That’s interesting. I’ve never heard the potential connection with autophagy before. I have read tons of studies on red/NIR light and never saw any evidence that it increased autophagy in animals so I doubt it does that in animals in vivo. Note that this study you linked to used far infrared light not near infrared light. The wavelengths used in the study are a good bit longer than those used and found effective for photobiomodulation so this may not apply to shorter infrared light. Oddly I see no mention of the irradiance and dose they used in the study so it’s hard to determine whether this has any relevance to what might happen in vivo.
Quite a few search results come up. This seems to be the right wavelength.
I don’t see the relevance of this. This study is about light exposure to the eyes, not about red/NIR light. Of course the eyes will respond to various wavelengths of visible light because they have specific receptors to detect it. This will not apply to the rest of the cells in the body.
Initially i found this:
However, it does not give references to the original source data:
Different light wavelengths impact human skin in different ways. As per research, LED light-induced autophagy in hippocampal neuron cells. Moreover, red light therapy at 635 nm triggers lipolysis and oxidizes fact in subcutaneous adipose tissue. In another research, red LED wavelength 550-670 nm accelerates skin healing.
The autophagy process increases the cell turnover. This is the exact mechanism that rejuvenates the dermal layers. Moreover, autophagy prevents muscle loss that often comes with aging. Red LED therapy may rejuvenate skin, support cell turnover, and heal wounds.
Thanks for the condescending/patronizing response. Since plants and trees w/leaves reflect near-infrared light, it’s possible to sit in the shade on a sunny day and receive near-IR without necessarily feeling warm/hot, so I don’t know if the “warmth test” is always valid.
My apologies. It was not meant in a patronizing way. I should perhaps have put emphasis on if in “if you think of the fact…”. Many people don’t think of the fact that infrared light heats the skin so they don’t think of that as a proxy for exposure.
Anyways, regarding your point on plants and tree leaves reflectinig near-infrared light, that’s an interesting fact. The dose of red/NIR light however would be much lower if you’re sitting in the shadow of a tree so I think the reason the heat test wouldn’t work well in that case is not because your skin doesn’t get heated, rather it’s because the dose you get of red/NIR light is so low that you won’t notice the small heating. While the leaves reflect red/NIR light, a lot of it will get reflected in other directions, not towards you. Think of holding a white cotton T-shirt against the sun between your face and the sun. Some of the visible light gets through but some will be reflected off the shirt in various directions. A lot of the reflected light will be reflected back towards the sun or in various other directions away from you, with only some of it reflfected directly towards you, so overall a lot less than half of the light actually ends up on your face. The reflection of red/NIR light off plants and leaves is not exactly the same as this, but I think it’s quite similar. The result is that you do get red/NIR exposure when sitting under the cover of plants and trees, but the portion that ends up reflecting onto you will be only a small percentage of what would end on you if no plants/trees were in the way. The warmth test kind of only works practically if the temperature increases enough for you to notice it.
This depends in part on how many leaves there are. If there is a lot of greenery all emitting some IR that will add up. I would think still less than direct sunlight, but not miniscule.
Yes it probably amounts to a good exposure, you just might need a few hours to get that dose.
Yes. I understand the point is we can be outside under the trees for a long time without uv damage and get a lot of NIR benefits
But vielight goes inside the nose which means more direct effects
Still, I don’t know if effect size is large with most of these in general cmpared to many many other things. Even a small effect size might be worth it if mental load of wearing them is low
I am doubtul that using qEEG is of significant benefits in terms of customizing the photobiomodulation regimen. That is not what has been done in the studies I have read where photobiomodulation was used on the brain.
I was listening to talks on this topic this weekend. The mechanisms are elusive but the effects are clearer. The red wavelengths have the effect of increasing ATP production…perhaps it has to do with effects on cellular water and/or a change in the mitochondrial membrane potential (charging the battery). Also interesting is how blue wavelengths have the opposite impact…it reduces ATP production. In the sunshine (all wavelengths) this all balances out. Indoors, with only blue light (LEDs) our mitochondria are less efficient (more ROS?). This would show up first in the cells that demand the most ATP…retina.
I am scheduling podcasts with people on this subject: Scott Zimmerman. Glen Jeffery. Other ideas?
The photobiomodulation study that got my attention was a randomized, double-blinded, placebo-controlled, split-face clinical trial from 2007.
It was the split-face design that I found compelling. They treated the right side of each participant’s face, but covered the left side so that it would remain untreated. This setup allowed for a within-subject comparison, where the treated and untreated sides could be directly compared for changes. The study also included a control group that received a sham light treatment.
Here’s what they found:
Among 76 participants, twice-weekly sessions of 633 nm red light therapy (totaling either 126 J/cm2or 44 J/cm2 depending on method of measurement) for four weeks reduced wrinkle severity (measured through average roughness) by 26% and melanin levels (measured through the Mexameter spectrometer) by 694%, while increasing gross elasticity by 14% (Lee et al. 2007). In all cases, no significant differences were seen on the within-patient covered side of the face or in the sham light control group.
