---
title: 'Boost Your Mitochondria with Red Light: Insights from Dr. Vladimir Heiskanen'
source: 'https://youtube.com/watch?v=fegThHgi9jM'
video_id: 'fegThHgi9jM'
date: 2026-08-03
duration_sec: 3268
---

# Boost Your Mitochondria with Red Light: Insights from Dr. Vladimir Heiskanen

> Source: [Boost Your Mitochondria with Red Light: Insights from Dr. Vladimir Heiskanen](https://youtube.com/watch?v=fegThHgi9jM)

## Summary

In this interview, Dr. Vladimir Heiskanen, curator of the world's largest open-access database of photobiomodulation (PBM) studies, discusses the nuanced science behind red light therapy. He explains the proposed mechanisms, the evidence for its effects on muscle growth, inflammation, and skin health, and the complexities of dosing and safety.

### Key Points

- **Introduction to the Interview** [00:02] — The host introduces Dr. Vladimir Heiskanen, who curates a database of nearly 10,000 PBM studies. The interview aims to explore the nuanced and conflicting clinical literature on red light therapy.
- **Basics of Light and Biology** [01:15] — Dr. Heiskanen explains that historically, light effects were thought to be mediated through the eyes, but now direct tissue effects are recognized. Red light and near-infrared have been tested against 300 different health issues, including skin conditions, brain, lungs, and thyroid.
- **Mechanisms: Mitochondria and ATP** [03:59] — PBM (photobiomodulation) is the scientific term. The most discussed mechanism involves mitochondria, where red light increases ATP, reactive oxygen species, and nitric oxide. The cytochrome C oxidase (CCO) theory, proposed by Dina Caro, is popular but disputed.
- **Cytochrome C Oxidase Theory** [07:09] — The CCO enzyme in the respiratory chain is considered a primary photoacceptor. Dina Caro's 1995 paper identified peak wavelengths (600-900 nm) and proposed that red light removes nitric oxide from CCO, improving energy metabolism. However, conflicting evidence exists.
- **ATP Increase is Contextual** [13:37] — While increased ATP is a common outcome, it is not universal. Effects vary by cell type, time of day, and stress levels. Some studies show no ATP increase, and in some diseases with mitochondrial overdrive, inhibiting metabolism may be beneficial.
- **Muscle Growth Evidence** [17:18] — Four clinical trials on leg extension training: two in young people showed positive results, but two in elderly participants showed no benefit over placebo. Evidence is stronger for young people, but limited to leg muscles and short durations.
- **Inflammation Reduction** [19:30] — A 2006 Russian study showed reduced systemic inflammatory markers after irradiating the lower back. However, other studies (e.g., diabetic neuropathy, fibromyalgia) found no effect on systemic cytokines. Results are mixed.
- **Systemic Effects** [22:51] — PBM can have remote effects: irradiating the abdomen protected the brain in a Parkinson's mouse model, and leg irradiation protected the heart in pigs. These are called 'remote effects' or 'remote tissue conditioning'.
- **Skin and Collagen** [25:29] — Red light improves fibroblast function, increases collagen synthesis, reduces collagen breakdown, and protects against UV damage. Human studies show increased skin elasticity and reduced wrinkles, though not all studies are positive.
- **Dosing Variables** [30:04] — Key variables include wavelength, power, duration, frequency, and energy density. Common wavelengths are 660 and 830 nm, but many others are used. Positive result rates vary by wavelength, with 1070 nm showing 80% positive studies.
- **Calculating Dose** [34:06] — Dose is often expressed as energy density (J/cm²) or total energy (J). There is no consensus on which is more important. Doses vary widely (100-fold differences) between studies, making it hard to determine an ideal dose.
- **Guessing Doses** [39:21] — Dr. Heiskanen guesses: ~10 J/cm² for superficial tissues, ~100 J/cm² for deep tissues; total energy ~100 J for superficial, ~1000 J for deep. He emphasizes these are rough guesses.
- **Negative Impacts and Safety** [43:41] — Too much red light can be harmful, especially to sensitive tissues like testes and eyes. Some studies report increased tumor growth (about 20% of cancer studies). However, actual harm is rare; PBM is surprisingly safe compared to drugs.
- **Skin Color and Light Absorption** [48:12] — Darker skin absorbs more visible red light due to melanin, reducing light available to mitochondria. Near-infrared is less affected. There is no established method for dose adjustment based on skin type, and studies rarely report skin color.
