LLLT & MET: Frequently Asked Questions
Question #1: What is a Laser?
Answer: The word ‘LASER’ is an acronym for Light Amplification by Stimulated Emission of
Radiation.
A laser is a light source that is notable for its high degree of spatial and temporal coherence.
Coherence, when talking about light waves, means that the waves are ‘in phase’ with each
other; if the waves are not ‘in phase’ with each other, the light is considered incoherent.
LED Light – incoherent
Sunlight – many different colors, incoherent
LASER Light - coherent
This coherence is unattainable using other technologies. Coherent light is the foundation of
the biological basis of light therapy. When referring to spatial and temporal coherence, think
‘space’ and ‘time’. Spatial coherence is the correlation between the electric fields over
different locations across the beam profile (space) whereas temporal coherence refers to the
correlation between the electric fields at one location but different times (time).
Coherent light from a laser is light that has a single wavelength, is highly ordered and well
organized. In comparison, light from an ordinary bulb is typically un-organized. Laser light is
called coherent because it is single frequency polarized and phase correlated.
Coherent light can affect our tissue cells in a manner different from non-coherent light.
Through the process of collimating, or focusing, a specific wavelength of light, energy can
broadcast great distances.
1 Question #2: What is a Medical Laser?
There are many different types of medical lasers, but two main groups stand out:
1. High Power Lasers: used to cut, coagulate and evaporate tissues. These are often
called surgical lasers because they rely on heat to replace the scalpel.
2. Low Level Lasers: are used for the stimulation of cell function. They can also be
called bio-stimulating lasers or low-intensity lasers. Their biological effect is not
based on heat as is the case with surgical or high-powered lasers. (There are low
powered lasers that do heat tissue such as infra-red lasers.)
Question #3: How Does Medical Low Level Light Therapy (LLLT) Work?
LLLT works by stimulating a cell’s innate metabolism. The effects are bio-chemical and
therefore cannot damage living cells. LLLT lasers are therapeutic because they allow living
tissue to maintain or return to homeostasis (chemical and physiological balance) without
damaging tissue.
All light is photonic energy. The coherent light of a laser causes photochemical reactions or
photobiomodulation in the cells. The coherent laser light photons are absorbed by light
absorbing molecules (chromophores) within the cells.
The word chromophore is broken down into chromo, or ‘color’, and phore, ‘to bear or carry’.
Literally defined, it is a “carrier of color”. A chromophore acts like an antenna, or acceptor,
on the cell, mitochondrial membrane, nuclear membrane, or some intracellular protein.
Biological chromophores are pigmented (colored) substances (such as amino acids, nucleic
acids, mitochondrial enzymes, hemoglobin, melanin, serotonin, etc.) that are found throughout
living tissue, and are receptive to light of specific wavelengths or colors. The antennae of the
mitochondria can and do utilize the photons of low level laser light as a source of primary
energy.
When this absorption occurs within the cells it causes increased production of the cellular
energy molecule called ATP (adenosine triphosphate). The increase in energy allows for
normalization of cell function, pain relief, and healing.
The biological effect is significantly related to the wavelength of the light emitted by the laser
and has been demonstrated in many studies. Today, the wavelengths most commonly used
for therapeutic purposes are:
633nm 635nm 650nm 660nm 670nm 780nm 820nm 830nm 904nm 1060n
The wavelength of the LTO is 670nm +/-10.
2 Question #4: What is the Classification of a Laser?
All lasers are given a laser class; this classification is only to indicate possible damage to eyes
and has nothing to do with the possible effectiveness in treatment. There are four classes:
class 4 is the strongest and most hazardous to the eyes; classes 1, 2, 3A and 3B are less
hazardous to the eyes. The LaserTouchOne™ is a class 2 medical device.
Question #5: How Deep Into the Tissue Can a Laser Penetrate?
The photons penetrate approximately one to two inches into the skin but it’s not the depth of
penetration of the energy that causes the cells to repair and heal themselves. The photons
from the laser are at the optimal wavelength for therapeutically affecting cells that are injured
or dormant. The low level laser triggers the cells to produce enzymes; it is the cascading of
these enzymes which allow for the depth of repair that occurs and not the depth of
penetration of the actual photons.
