AMA #65: Red light therapy: promising applications, mixed evidence, and impact on health and aging

**Peter Attia** (0:10)
Hey, everyone, welcome to a sneak peek, Ask Me Anything or AMA episode of the Drive podcast. I'm your host, Peter Attia. At the end of this short episode, I'll explain how you can access the AMA episodes in full, along with a ton of other membership benefits we've created. Or you can learn more now by going to peterattiamd.com/subscribe. So without further delay, here's today's sneak peek of the Ask Me Anything episode.
Welcome to Ask Me Anything episode 65 I'm once again joined by my co-host, Nick Stenson. In today's episode, we cover red light therapy. It's a topic we get asked about all the time. In fact, my wife asked me about it all 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. We then break down the various forms of red light therapy and their various treatments into whether or not I think they are beneficial. In other words, we go through each application and review the data for them. So these include red light therapy for aging in general, skin health and acne, wound healing, hair loss, eye health, exercise performance and recovery, metabolic health, general weight loss, spot fat loss, inflammation, injury rehab, and menstrual cramps for women. So in other words, we go through each of these and do a detailed analysis of the literature. We close this conversation by summarizing my overall takeaways for each use case and explain via a summary table that we created that breaks down everything you might want to know to understand this. If you're a subscriber and you want to watch the full video of this podcast, you can find it on the show notes page. If you're not a subscriber, you can watch a sneak peek of the video on our YouTube page. So without further delay, I hope you enjoy AMA number 65

**Nick Stenson** (2:07)
Peter, welcome to another AMA, how are you doing?

**Peter Attia** (2:09)
Good, thanks for having me back.

**Nick Stenson** (2:11)
Anytime, anytime. So today's AMA, we are going to focus on a single topic, which is red light therapy. This is something we get asked about a lot, not only questions from the website and subscribers, but I know through your patients as well. And so we compiled all these questions, and through this conversation, hopefully going to cover what red light therapy is, how it can work, deep dive into some various claims out there around red light therapy. This can include potential effect on skin health, wound healing, hair loss, eyesight, exercise performance and recovery, metabolic health, fat loss, inflammation, chronic pain and a lot more. So with all that said, anything you want to add before we get rolling into it.

**Peter Attia** (2:55)
Two unrelated things. I notice you have a little visitor for the podcast today, hanging out with you there. Hopefully, he's interested and this is something he'll like. And secondly, I would add that my wife is specifically asking me these questions. So she's very keen to buy a whole bunch of red light things, and I asked her to just hold off until we did the research for this episode, so that we could at least have a sense of if there's value there where it is. I don't know if she's a subscriber though, so if she's not, this might be the one that she subscribes for.

**Nick Stenson** (3:29)
I respect that when your wife asks you medical questions, you say, let me send you a podcast episode instead of telling her the answer like everyone else. So it's good to know you practice what you preach even through your direct family. Okay, first question, I think it's going to be helpful to just explain, when we say red light therapy, what does that even mean?

**Peter Attia** (3:52)
Yeah, you can't do this without at least having some understanding of the physics and the principles that define light and waves come up over and over and over again as you try to evaluate the plausibility of the claims that are made here. So when we're sitting here looking out at the world, we're looking at light and there's visible colors of light. Maybe I should take a step back. Light exists as waves, and they're very short waves to be clear. So sound waves are really, really long. Light waves are really, really short. And then obviously waves can get much, much shorter and you can get into UV, which we've talked about in detail on a previous podcast. And then even shorter than that would be X-rays. And then even shorter than that are gamma rays. So as wavelengths get shorter, the energy gets more powerful. But if we just focus on light, visible light runs the gamut from about 380 nanometers, which would be purple-ish. And then all the way at the longest end, about twice that, 780 nanometers is where red light is. So when people talk about red light therapy, they're mostly talking about light that is in that very narrow band. So for example, again, a white light is giving you all mixed across that entire range. Red light would be more narrowly focused. It's also important to understand that, and we'll talk about this a little bit today, phototherapy in general involves wavelengths across that entire band of visible light, but it also includes something called near-infrared. So that basically runs the gamut from about 400 to 1100 nanometers. So I think the easiest way to think about this is red light therapy, which it runs about 620 to 780 nanometers, and then near-infrared, which is right adjacent to that, the next thing up in terms of length, which is about 790 to 1400 So again, if you forget everything else, just remember, when people talk about red light therapy, they're talking about wavelengths that are just in that red visible area of 620 to 780