- **Open Access Database** [51:11] — Dr. Heiskanen's database is open access for 10 years, containing ~9,600 studies, with ~1,000 new studies per year. Access via bit.ly/pbm.

### Conclusion

Red light therapy is a promising but complex field with many open questions. While evidence supports benefits for skin and some conditions, dosing remains a guessing game, and effects are highly contextual. The science is evolving, with thousands of new studies each year.

## Transcript

we're doing something a bit different. The red light therapy market is full of bold claims and easy answers. Here we are talking to Dr. Vladimir Heiskinan, the man who curates the world's largest open access database of nearly 10,000
PBM studies. As you will hear, the actual clinical literature is incredibly nuanced, full of conflicting data, and highly contextual. If you are looking for a simple magic bullet, this interview might surprise you. But if you
want to understand the true state of the science, including where PBM fails, the hidden risks, and why standard dosing is bit of a guessing game, you will find this a great resource. So, let's get into it.
into it. [music] Heiskenan, a researcher at the University of Helsinki and the curator of the world's most comprehensive open access database of photobiomodulation
spanning over 5,000 clinical and preclinical studies. So Dr. Heiskinan, welcome to Modern Healthspan and thank you so much for joining us today. >> Thank you. >> Thank you. So Dr. Heiskinan, can we
start off by understanding the basics of how light impacts human biology? So when how light impacts human biology? So when I shine a red light onto my skin, how does that affect us? uh yeah in the past like if we think uh
uh yeah in the past like if we think uh 10 or 15 years ago I think most of the people in the field of medicine and biology were thinking that most of the biology were thinking that most of the effects from light come through the eyes
effects from light come through the eyes and um usually they were talking about blue light how it affects circadian rhythms but uh now that the red that therapy has become more popular. We are seeing like there are a lot of reports
seeing like there are a lot of reports showing also direct effects of light on the tissues and there have been numerous reports showing a lot of different biological
showing a lot of different biological effects from red light and um the most common ones have been improvements of cellular energy metabolism and some anti-inflammatory effects and
and some anti-inflammatory effects and also improved tissue function. And so also improved tissue function. And so far, red light and near infrared have been tested against 300 different health issues.
300 different health issues. Um for example if we consider the skin it's being tested about some inflammatory conditions for example acne and redness of the skin and dermatitis from the radiation
therapy. It's been tested against sensitive skin, diabetic dermopathy, and like all of all kinds of different conditions. And of
kinds of different conditions. And of course, red light therapy. Even though we often hear about the effects on the skin and maybe muscles, it's been tested skin and maybe muscles, it's been tested for like uh all kind of all kinds of
for like uh all kind of all kinds of body parts. It's there are is research suggesting potential benefits on the brain and lungs and
some endocrine glands such as thyroid gland gland and um how the effect happens and um how the effect happens um when we talk about PBM effects
uh okay when I say PBM I'm referring to the scientific name of the red light the scientific name of the red light therapy. Lay people often talk about red therapy. Lay people often talk about red light therapy but scientists talk about
modulation that is abbreviated as PBM. And um uh when we shine the red light on the
cells uh there is an agreement that the cells contain a lot of different compounds, proteins, enzymes that are able to proteins, enzymes that are able to absorb light. And uh while there is some
absorb light. And uh while there is some dispute about the most important photo acceptors, those compounds that absorb light and those compounds that absorb light and bring some biological effects. Uh
bring some biological effects. Uh most of the talk is centered about the mitochondria. Mitochondria are small organels inside the cells. And often the biology text books show that
you have like one or two mitochondria within the cell, but actually they can have hundreds and even thousands of mitochondria in a in one cell.
mitochondria in a in one cell. And uh often after the red light irradiation we see changes like increased ATP levels, uh slightly increased reactive oxygen species and increased
nitric oxide levels. oxide levels. And uh there is some for example British um research showing that if you have like [snorts] complete like animals like
like [snorts] complete like animals like fruit flies that are small enough to be kind of [snorts] thoroughly I how do you pronounce it like completely irradiated by red light. You can see even increase on in the full body ATP levels. the ATP
on in the full body ATP levels. the ATP is the most well-known product of those is the most well-known product of those mitochondria organels in the cells
like what exactly is happening and the mechanisms are they can be divided to like primary and secondary or thirdary effects based on the
kind of order what happens first and what is happening after that and which what is happening after that and which effects happen like more slowly.