The depth of penetration of laser light has four basic variables:
1. Light source
2. Wavelength
3. The power output
4. The technical design of the apparatus and the treatment technique used
1. LIGHT SOURCE: In living tissue, only photons of coherent light are able to pass through
optical windows in cell membranes to become accepted by chromophores (the photon
acceptors). Coherent light is only created by a laser light source, not from LED or SLD light
(superluminescent diode) sources. Coherent laser light has by far the greatest therapeutic
potential. Because the light triggers the cell’s own homeostatic mechanism, only low
intensities and doses are required for dramatic biological responses. The LTO delivers
coherent light.
2. WAVELENGTH: Every chromophore has an absorption coefficient for peak activation and
is wavelength-specific. However, each chromophore has a wide range of wavelengths in
which it will accept or donate electrons. The wavelength of the light produces energy –
the longer the wavelength, the more energy that is produced. Red light has the longest
wavelength of visible light and thus penetrates further than other colors of visible light.
Wavelengths of 620-720nm are typically better able to penetrate optical windows in
cellular membranes because their photons (energy) are not easily absorbed by healthy
tissue.
The wavelength of the LTO is 670nm +/-10.
3 3. POWER OUTPUT: The power output of a laser is measured in watts. Between 2 and 5mW
(milliwatts, or 1000th of a watt) is the average range to activate mammalian chromophores.
Power higher than 5mW may exceed the activation levels of some chromophores.
The LTO delivers .95mW of power; it has been designed around the lowest level of power
due to the synergistic effect delivered by the combination of the e-stim and LLLT, as well as
the philosophy of “less is more” as documented by many studies. One such study that
illustrates this in its results was conducted by Harvard Medical School and the University of
Massachusetts called “BIPHASIC DOSE RESPONSE IN LOW LEVEL LIGHT THERAPY”; it is
an excellent source of information whose results support the “less is more” philosophy.
Measuring the power of a laser is not enough though; there are further measurements to
calculate the distribution of the total energy over the treatment area to accurately measure
dosage. This is called the energy density (Joules/cm²).
The total photonic energy delivered into the tissue by a laser over a certain period of time
is measured in Joules. Once the Joules are calculated, the energy density can be
calculated by dividing the Joules by the beam area.
The energy density of the LTO is .6 Joules/cm².
Here is how this is calculated:
Beam Area = Pi x Radius (cm)²
= 3.14 x (.25cm)(.25cm)
= .196cm²
Energy Density = Laser Output Power (watts) x Time (seconds)
Beam area (cm²)
= .00095 Watts x 120 seconds
.196cm²
= .6 Joules/cm²
So what does this mean? For a given wavelength of light, energy density is the most
important factor in determining the tissue reaction (Baxter, 1994). Research indicates that
energy densities in the range 0.5 to 4 Joules/cm2 are most effective in triggering a
photobiological response in tissue. Again, the LTO’s energy density falls in the low range
because of the synergistic effect of the dual modalities delivered by the LTO.
4. DESIGN AND TREATMENT TECHNIQUES:
a. The design of the LTO is patented and the tip of the device is designed for optimal
myofascial release (soft tissue massage).
b. The lens of the LTO is concave, or curves inward like a spoon. This allows the
collimated (focused) light passing through it to diverge or spread.
c. The treatment technique is a combination of:
4 i. Keeping the tip flat on the skin surface
ii. Using slight pressure to the skin to allow for the greatest depth of light penetration
iii. Moving the device at a reasonable pace for the greatest coverage of cells. Keep in
mind that information travels along the nervous system at 280 miles per second, so
you can never get ahead of the LTO!
Question #6: Why Does the Laser Not Affect Healthy Cells?
Healthy cells absorb light (the transfer of energy) differently than injured or malignant tissues.
An injured cell is in a different metabolic state than a healthy cell and will accept photonic
energy more readily than healthy cells. This is the best explanation for the wide array of
therapeutic effects of the LLLT in damaged tissue and the lack of response in healthy tissue.
Example: Healthy tissue does not contain a high concentration of biologically active
chromophores (such as biogenic amine, histamine, serotonin, vasoactive intestinal peptide,
substance P) while inflamed tissue does (inflamed as in what happens to soft tissue postinjury). The four cardinal signs of inflammation are: redness, heat, pain, and swelling but these
are just the basic symptoms of a very complex series of events taking place at the cellular level
when an injury occurs. Using LLLT on inflamed tissue can shorten the timeframe of the cellular
inflammatory processes and ultimately reduce pain and severity associated with it.
