#326 - AMA #65： Red light therapy： promising applications, mixed evidence, and impact on health and aging
Episode Stats
Words per Minute
159.47545
Summary
In this episode, we cover red light therapy, a topic we get asked about all the time. In fact, my wife asks me about it all of the time, so it was clear that it was time for an AMA. In this conversation, we lay the foundation for what Red Light Therapy is and why there is such an emphasis on it, and then break down the various forms of Red Light therapy and their various treatments into whether or not I think they are beneficial.
Transcript
00:00:00.000
Hey everyone, welcome to a sneak peek, ask me anything or AMA episode of the drive podcast.
00:00:15.820
I'm your host, Peter Atiyah. At the end of this short episode, I'll explain how you can access
00:00:20.280
the AMA episodes in full, along with a ton of other membership benefits we've created,
00:00:24.900
or you can learn more now by going to peteratiyahmd.com forward slash subscribe.
00:00:30.600
So without further delay, here's today's sneak peek of the ask me anything episode.
00:00:38.900
Welcome to ask me anything episode 65. I'm once again joined by my co-host Nick Stenson. In today's
00:00:45.540
episode, we cover red light therapy as a topic we get asked about all the time. In fact, my wife
00:00:51.200
asks me about it all the time. So it was clear that it was time for an AMA. In this conversation,
00:00:57.180
we lay the foundation for what red light therapy is and why there is such an emphasis on it. We
00:01:02.300
then break down the various forms of red light therapy and their various treatments into whether
00:01:06.400
or not I think they are beneficial. In other words, we go through each application and review the data
00:01:11.660
for them. So these include red light therapy for aging in general, skin health and acne, wound healing,
00:01:17.460
hair loss, eye health, exercise performance and recovery, metabolic health, general weight loss,
00:01:24.200
spot fat loss, inflammation, injury rehab, and menstrual cramps for women. So in other words,
00:01:30.600
we go through each of these and do a detailed analysis of the literature. We close this conversation
00:01:37.080
by summarizing my overall takeaways for each use case and explain via a summary table that we created
00:01:43.360
that breaks down everything you might want to know to understand this. If you're a subscriber and you
00:01:48.100
want to watch the full video of this podcast, you can find it on the show notes page. If you're not a
00:01:53.200
subscriber, you can watch a sneak peek of the video on our YouTube page. So without further delay,
00:01:58.820
I hope you enjoy AMA number 65. Peter, welcome to another AMA. How are you doing?
00:02:09.460
Good. Thanks for having me back. Anytime. Anytime. So today's AMA, we are going to focus on a single
00:02:15.960
topic, which is red light therapy. This is something we get asked about a lot, not only questions from
00:02:21.760
the website and subscribers, but I know through your patients as well. And so we compiled all these
00:02:27.000
questions and through this conversation, hopefully going to cover what red light therapy is, how it can
00:02:32.520
work, deep dive into some various claims out there around red light therapy. This can include
00:02:38.700
potential effect on skin health, wound healing, hair loss, eyesight, exercise performance and
00:02:44.560
recovery, metabolic health, fat loss, inflammation, chronic pain, and a lot more. So with all that said,
00:02:51.760
anything you want to add before we get rolling into it? Two unrelated things. I noticed you have a
00:02:57.380
little visitor for the podcast today, hanging out with you there. Hopefully he's interested and this is
00:03:02.960
something he'll like. And secondly, I would add that my wife is specifically asking me these questions.
00:03:09.940
So she's very keen to buy a whole bunch of red light things. And I asked her to just hold off until
00:03:17.020
we did the research for this episode so that we could at least have a sense of if there's value there,
00:03:22.820
where it is. I don't know if she's a subscriber though. So if she's not, this might be the one that
00:03:27.520
she subscribes for. I respect that when your wife asks you medical questions, you say, let me send
00:03:33.760
you a podcast episode instead of telling her the answer like everyone else. So it's good to know you
00:03:39.900
practice what you preach even through your direct family. Okay. First question. I think it's going to
00:03:46.340
be helpful to just explain when we say red light therapy, what does that even mean?
00:03:51.740
Yeah. You can't do this without at least having some understanding of the physics and the principles
00:03:57.200
that define light and waves come up over and over and over again, as you try to evaluate the
00:04:03.160
plausibility of the claims that are made here. So when we're sitting here looking out at the world,
00:04:09.140
we're looking at light and there's visible colors of light. Maybe I should take a step back.
00:04:15.140
Light exists as waves and they're very short waves to be clear. So sound waves are really,
00:04:21.280
really long. Light waves are really, really short. And then obviously waves can get much,
00:04:26.660
much shorter and you can get into UV, which we've talked about in detail on a previous podcast.