>> Can we can you talk about what is the the general agree what is the the most likely way that the extra ATP is generated? How does the red light impact the mitochondria so that they can generate
more ATP? Much [clears throat] of the discussion is centered about the discussion is centered about the respiratory chain of the mitochondria. respiratory chain of the mitochondria. And there is this enzyme cytochrome C
And there is this enzyme cytochrome C oxidase that is often abbreviated as CCO oxidase that is often abbreviated as CCO and um the CCO works as an important and um the CCO works as an important enzyme in the respiratory chain. it um
enzyme in the respiratory chain. it um is doing some like redux reactions within the mitochondria. And uh back in the 95 a Russian or
actually actually I think Estonian or Russian researcher Daro Russian researcher Daro uh published a very highly uh published a very highly very popular paper
very popular paper about uh cytochrome C oxidase as the main photo acceptor for red light therapy. Uh she showed that uh the red therapy. Uh she showed that uh the red light uh effects happen
uh especially with some specific wavelengths that are within the range of 600 and 900 nanometers. And um she showed that there were like a
couple of peak wavelengths that showed the most strong effects from red light. And then uh she put a put out a long paper
then uh she put a put out a long paper where she wrote that those specific wavelengths [snorts] probably represent some specific parts of the cytochrome c oxidase. And since then when you read red light
And since then when you read red light therapy papers they most often site this Dina Caro theory of red light therapy mechanism. theory of red light therapy mechanism. However um if you read only papers about
red light therapy mechanisms there clearly is a lot of dispute about there clearly is a lot of dispute about the this mechanism. There are several
scientists that disagree about this cytochrome C oxidase theory or at least they provide some experimental evidence that shows either like porer of replica
that shows either like porer of replica replicating some of the results. For example, there are some American researchers who tried to um investigate the effects of red light on isolated cytochrome oxidase and
on isolated cytochrome oxidase and didn't they were not able to didn't they were not able to uh show effects that were kind of uh show effects that were kind of um predicted by this tinaros theory and
Um then we have some experimental results of um that show that even the cells that do not contain cytochrome C oxidase they not contain cytochrome C oxidase they are also affected by red light. And then
are also affected by red light. And then there are like all kinds of pieces of evidence showing that some other mechanisms may also be in play at least mechanisms may also be in play at least with some specific wavelengths.
For example, uh light can also release nitric oxide uh light can also release nitric oxide from various stores in the body. There are like numerous different compounds that store nitric oxide.
Red light can also uh produce nitric oxide within the cytochrome c oxidase. Um and yeah, one of the part of this Dina Caro's theory was that um or this main most popular theory of
red light mechanism was that stressed and inflamed cells can produce nitric and inflamed cells can produce nitric oxide and this can inhibit the energy
oxide and this can inhibit the energy metabolism metabolism in the um mitochondria in the way that nitric oxide binds finds in the way that nitric oxide binds finds this cytochrome C oxidase
this cytochrome C oxidase and um according to the theory when you get red light the red light removes the nitric oxide and after that mitochondria starts functioning more efficiently and you get more energy. This is called the
you get more energy. This is called the nitric oxide um dissociation nitric oxide um dissociation photo dissociation theory or nitric oxide inhibition relief hypothesis
hypothesis but uh whether it's actually true there is conflicting like research some groups have not been
like research some groups have not been able to show this effect of nitric oxide able to show this effect of nitric oxide release from cytochrome c oxidase by red release from cytochrome c oxidase by red light. So I think nowadays we are in a
situation where there are a lot of uncertainties about the mechanisms. We have like some popular theories and some less popular theories. And if you
think it from the scientific perspective, I don't think we have enough certainty to kind of conclude if one of them is kind of conclude if one of them is completely true or not. We probably need
a little bit more basic research of the mechanisms. So, but I think earlier what you you said that if you shine red light on the cells, you see an increase in ATP. So, is that generally agreed? We may not
is that generally agreed? We may not agree how it happens, but in general, people can replicate that red light produces more energy, ATP being energy. >> At least it's a result that has been shown many times, but not always. So uh
BBM seems to have quite contextual effects that differ between like cell types. Uh maybe the part of the day because
there is some research showing red light effects in the morning but not in the afternoon or maybe even some results showing red light effects in the nighttime but not daytime. So uh many contextual factors
daytime. So uh many contextual factors may change the effects of red light. may change the effects of red light. Some researchers have written that PBM may work better in stressed cells compared to healthy cells. So if the
cell is already functioning well, we are maybe not expecting such a big effect maybe not expecting such a big effect from red light. So I think we have seen
the increase in ATP many times and there have been even like studies showing like have been even like studies showing like measuring the effect quite like very measuring the effect quite like very very soon after the irradiation like
maybe a couple of minutes after the red light irradiation and then also like a couple of hours later. So later. So uh yeah, I think
uh yeah, I think there are is so much research showing the increased ATP as an outcome. So it's very likely. But also because we have those negative results, we probably have to conclude
results, we probably have to conclude that the ATP increased ATP is not the result in all of the situations. There can be situations where red light doesn't necessarily increase ATP levels.