“While LLLT may have no effect on a healthy, normal cell, it has profound biological and
therapeutic effects on inactive, sick or injured cells. The power of LLLT lies in the fact that
injured cells respond to irradiation, turning on or off, allowing the cell to return to or maintain
cellular homeostasis. In short, LLLT allows the cell to heal itself”. (Graham, G., Murname, J.
Light Therapy: Making the Right Choice in Laser Therapy).
Question #7: How Does Cascading Work With LLLT?
A cascade effect is a chain of events due to an act affecting a system. “The cascading effect
with LLLT is significant in LLLT. Since a considerable number of the reactive proteins
[chromophores] that respond to laser stimulation are enzymes, their impact on cellular and
tissue function is proportionate. Both in stimulation of beneficial enzymes and depression of
[harmful] enzymes, laser light action is multiplied by the cascading effect enzymes exert.”
Multiple studies show that damaged cells react to photon energy more readily than healthy
cells and while it might appear that LLLT is selectively targeting dysfunctional cells, the reality
is that these damaged cells exhibit a lower threshold to the effects of LLLT and are more easily
triggered by the photonic energy transfer responses. This results in the LLLT having
significant effects on damaged cells and tissue, while healthy or normal biological cells are
appreciably less affected.
5 Question #8: How Do Cells Communicate With One Another?
Once a cell has detected a signal, it must decide what the appropriate action is. Thus, in a
series of ordered cascades, the initial signal sets off events inside the cell, much like a domino
effect. One thing leads to another, and eventually the message reaches its appropriate
location in the cell and accomplishes its goal.
It is important to note that it is not how deep the photons penetrate the cells, but rather the
effect the photons have on helping the cells to communicate with each other. Since energy
passes through healthy cells more easily and only the injured cells react to the photonic
energy, a “signaling cascading” effect takes place. Think of the cascading as a chain reaction;
damaged cells absorb the energy from the laser and create new enzymes that allow for
normalization, healing and relief of pain. Damaged adjacent cells then, in turn, produce more
of the same bio-chemical reaction which lets them begin to normalize and relieve pain as well.
Question #9: What Is Micro-Current Electrical Therapy (MET)?
Micro-current electrical therapy or (MET) is a specific form of electrotherapy that applies
small amounts of current to the body measured in millionths of an ampere. Micro-current
applied to injured tissue normalizes the ordinary activities within the cell - it increases the
production of ATP, protein synthesis, absorption of nutrients and the elimination of wastes.
MET is able to penetrate the cell because it mimics what happens naturally in human cells and
thereby works with the body to enhance the normal physiological processes.
While the specifications listed for the LTO in the User Manual show that the maximum output
voltage is 30mA (milliAmps), the voltage that is actually delivered during treatment with the
LTO is approximately 5μA (microAmps). There are several factors that are used to calculate
this number, such as contact resistance (how well the skin conducts the current), how far the
current is traveling through the body, the pulse width, the pulse rate, and the duty cycle (the
time that the current is in active state as a fraction of total time under consideration).
Question #10: How Is Micro-Current Electrical Therapy Different than the
Therapy Delivered by A Typical TENS unit?
TENS stands for transcutaneous electrical nerve stimulation; the most common TENS devices
are designed to deliver an electrical current strong enough to fatigue the muscles and block
the pain signal to the brain. Depending on the frequency of the TENS unit, the electrical
stimulation can also trigger the body to release endorphins which are the body’s natural
painkillers and can promote a feeling of well-being. These powerful units work on the
symptoms of pain, not the source. It is a temporary solution to pain and is not designed to
reduce inflammation, reduce edema (bruising), repair at the cellular level, or promote healing.
6 The LTO is classified as a TENS device by the FDA since it delivers the same technology as a
TENS device; however, the LTO delivers a micro-current of electrical stimulation. That means
that the current strength is 1/1000th of the typical TENS’ current. Studies have shown that
micro-current delivered to the cell increases ATP production (cellular energy molecule),
thereby restoring homeostasis and facilitating the natural healing processes of the body.