00:04:31.700
And then even shorter than that would be x-rays. And then even shorter than that are gamma rays. So
00:04:36.000
as wavelengths get shorter, the energy gets more powerful. But if we just focus on light,
00:04:41.420
visible light runs the gamut from about 380 nanometers, which would be purple-ish. And then all
00:04:50.620
the way at the longest end, about twice that 780 nanometers is where red light is. So when people
00:04:59.160
talk about red light therapy, they're mostly talking about light that is in that very narrow band. So for
00:05:07.240
example, again, a white light is giving you all mixed across that entire range. Red light would be
00:05:12.460
more narrowly focused. It's also important to understand that, and we'll talk about this a little
00:05:18.620
bit today. Phototherapy in general involves wavelengths across that entire band of visible
00:05:26.120
light, but it also includes something called near infrared. So that basically runs the gamut from about
00:05:34.440
400 to 1100 nanometers. So I think the easiest way to think about this is red light therapy,
00:05:43.320
which runs about 620 to 780 nanometers. And then near infrared, which is right adjacent to that,
00:05:51.720
the next thing up in terms of length, which is about 790 to 1400. So again, if you forget everything else,
00:06:00.420
just remember when people talk about red light therapy, they're talking about wavelengths that are
00:06:05.440
just in that red visible area of 620 to 780. And then often they talk about near infrared as well,
00:06:13.860
which is not visible. To be clear, you don't see it, but it's just a little bit longer, 790 to 1400
00:06:20.200
nanometers. We'll come back to this over and over again, because there are some instances where the
00:06:26.660
fact that you can't see it might actually make it a little more dangerous. Double clicking on red light
00:06:32.760
therapy. Can we explain a little bit more about what is special about it and why there's so much
00:06:38.680
emphasis on it as talked about for the various claims that we'll speak about today? People who
00:06:44.940
listened to our podcast on ultraviolet light may recall a distinction I made between UVA and UVB,
00:06:53.840
which came down to the degree of penetration. And so similarly, when you think about red light
00:07:00.620
therapy and you remember that the longer a wavelength, the more it can penetrate, albeit with
00:07:07.580
less energy, what makes red light interesting is it is sort of at this sweet spot where it has some
00:07:13.560
capacity to penetrate more so than other forms of visible light. That's sort of part of what makes
00:07:21.500
this interesting. Now, the exact depth that's reached by the red light or the near infrared is kind
00:07:28.180
of a function of how the light beams are organized. So what is the amount of coherence, which is how
00:07:35.800
much do the wavelengths line up with each other? So if the wavelengths are all coherent, the peaks and
00:07:41.020
valleys are in the same place. It's going to have more penetrance. And then what's the extent to which
00:07:46.060
they're all aligned in the exact same direction? That's called collimation. So in other words, the light
00:07:51.520
isn't spreading, but rather it's all pointed in the exact same direction. And then finally, you have the
00:07:56.880
intensity. And we'll talk a little bit about the difference between watts and joules, because if
00:08:00.600
people are looking at these devices, sometimes they give you information in watts and sometimes
00:08:05.340
they give you information in joules, which of course, there's a very clear relationship between
00:08:09.500
them. And of course, broadly speaking, energy matters as well. So when you take all of that into
00:08:15.160
account, though, the really important principle that I think gets perhaps missed when people evaluate
00:08:21.620
these things is that for the most part, red light can't penetrate nearly as much as people think it
00:08:27.960
can. OK, if red light is being delivered by LEDs, which is the most common way that it is, it's going
00:08:34.660
to be able to penetrate about two to three millimeters into skin. Now, infrared light can go a
00:08:42.180
little bit deeper because remember, it's a longer wavelength and it can reach probably five to ten
00:08:46.800
millimeters. Now, if red light is delivered by a laser, because again, you now have a more focused
00:08:53.400
form of light energy, it could penetrate significantly higher than that. It could go
00:08:58.180
from one to four centimeters. So again, keep in mind the way that the light is organized plays a
00:09:05.180
significant role in the depth that it can penetrate. Now, if you start to think about some of the
00:09:10.140
applications we're going to talk about, when you start to think about red light therapy, just keep in the
00:09:16.180
back of your mind. If something can only penetrate one to three millimeters, it's going to be difficult
00:09:22.700
for it to have some of the profound effects that are sometimes claimed. Even if something can penetrate
00:09:28.640
10 millimeters or a centimeter, which would be quite deep, it's not clear that that's going to be able to
00:09:34.100
have a significant effect. And so as a general rule of thumb, the more superficial the application,
00:09:41.240
the more plausible I think it's going to be as we go through these. Last foundational question before we
00:09:47.600
get to the various claims and where this could be beneficial or not is, in general, what happens when
00:09:54.580
the tissue is exposed to red light? This is an important and as you said, foundational question.