increase ATP levels. Uh biology is often kind of a complex thing. For example, it's very common to say that in many diseases we have mitochondrial dysfunction that is inhibiting the
energy metabolism and lowering ATP levels. But there are also diseases levels. But there are also diseases where mitochondria go overdrive. where mitochondria go overdrive. So there is too much energy production
and in those situations it makes most sense to maybe inhibit the metabolism. to maybe inhibit the metabolism. Uh I think in red light therapy there
Uh I think in red light therapy there have been also some not very often but I think I've seen a few individual results where the outcome was less ATP where the outcome was less ATP and as far as I remember I think it was
and as far as I remember I think it was associated with some benefits. So yeah associated with some benefits. So yeah maybe in most of the situations more ATP maybe in most of the situations more ATP is what happens but it's nuanced.
is what happens but it's nuanced. >> Okay. So but mostly we get more ATP. So if we >> if we if we take a step back so the red light seems to increase the function of the mitochondria because they are the
organels that produce most of the ATP. So if we look more broadly at what are the physiological effects of having more ATP or of the of the red light? I mean and in particular I mean do we see that it helps with
muscle growth or muscle repair? >> Uh good question. uh for m muscle >> Uh good question. uh for m muscle growth. I tried to look into the studies growth. I tried to look into the studies and I found like four clinical trials
and I found like four clinical trials and two of those uh were in young people and two of those uh were in young people and that they measured the effect of uh and that they measured the effect of uh leg extension training
uh with red light or near infrared light on the muscle growth. and they saw on the muscle growth. and they saw positive results. Then there was one study in older women uh that had quite similar
uh that had quite similar methods but it did not show benefit over methods but it did not show benefit over placebo and then there was one study in placebo and then there was one study in elderly men and it also did not show
benefit over placebo. So uh my maybe interpretation is that the uh my maybe interpretation is that the evidence is stronger for young people evidence is stronger for young people and in elderly people. We have not yet
demonstrated increased muscle growth from red light therapy. from red light therapy. And uh all of the research only studies And uh all of the research only studies leg extension training. So we don't have
data on other muscles yet and uh of course the studies often have quite limited time range like two months or something like that.
like two months or something like that. So there is still more research that we So there is still more research that we could do in the field of PBM research. could do in the field of PBM research. So one other thing that uh PBM is meant
So one other thing that uh PBM is meant to do is to reduce inflammation, reduce systemic inflammation. So is there evidence for that? Um and I I guess is it systemic or is it local? I mean do you need to put the red light on
the inflamed area or does it reduce inflammation systemically? Uh the first study that I read about this topic maybe 12 years ago was a
this topic maybe 12 years ago was a Russian study that was published in 2006 and it investigated the effects of broadband light probably I think they were using the bioptron device.
were using the bioptron device. Um they irradiated the lower back area of the humans and then they measured the inflammation markers in the blood and they showed greatly decreased
greatly decreased markers of inflammation in the blood markers of inflammation in the blood and but then um after that I've been and but then um after that I've been trying to find more data that
either supports or doesn't support the effects of red light on systemic inflammation. Um there are some studies of PBMUs for
conditions that cause systemic inflammation. For example, corona virus or pneumonia and those studies that try tested PBM on
these uh uh infections that cause systemic uh infections that cause systemic um inflammation. they have been demonstrating less inflam inflammatory markers and
less inflam inflammatory markers and also improved healing. But then uh for example there was one study using red light therapy for diabetic neuropathy light therapy for diabetic neuropathy and they also happened to measure the
systemic inflammatory cytoines and they did not show any effect. And then there is one study that used high doses of near infrared to bring some
hyperothermia. So warm like he healing of the body to So warm like he healing of the body to treat fibromyalgia pain. So I think it treat fibromyalgia pain. So I think it showed benefits for the pain but not no
improvement in the inflammatory cytoines in blood. So I think the results on systemic inflammation is slightly mixed. I think it probably
helps in some people and with some parameters but not like all in all situations we don't do not always see improvement in systemic
see improvement in systemic inflammation. So I'm not really uh sure what exactly you need to get the systemic inflammation benefits and um you asked about the
whether the red light therapy effects are local or if there are systemic effects also. I think there have been published many papers that demonstrate
some kinds of uh effects that are systemic. So when you irradiate like one body part, you can see benefits elsewhere.