Question #11: What Are Some of the Documented Effects of MET7?

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Increased ATP production/concentration inside the cell (by up to 500%)
As energy levels increase, there is enhanced transmembrane transport (removal of
metabolic wastes from the cell and enhancing nutrient distribution)
Stimulation of fibroblasts (these are cells that orchestrate tissue healing and
regeneration)
Question #12: How does Using Micro-Current Electrical Therapy Work ?
Just as LLLT provides energy to the cell, so does micro-current electrical therapy (MET or estim). When injury or disease occurs, the injured cells lose the electrical potential of the cell
membrane, as well as the ability for the mitochondria (the ‘powerhouse’ of the cell that
produces energy) to produce energy (ATP). The e-stim provides the “spark” to the cell to
wake up its electrical system.
The effectiveness of the LaserTouchOne is dependent on the combination of the spark from
the e-stim and the photonic energy (fuel) from the LLLT to stimulate the cell to normalize itself.
7 Glossary
ATP - Adenosine Triphosphate; a nucleotide found in the mitochondria of all plant and animal
cells. It is the major source of energy for cellular reactions. It is produced in the body through
the process of cell respiration and in plants through photosynthesis.
Chromophore - A chemical group that absorbs light at a specific frequency and so imparts
color to a molecule; a colored chemical compound; literally meaning Chromo-color and phoreto bear or carry
Coherent Light - Light in which the electromagnetic waves maintain a fixed and predictable
phase relationship with each other over a period of time
Fibroblasts - A type of cell that synthesizes the extracellular matrix and collagen, the structural
framework (stroma) for animal tissues, and plays a critical role in wound healing. Fibroblasts are
the most common cells of connective tissue in animals.
Inflammation - Redness, heat, pain, and swelling. A localized protective reaction of tissue to
irritation, injury, or infection, characterized by pain, redness, swelling, and sometimes loss of
function.
Laser - Acronym for Light Amplification by Stimulated Emission of Radiation
milliAmpere - A unit of current equal to one thousandth (1/1000) of an ampere
Photobiomodulation - The term that NASA and U.S. military scientists have adopted for low
level laser therapy (LLLT)
Signaling Cascades - Cellular signaling is, at the most basic level, the method by which cells
communicate with each other, and process various environmental cues to mount an
appropriate response. Of course, the survival of the organism is of utmost importance, so all
signaling events strive towards the good of the creature. This means:
1. Making compensatory physiological changes to bring the being back to baseline
(maintenance of homeostasis).
2. Or altering physiology to enable the being to better cope with the newly introduced
stressor (adaptation).
8 Sources
1. Baxter, G. D. (1994) Therapeutic Lasers: Theory and Practice. Churchill Livingstone:
Edinburgh
2. Brogemeyer, Claus Henrik. Inflammation/Pain Reduction and Healing.
3. Graham, G., & Murname, Joan. Light Therapy, Making the Right Choice.
4. Huang, Y, et al (2009) BIPHASIC DOSE RESPONSE IN LOW LEVEL LIGHT. Wellman Center
for Photomedicine, Massachusetts General Hospital, Boston, MA; Department of
Dermatology, Harvard Medical School, Boston, MA; Aesthetic and Plastic Center of Guangxi
Medical University, Nanning, P.R. China, et al.
5. Karu, T. (1999). Primary and secondary mechanisms of action of visible to near-IR radiation in
cells. Journal of Photochemistry and Photobiology, 49, 1-17.
6. Mester, E., Mester, A.E. and Mester, A. (1985) The biomedical effect of laser application.
Lasers in surgery and medicine 5, 31-39.
7. Mercola, Joseph M., et al (1995). The Basis for Microcurrent Electrical Therapy in
Conventional Medical Practice. Journal of Advancement in Medicine, 109-110.
8. Zhang, Y., Song, S. et al. (2003). cDNA microarray analysis of gene expression profiles in
human fibroblast cells irradiated with red light. Journal of Investigative Dermatology, 120(5),
849-857.
9. http://www.acuscopemyopulse.com/microcurrent_therapy.html
10. http://www.spectravet.com/LightYears.html
11. http://www.spectramedics.com/llltinfo.html
12. http://laserthera.com/how_does_lllt_work.htm
13. http://www.holachospital.com/files/theoryoflaserllt.html
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