lasers could be phase-locked. But how can one "lock" a series of pulses to a continuous wave? And should they call it "multiwave" when they just add light from two laser diodes?

C) The exact choice of 808nm CW laser diode and 905nm pulsed laser diode may seem to be based on some sophisticated medical knowledge. But it all may be also about cutting costs: The former are mass-produced for pumping Nd:YAG lasers (like green pointers), the latter are mass-produced for pulsed LIDAR in consumer electronics. Searching for cheap & powerful laser diodes emitting in the pass-band of haemoglobin on Ebay gives these two as the obvious choices.

Or am I missing something? Is there any supporting evidence that the patented MLS is any better than simple near-infrared light from cheap laser diodes?

References:

[1] https://www.asalaser.com/en/mlsr-laser-therapy#rest-of-world

[2] e.g. https://en.wikipedia.org/wiki/Low-level_laser_therapy and refs. therein

[3] Low level laser therapy for pain, and https://quackwatch.org/device/reports/lllt/

[4] https://pubmed.ncbi.nlm.nih.gov/28783464/ (study on 75 patients only, with marginal advantage of MLS results for treating neck pain)

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    +1. No idea how to answer this question, hence this is a comment. My impression is the entire field is pseudoscience... but none of my go-to medical sites such as SBM or Respectful Insolence seem to have covered this. Nov 15 '21 at 6:59
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    Apologies... I answered, then deleted my answer, and have restored it again, as a partial answer. It seems that LLLT has been shown conclusively to not be based on evidence. And MLT is just a marketing name for some kind of class 4 LLLT. Partial answer because perhaps it would be better to either show conclusively that they are one and the same, or find a study explicitly on MLS. Nov 15 '21 at 8:14
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    It would be rather easy to test against placebo. So they have no excuse not to. Those light frequencies are not visible except to elves and halflings. To humans the emitters seem to emit only a slight red glow, due to imperfections in the emitters spilling into the visible range. So make some placebo instruments designed to only emit a faint red glow. The fact that they do not test against placebo is all you need to hear. Nov 16 '21 at 2:10
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    I don't see any discussion in the Wikipedia article on LLLT what "low power" means in this context. I do see in the article on laser safety that a Class 4 laser WILL do something, though whether the "something" is medically beneficial requires proper study and proper laser safety. (Quick summary: When working with a Class 4 laser, do not stare at the beam, even from the side, without safety goggles.) Nov 16 '21 at 15:10
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    @CodeswithHammer I did find an article claiming that class 4 is destructive to tissue, but it was written by someone pushing LLLT. There's so much misinformation about this field. Nov 17 '21 at 6:15
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Partial answer:

Dr Harriet Hall has covered LLLT in an article on Skeptic magazine. To summarize, she writes that there is not enough evidence to support the claims.

In her article, she quoted this study as follows:

Low-level laser therapy (LLLT) has been proposed for a wide variety of uses, including wound healing, tuberculosis, and musculoskeletal conditions such as osteoarthritis, rheumatoid arthritis, fibromyalgia and carpal tunnel syndrome. There is insufficient evidence in the published, peer-reviewed scientific literature to demonstrate that LLLT is effective for these conditions or other medical conditions. Large, well-designed clinical trials are needed to demonstrate the effectiveness of LLLT for the proposed condition.

On class 4 lasers, she writes:

Manufacturers of Class 4 devices who market them for therapeutic uses claim their devices work better because they use certain specific wavelengths, rapid pulses, and proprietary innovations. They are said to penetrate deeper into tissue (6 to 9 inches). A larger treatment head compresses superficial tissues, and a larger area of the body can be treated at once. They say the photons are absorbed by melanin, hemoglobin, oxyhemoglobin, and water. Energy generated by this process is felt as a soothing warmth. Light absorption stimulates cytochrome C to produce more ATP and free nitric oxide (a vasodilator) and reactive oxygen species, growth hormone, cellular proliferation, and mobility increase. This improves blood circulation and speeds the healing process. Marketers claim all this has been documented in the lab. Maybe, but others disagree,7 saying that 90 percent of the light energy is absorbed in the first centimeter. Even if the laboratory claims are true, that doesn’t mean there are significant clinical benefits to humans in the real world outside the lab. The evidence is lacking. There is no evidence that Class 4 devices produce better clinical outcomes than Class 3B devices.

She concludes, citing this Mayo Clinic report:

The use of therapeutic lasers by veterinarians and medical doctors is not warranted by the existing scientific evidence. As the Mayo Clinic says, “the question of whether these treatments offer hope, or are merely hype and hokum, is unanswered."

I have not been able to find much on the difference between LLLT and MLT, apart from an article on Arthritisandsports.com entitled What is MLS therapy:

Unlike early-generation Class IV technology, MLS Laser Therapy has the capability to deliver controlled laser energy. This unique feature provides more accurate therapeutic dose delivery, which means consistent and repeatable results. Additionally, the MLS Laser is capable of delivering over 100x more healing energy than the most powerful devices of the previous generation. More power means shorter treatment times, less therapy needed and immediate pain relief.

They cite no sources for their claims, so as far as I can tell, MLS is a patent on top of class 4 lasers. (MLS is class 4, hence the criticism of LLLT applies to MLS.) So it's just a patent and marketing on top of LLLT, which has not been proven to be effective.

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    "healing energy"? That sounds very scientific. Nov 15 '21 at 17:55
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    @JörgWMittag well, if they are meant to deliver light energy, which somehow heals you...
    – user253751
    Nov 16 '21 at 10:41
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    @user253751 At the very least, you'll have the placebo effect happening.
    – nick012000
    Nov 16 '21 at 10:45

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