Um I think some of the quite well-known examples are from Australia where there examples are from Australia where there is a research group um testing a red light for the animal model of Parkinson's disease. They
demonstrated that I think they demonstrated if you irradiate the demonstrated if you irradiate the abdominal part of the mice you still get abdominal part of the mice you still get protective effect in the brain. Then um
also in Israel they had pigs and they induced an the they had pigs and they induced an the animal model of the heart attack and uh
they got some heart protection by irradiating the legs. irradiating the legs. So that was another demonstration of kind of systemic effect of photobiomodulation.
photobiomodulation. Some um researchers call it also remote Some um researchers call it also remote effect or remote tissue conditioning. effect or remote tissue conditioning. And in America, I think we have some uh
animal research showing that you can protect the eyes from the harms that come with the diabetes uh even if the head is covered. So if
the even if the eyes don't receive direct light exposure and then we have some data showing that and then we have some data showing that if you irradiate one hand you may see
increased blood flow in the other hand as well. So there certainly are hints that the red light therapy can have some systemic effects. systemic effects. We just um we don't have kind of a
We just um we don't have kind of a theory that explains everything and why what is happening in which situation but we just have a lot of like random we just have a lot of like random examples suggesting systemic effects.
use for red light is for skinincare. Then you you kind of mentioned that before and it kind of make and it makes sense because it's easy to irradiate the skin and it doesn't have to get too deep to
be able to help. So do we know what's going on there? I mean how does light going on there? I mean how does light impact like the fibroblasts and does it impact like the fibroblasts and does it increase collagen development?
increase collagen development? >> Yes, it's a good question. Um there are a lot of cell culture studies with fibroblasts and I think most of those have been conducted by researchers who are mostly interested in wound healing
are mostly interested in wound healing and not skin care. But the fibroblasts and not skin care. But the fibroblasts are very relevant in what happens in on are very relevant in what happens in on the skin level. And um red light seems
the skin level. And um red light seems to alter or improve fibroblast function to alter or improve fibroblast function in many situations. For example, if we have some stressors bringing like increased oxidative stress. Um red light
seems to improve the viability of these cells in if you have wounds. It seems to cells in if you have wounds. It seems to improve fibroblast migration that can improve fibroblast migration that can help the process of wound healing. It
help the process of wound healing. It can modulate the inflammatory processes. can modulate the inflammatory processes. Then there are studies that where you Then there are studies that where you uh expose the cells or the skin of the
uh expose the cells or the skin of the mice to ultraviolet radiation and the red light seems to bring like protection to activate DNA repair mechanisms.
uh it seems to decrease the levels of the enzymes that break do this breakdown of collagen. I think there is also evidence for
increased collagen synthesis. So it seems to bring all kinds of So it seems to bring all kinds of effects on the in the fibroblast and the effects on the in the fibroblast and the skin and uh it has been also repeated in
like in humans. We have some research of the the um mostly middleage people who have some photoagging or age related
age related changes in their skin usually facial skin and red light therapy has shown increased elasticity of skin and decrease in wrinkles. So I
think the evidence at least points to the direction of benefits. the direction of benefits. Uh it's not 100% conclusive. There are some studies where you we didn't see any
you we didn't see any uh benefits from red light to like wrinkles and human skin health. But let's say that the randomized trials
with the best quality, I think they show benefits. So I think uh it's more likely benefits. So I think uh it's more likely that they have benefits than they do not that they have benefits than they do not uh the like red light therapies and
yeah and the studies also they do not have massive sample sizes and often the duration of the studies is like one month or 3 months. So of course in ideal
month or 3 months. So of course in ideal world we would have large studies that world we would have large studies that uh like have the duration of 3 years or something. When you study like the effects of cholesterol drugs, the trials
effects of cholesterol drugs, the trials can be four years long or the or five years. But in red light therapy research, we often have like one or two research, we often have like one or two or three months long studies.
>> Yeah. Well, that's because you can't charge people lots of money for the red light. So we we talked about the impact that So we we talked about the impact that red light has on mitochondria and skin
and collagen but kind of getting practical I mean about dosing I mean how so I mean there are a lot of variables that we need to consider right there's the the wavelength and there's the duration of
time the time of day you mentioned as well uh and also the power uh so what what are the most important variables and what kind of values for
wavelengths and power should people be looking for or were used in the trials? Um yeah, if you look at the trials, you can see like a lot of variation in the
can see like a lot of variation in the parameters. Like if you look like trials parameters. Like if you look like trials made in Japan, they like they very very made in Japan, they like they very very often use the 830 nanometers and there
often use the 830 nanometers and there can be like some how do you say favorite can be like some how do you say favorite wavelengths for some countries and so but uh the two most common wavelengths are 660 and 830 nmters.