The 19 participants who underwent biopsies displayed 1) an increase in the number of elastic fibers (Verhoeff-van Gieson stain; validated as normal with Alcian blue staining), 2) highly activated fibroblasts surrounded by thicker and more numerous collagen and elastic fibers (transmission electron microscopy), and 3) a 2.53-fold increase in Cx43 mRNA. For context, Cx43 is a gap junction protein that facilitates communication between cells.
There are plenty of other studies, but that one convinced me to purchase a smaller panel to use on my face. It’s a low-risk intervention with pretty good evidence—and it feels nice, too.
I would, however, mildly caution against using 830 nm near-infrared light (as opposed to ~633 nm red light) close to your hair. There’s a small amount of evidence that it can inhibit enzymes related to melanin production, which means 830 nm NIR could exacerbate graying hair.
In primary cultured human melanocytes and a 3D-mixed cell culture system, near-infrared (NIR) light at 830 nm (5, 10 and 20 J/cm2) reduced tyrosinase, TRP-1, TRP-2, and MITF—inhibiting melanin synthesis in vitro and ex vivo in a dose-dependent manner (Kim et al. 2012). LED irradiation at 850 nm has a similar, but attenuated effect on melanin production.
Seriously, though, this is just one study. So I weight it lightly.
On the other hand, 830 nm NIR will have significantly greater penetration. If used with an NIR helmet, it actually penetrates through the skull into the brain. The usefulness as a brain photobiomodulation intervention is a subject for another discussion.
For me, the subject of gray hair is a moot point.
I doubt this effect is significant because if it were, then people with a buzz cut that don’t wear a hat and stay out in the sun a lot would get gray hair from the infrared radiation from the sun, but this does not seem to be the case. In any case, if the mechanism of greying is merely inhibition of enzymes like tyrosinase, then the effect would be temporary and not a result of any permanent damage to the melanocytes.
FWIW, I have heard that people who spend a lot of time on submarines tend to get gray hair (& have few wrinkles). Google doesn’t have anything to say on this & I don’t remember where I heard it. I mainly remember looking at an ex-submariner & noticing his fully gray hair & smooth skin.
Pure rumor to you …
That makes sense. People spending a lot of time in a submarine should experience less skin photoaging form the lack of UV light exposure. At the same time they might get premature hair greying from all the stress involved in working on a submarine.
An excellent (and reassuring) point. Inhibiting enzymes related to melanin synthesis aren’t likely to affect the fundamental biology of graying hair (e.g. loss of melanocyte stem cells)—just orthogonally exacerbate attempts to hold off the gray.
The study dosed 830 nm NIR at 5, 10, and 20 J/cm2. Coming into this conversation, I honestly didn’t know how that compares to the NIR energy outputs we receive from the sun. So, out of curiosity, I visited Wolfram Alpha for some help.
- At solar noon, the irradiance is around 1000 W/m2 at ground level. This is the power per unit area from the Sun.
- The near-infrared (NIR) region (700–2500 nm) accounts for roughly 47% of solar irradiance. So, that puts the power from NIR light around 470 W/m2.
- At 830 nm, the solar spectral irradiance is around 1.5 W/m2/nm. So a 10 nm band around 830 nm (from 825 nm to 835 nm) yields 0.0015 W/cm2.
- Adding the element of time: 0.0015 W/cm2 × 3600s = 5.4 J/cm2 for one hour of peak sunlight exposure.
I wouldn’t put too much stock in that, but I wanted to get a general sense of scale. Based on those rough numbers, I’d say it’s reasonable to think that spending a few hours in direct peak sun could match the exposures from (Kim et al. 2012). In any case, I suspect it would require a bit of analysis to tease apart the ways sunlight exposure could contribute to hair pigmentation (including negatives like UV damage and positives like adequate vitamin D).
I didn’t mean to fall down this rabbit hole (and I’m not particularly concerned about NIR exposure for gray hair), but it is worth considering that these panels can deliver more energy of particular wavelengths than we’re likely to receive from the sun.
I got my knowledge on photobiomodulation from reading tons of studies on it, not from reading material from or listening to any particular experts, so unfortunately I don’t have a good idea of people to include in a podcast about it.
The estimate from Wolfran Alpha of 5.4 J/cm2 of 830 nm NIR for one hour of peak sunlight are not far off. In fact, the exposure from the sun can most likely be a good bit higher than that, in particular since you don’t just get 830 nm from the sun but also get longer wavelengths around 1000 nm that have the same effects and also penetrate deeply into the scalp. So yes, I do think that an hour in the sun when the sun is high can lead to an effective dose.