00:10:01.260
So to have any biologic effect, the light needs to be absorbed by some photosensitive molecule
00:10:09.340
within the cell or tissue that it's hitting. And so the absorption of light by these photosensitive
00:10:16.380
molecules, which are called chromophores, cause a localized chemical change or a photochemical reaction.
00:10:23.920
Now, the most interesting of these is probably something called cytochrome C oxidase or CCO. It's a
00:10:33.000
component of the electron transport chain within mitochondria. And generally speaking,
00:10:39.340
most people who are proponents of red light therapy point to cytochrome C oxidase or CCO as the main
00:10:48.180
target and therefore the mediating effect of the biologic impact of red light. So red light and near
00:10:56.860
infrared wavelengths do seem to excite cytochrome C oxidase and its activity then increases subsequent
00:11:04.600
ATP production. Conversely, blue and green wavelengths, remember these are shorter, less
00:11:11.600
penetrant, but more powerful, seem to decrease the activity of CCO and subsequently decrease ATP
00:11:17.920
production. Now kind of getting into various claims of where red light therapy can be beneficial or not,
00:11:24.160
I think it'd help to maybe start with what do we know about the idea that red light therapy
00:11:32.440
Thank you for listening to today's sneak peek AMA episode of The Drive. If you're interested in hearing
00:11:38.700
the complete version of this AMA, you'll want to become a premium member. It's extremely important to
00:11:44.260
me to provide all of this content without relying on paid ads. To do this, our work is made entirely
00:11:49.500
possible by our members. And in return, we offer exclusive member only content and benefits above and
00:11:56.140
beyond what is available for free. So if you want to take your knowledge of this space to the next
00:12:00.460
level, it's our goal to ensure members get back much more than the price of the subscription.
00:12:05.620
Premium membership includes several benefits. First, comprehensive podcast show notes that detail
00:12:11.740
every topic, paper, person, and thing that we discuss in each episode. And the word on the street is
00:12:17.580
nobody's show notes rival ours. Second, monthly ask me anything or AMA episodes. These episodes are
00:12:25.440
comprised of detailed responses to subscriber questions typically focused on a single topic
00:12:30.320
and are designed to offer a great deal of clarity and detail on topics of special interest to our
00:12:35.680
members. You'll also get access to the show notes for these episodes, of course. Third, delivery of our
00:12:41.560
premium newsletter, which is put together by our dedicated team of research analysts. This newsletter
00:12:46.960
covers a wide range of topics related to longevity and provides much more detail than our free weekly
00:12:53.180
newsletter. Fourth, access to our private podcast feed that provides you with access to every episode,
00:13:00.060
including AMA's sans the spiel you're listening to now and in your regular podcast feed. Fifth,
00:13:07.000
the qualies, an additional member only podcast we put together that serves as a highlight reel featuring
00:13:13.180
the best excerpts from previous episodes of the drive. This is a great way to catch up on previous episodes
00:13:18.940
without having to go back and listen to each one of them. And finally, other benefits that are added
00:13:23.740
along the way. If you want to learn more and access these member only benefits, you can head over to
00:13:29.280
peteratiamd.com forward slash subscribe. You can also find me on YouTube, Instagram, and Twitter,
00:13:36.220
all with the handle peteratiamd. You can also leave us a review on Apple podcasts or whatever podcast
00:13:42.800
player you use. This podcast is for general informational purposes only and does not
00:13:48.000
constitute the practice of medicine, nursing, or other professional healthcare services,
00:13:51.960
including the giving of medical advice. No doctor patient relationship is formed. The use of this
00:13:57.980
information and the materials linked to this podcast is at the user's own risk. The content on
00:14:03.960
this podcast is not intended to be a substitute for professional medical advice, diagnosis, or treatment.
00:14:09.000
Users should not disregard or delay in obtaining medical advice from any medical condition they
00:14:14.180
have, and they should seek the assistance of their healthcare professionals for any such conditions.
00:14:19.600
Finally, I take all conflicts of interest very seriously. For all of my disclosures and the companies
00:14:25.040
I invest in or advise, please visit peteratiamd.com forward slash about where I keep an up-to-date
00:14:39.000
For all of my disclosures, please visit peteratiamd.com forward slash about where I keep going.