But then uh the following wavelengths are also relatively common. Uh 630, 633, 635, 650,
780, 808, uh 810, 850, 94, 940, 980, 94, 940, 980, 1,64, and 172. These are like the most
common wavelengths in the PBM research. But you can also see many other wavelengths. And um two years ago I made a quick And um two years ago I made a quick estimate of like uh how different
wavelengths were associated with positive results. I think that with uh visible red light approximately 60% of the clinical
studies showed positive results with near infrared it was around 50% near infrared it was around 50% except that uh with 810 nanometers it
except that uh with 810 nanometers it was around 60% and with around 1,070 was around 60% and with around 1,070 nanometers it was around 80%. % uh but of course different wavelengths have been tested for very different
indications and those parameters can be very different. very different. We cannot really explain the positive or We cannot really explain the positive or null results only by wavelengths.
But yeah, what made me interested was like the results for 170 were quite promising because 80% of the studies showed positive results.
showed positive results. But yeah, this was just one relevant parameter wavelength. Then we also have to consider like power output, power to consider like power output, power density, energy, energy, density,
density, energy, energy, density, uh the duration of the irradiation, the beam size and also the frequency of the sessions because there have been like some studies where you could see some benefit
studies where you could see some benefit from like one irradiation per week but no benefit from three ear radiations per week. So sometimes when you alter like week. So sometimes when you alter like one parameter you can see better or
one parameter you can see better or worse results. also need to we need to be concerned about like the the total energy absorbed
which would I guess be like the the energy the watts times the time. I mean is there from the from the trials is there any uh any way to come up with a what would
uh any way to come up with a what would be a reasonable optimal dose? I mean how would you calculate such a dose? It it actually so would the dose be in jewels? So that would be like the total power output or would it be based on some
other metric? Yeah, I think the two most like um how do you say the most important metrics are probably energy density and
metrics are probably energy density and total energy absorbed and I think there are differences between the researchers like some researchers may find they may focus mostly on the total energy and they may say that if you treat muscles
they may say that if you treat muscles you can should maybe use 1,000 jewels But then other researchers may talk mostly about energy density that is the unit is jewles per square cm and yeah so I think there is no kind of
uh general agreement like um of these two like which is which one is more important is more important um and uh Yeah, there are like
if you look at the research you can see so huge variation also in the doses like you may have like one single treatment indication for example
let's say the osteoarthritis of the knees and I think you can see even like knees and I think you can see even like 100fold differences between two research
groups like some groups use low doses and some groups use high doses and sometimes you can see some benefits from both. So it can be very confusing when
you want to make some conclusions on the ideal dose because sometimes I think we ideal dose because sometimes I think we see quite good results from low doses and sometimes very good results from high doses but sometimes
high doses but sometimes only one of those brings benefits. So only one of those brings benefits. So yeah, I think it's not uh simple to yeah, I think it's not uh simple to anybody, not even the experts.
And um but of course we can make some kinds of generalized uh guesses. kinds of generalized uh guesses. Um for uh but first uh if we consider the research uh the humans are very big animals and
when you use the light it doesn't penetrate very deep. uh if we cons consider that a lot of research has been done with cell monollayers like a single done with cell monollayers like a single layer of cells it's very very thin and
in the cell level it's probably easier to make some kind of estimates of the to make some kind of estimates of the ideal dose but if we want to irradiate muscles uh and we have this let's say 1,000
uh and we have this let's say 1,000 jewels of the energy absorb absorbed uh most of that 1,00 juwles is absorbed by the skin and the muscle is not by the skin and the muscle is not receiving that much light
receiving that much light after the skin level absorption. So after the skin level absorption. So uh the we cannot make uh conclusions uh the we cannot make uh conclusions from cell culture studies that apply to
humans and we cannot make conclusions from mice or [snorts] rats because they also have thinner skin than human at least I think so. I don't know the exact
least I think so. I don't know the exact thickness of rat skin or human skin. So uh yeah and uh if we want to treat skin that is very superficial
uh part of the body of course we probably don't need that much light probably don't need that much light because uh the most of the light reaches because uh the most of the light reaches the skin and uh also I think if you want
to treat like thyroid gland it's probably not very deep but then if you probably not very deep but then if you want to treat some very deep tissues, want to treat some very deep tissues, then it seems like believable that you
should increase the dose a little bit. And what are the good like um doses? um doses? I'm not very good at qu guessing but if
we think in the terms of energy density I would guess maybe something like 10 I would guess maybe something like 10 jewles per square cm for superficial jewles per square cm for superficial tissues and maybe 100 jewles per square
tissues and maybe 100 jewles per square cm for deeper tissues. So maybe 10 times more. And in the terms of total energy absorbed, I would maybe aim for 100 jewel for
superficial tissues and 1,000 jewel superficial tissues and 1,000 jewel jewels for deep tissues, but I'm not confident about these values. It's just a guess,
a guess, >> right? Okay. And jewels. So mostly uh red light devices are rated in in watts per centime squared. So to get from watts to jewels, you multiply by the time in seconds or
time in seconds or >> uh yeah. Yeah, you uh I think the most common unit for power density is like millw per cime and
power density is like millw per cime and millwatts is like 1,000 parts of the millwatts is like 1,000 parts of the watts and uh then you need to multiply it with the number of seconds. So for example, if the power density is 100 mw
example, if the power density is 100 mw per square cm and you multiply it with 300 seconds, the energy density is going to be 30 jewles per square cm. And if
you want to calculate total energy absorbed, you need to kind of absorbed, you need to kind of uh know the power output of the device.
uh know the power output of the device. Um that is measured in watts and you need to multiply the number of watts with this number of seconds,
more difficult to kind of know the actual power output and sometimes a part of the light output may kind of not be uh if for example if
may kind of not be uh if for example if you are far away from the device maybe some of the light goes to elsewhere not your body and so on. Yes, I think some of the light lights
Yes, I think some of the light lights are rated based on you know centime um watts per c millwatts per centime squared at 5 in or something like that. So so that they include some distance in the in the
include some distance in the in the >> like a very very helpful thing because uh if you don't have any light measurement device it's not very easy to know how much light you are receiving because
um yeah often people like talk about this uh inverse square law of the power this uh inverse square law of the power density that says that if you double the distance then the power density decreases four-fold. But it only kind of
decreases four-fold. But it only kind of [snorts] um it only applies if the light [snorts] um it only applies if the light source is like infinitely small. But if source is like infinitely small. But if you have a large panel, if you double
the distance, the decrease in the power density maybe it can be very small. So it depends on the size of the light source.
So when the manufacturer um gives you the information that okay um gives you the information that okay you have 100 mattes per square from 5 in you have 100 mattes per square from 5 in and uh 50 m per square from the distance
and uh 50 m per square from the distance of 12 in. That's like kind of a good of 12 in. That's like kind of a good thing and informative information. thing and informative information. >> Right. So just one thing the
is there has there been any u negative impact shown from red light? So especially having too much red light because you have said that um like some
of the dosing is like a 100 times difference between the two. Uh do we see any contraindications from or or do do we see any negative impact from having too much red light? Um yeah, I think we should kind of think
Um yeah, I think we should kind of think in from the perspective that too much of anything can be harmful and there can be like some tissues can that can be more
sensitive than other tissues. For example, I think maybe some glands. example, I think maybe some glands. Um, for example, testes in males may be
Um, for example, testes in males may be kind of sensitive to stressors and kind of sensitive to stressors and eyes can be sensitive. eyes can be sensitive. So, in those situations,
So, in those situations, um, yeah, it's possible that red light um, yeah, it's possible that red light could bring some harm. Um and there are could bring some harm. Um and there are some like harms that you can find from
the scientific literature as well. I guess the one that guess the one that um I can remember the best is that while um I can remember the best is that while PBM has been studied as a like a therapy
for tumor growth and most of the results seem either no harm from red light or seem either no harm from red light or even benefit. maybe one in five studies like 20% of the studies [snorts] also report increased to more growth from red
report increased to more growth from red light. So there are certainly like some light. So there are certainly like some specific situations where red light can bring some even unexpected harms. Um and we probably do not know
harms. Um and we probably do not know like in which situations red light would protect somebody from tumor growth and what are the situations where [snorts] it can be harmful. I think one of the things that make it
make this more complicated that is that um when we think about cancer we often think it of it like as one disease or 10 diseases
but there can be like huge differences between different forms of cancer and their metabolism and how they function. their metabolism and how they function. So it's a very complicated field and uh
there are some singular like reports of eye like some usually reversible um harms to the eyes from red light
um harms to the eyes from red light therapy. But there are also many studies that use relatively high doses of red light to the eyes and they report like slight benefits. So I think it's not very common to see harms. I think there
very common to see harms. I think there was like some animal research suggesting was like some animal research suggesting maybe some testicular harm in animals maybe some testicular harm in animals from red light but maybe the dose was
from red light but maybe the dose was quite high but um keeping these kind of negative [clears throat] examples in mind I think I've gone through thousands of red light studies and the
and the incidence of this negative like results are showing actual harm. They are like very very rare. I think if we compare
red light therapy to most drugs or I think it's surprisingly think it's surprisingly safe after all and if people use relatively modest like
uh energies then in most situations I think actual then in most situations I think actual harm is quite unlikely. >> Right. So one question on skin. So if you have
darker skin, does skin color make like the amount of melanin in the skin, does this make a difference to the amount of light that red light that gets absorbed? >> Yes. I think uh especially for visible red light, darker skin, the melanin in
red light, darker skin, the melanin in the skin absorbs it and then less light the skin absorbs it and then less light will be available for the mitochondria. will be available for the mitochondria. And uh I think all the same applies to
And uh I think all the same applies to um near infrared also but with a smaller magnitude. But um I'm not sure about the exact But um I'm not sure about the exact values like of how much you should use
like more light. If you have darker skin and of course there can be some situations where if you have darker skin maybe the light could bring a little bit more thermic effect on the skin like if you have very
high power density. But of course most people are not using very high power densities. So it's not relevant. But at the moment I am not aware of any actual
method for dose adjustment according to skin type. I'm not even sure like I'm skin type. I'm not even sure like I'm not sure if any calculators exist. [snorts] I mean, in the studies, do you see many
that specifically talk about different skin types or skin colors that they ran the studies on? >> Uh, no, I don't see it very often. I
have seen it sometimes, but it's not something that is regularly reported, >> right? >> It should be. Yeah. I think when we want
to conduct studies, it's important to have conduct studies, it's important to have high do you say replicability of the studies. So um it should be reported like what is the skin color of
participants and uh what is the time of the day when PBM is uh used and like the the day when PBM is uh used and like the more data we have the easier it's to
more data we have the easier it's to make a replication study where that is kind of identical to the original study. And uh of [snorts] course many researchers report the basic parameters quite well but I think we in ideal world
we would have like even much more information about the exact protocols information about the exact protocols and that would be very good for the for the research. >> Yes. So Dr. Genanon, you keep this
>> Yes. So Dr. Genanon, you keep this database of red light papers. Is that >> yes. >> Yes. And and can people access it? Is it >> Yes. And and can people access it? Is it available? Is it is it open access?
>> Yeah, it's been open access for 10 years. Anybody can use it in any way they want. But of course, people cannot edit my version of the uh database. So
if they want to edit it, they have to download it and use it from their own download it and use it from their own their own copy of it. And uh the I usually give the short link to people that is like www.bitly.com/pbm
the link. So if you can put it somewhere. >> Absolutely. Yeah, I can put it in the description so people can can find the database. Yeah. >> Yeah. And yeah, the database it's pretty
>> Yeah. And yeah, the database it's pretty huge project because it almost has 10,000 studies about red light therapy. I think the number is probably something I think the number is probably something like 9,000 and maybe 600.
It's and now we are seeing like 1,000 new studies now we are seeing like 1,000 new studies per year. So it's a lot of work to keep per year. So it's a lot of work to keep it up to date. Maybe in the future
artificial intelligence could assist a little bit, but maybe not yet. it and thank you so much for uh doing that work and keeping it up to date.
That's that's very helpful. Um it's interesting that there's so much interest in uh red light therapy and yet I mean just talking with you there seems to be so many open questions still. We we really don't seem to know the
answers. But I guess that's biology is like that. Yeah, biology is very very complex and much more complex than what like people who do not like do research
like people who do not like do research think like I think yeah I've I read a think like I think yeah I've I read a lot of medical research about like all lot of medical research about like all kinds of subjects I have like maybe 300
keywords and I'm getting like daily email alerts of and yeah it's complex But I'm very happy that we have this large research community and every year
we get like this 1,000 red light therapy studies and over long time periods we studies and over long time periods we will know much more than we know today. [snorts] >> Okay, Dr. Heisken, thank you so much for
joining us today. It's been great talking with you. talking with you. >> Thank you. Thank you for the invitation. >> Thank you. Thank you for the invitation. [music]