AMA #16: Sleep, Vertigo, TBI, OCD, Tips for Travelers, Gut-Brain Axis & More

Welcome to a special edition of the 16th Ask Me Anything (AMA) episode, part of Huberman Lab Premium, recorded in Sydney, Australia. This episode is a recording of a live stream AMA, originally exclusive to our Premium members. We've decided to make the full-length version available to everyone, including non-members of Huberman Lab Premium. Huberman Lab Premium was launched for two main reasons. First, it was launched in order to raise support for the main Huberman Lab podcast — which will continue to come out every Monday at zero-cost. Second, it was launched as a means to raise funds for important scientific research. A significant portion of proceeds from the Huberman Lab Premium subscription will fund human research (not animal models) selected by Dr. Huberman, with a dollar-for-dollar match from the Tiny Foundation. If you're not yet a member but enjoyed this full-length livestream AMA, we invite you to join Huberman Lab Premium. By subscribing, you'll gain access to exclusive benefits including our regular monthly full-length AMA episodes, AMA transcripts, podcast episode transcripts, early access to live events and more. Additionally, a significant portion of your membership proceeds contributes to advancing human scientific research. You can learn more about the research we were able to support in our Annual Letter 2023. If you're a Huberman Lab Premium member, you can access the transcript for this AMA episode here. Timestamps (00:00:00) Introduction (00:02:34) Achieving Key Health Pillars While Traveling (00:07:11) Improving Sleep Quality (00:13:11) Understanding and Managing Vertigo (00:20:44) Enhancing Brain Function Post-TBI (00:26:58) Getting Closer to Unraveling OCD (00:30:44) Adjusting Circadian Rhythms for Travel (00:34:58) Optimal Dosage for Fish Oil Supplements (00:40:17) Monitoring Hormone Levels (00:46:09) Optimizing the Gut-Brain Axis (00:52:04) Best Practices for Tongue Cleaning (00:56:36) Conclusion & Thank You Disclaimer Learn more about your ad choices. Visit megaphone.fm/adchoices

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Andrew D. Huberman?

  Welcome to the Huberman Lab Podcast, where we discuss science and science-based tools for everyday life.

• 0:09Andrew D. Huberman?

  Hello, everybody, and welcome.

• 0:12Andrew D. Huberman?

  I want to thank all of you premium Huberman Lab Podcast subscribers for joining. This is an exciting one, even though the backdrop here looks very much like the studio back in the United States. I am doing this AMA live from Sydney, Australia, where I and the Huberman Lab Podcast team have been for well over a week. We were in Melbourne, and we just did two live shows here in Sydney, and we're headed off to Brisbane tomorrow, and it's been absolutely delightful. We've had so much fun talking science, learning from people. It's a wonderful place. I want to get right into your questions and do my best to answer as many of them as

• 0:54Andrew D. Huberman?

  possible, as thoroughly, clearly, and succinctly as possible over the next hour. So I'm going to dive into those in just a moment. Just one last important thing before I do that, which is that I want to thank everyone for being a premium subscriber and let you know that we, based on your contributions to the premium channel, have already, as you know, supported four laboratories at Stanford, Columbia University, Salk Institute, and elsewhere for important projects on humans that are already leading to important therapeutic breakthroughs that we will soon share with you on the Huberman Lab Podcast, but that this year, 2024, we were fortunate enough

• 1:35Andrew D. Huberman?

  to secure no fewer than three dollar-for-dollar match donors who have generously agreed to match our contributions from the premium channel to additional projects. Those are going to head out to a number of different universities and researchers working, again, on human studies, so no animal studies, human studies on important projects, everything from Novel treatments for mental health issues, headache and migraine, some interesting stuff on immunology and cancer, mindsets and immune system function, and much, much more, also nutrition, physiology, exercise physiology, et cetera. So your contributions to the premium channel really do make a difference. I can say this because I'm familiar with

• 2:20Andrew D. Huberman?

  the challenges of raising funding for doing truly breakthrough work and getting things quickly out to the general public. So, thank you, thank you, thank you. And now, without further ado, let's get to your questions. The first question was, is, how are you managing to achieve your key health pillars while in Australia and any other place you've enjoyed doing so, all while working so hard? Well, thanks for the question. I'll answer this question in the context of what I think we all can and should and really will do, because if you're a premium channel subscriber, certainly you're taking your health seriously. So, first off, I think there's a bit of a misconception about the protocols on the Huberman Lab Podcast,

• 3:04Andrew D. Huberman?

  being that we are all, including myself, super, super regimented about them to the point where we don't enjoy other things in life, and that's simply not true. So, I view the protocols of the Huberman Lab Podcast as science-based, actionable, low cost, zero cost, minimal cost in almost all situations. There are a few exceptions to that, but it really designed to mesh with the rest of life and enhance mental health and physical health, which of course means remaining social, staying on typical sleep schedules, et cetera. So, the big ones for me when arriving here were, of course, to get morning sunlight as often as possible. Saw a beautiful sunrise this morning over Sydney, but even on the overcast days, we've had a few rainy overcast days to really make it a point to get outside and to get that morning sunlight. Also, our crew did travel in with

• 3:50Andrew D. Huberman?

  A red light, not a red light panel, although I do have a couple of red light panels, those little portable ones that I use from time to time. The red lights I'm referring to in reference to answering this question are the red lights, which are just red light bulb that we, I actually travel with a little red light bulb unit. It's just like a small, you know, screw in unit. You plug it in here with an adapter, of course. And then in the evening, we've switched off the lights in the place where we're staying and it just brings the overall levels of cortisol down low very quickly and it makes it very easy to get to sleep each night. It makes a big, big difference. And this is a very low cost tool. You could essentially purchase any red light, even red party lights and put those up and then switch off the regular

• 4:33Andrew D. Huberman?

  overhead lights. It makes a big difference. It's probably even cost saving. We've also stayed fairly regimented about exercise. So this morning, took a great jog down to the ocean, jumped in the ocean. If you don't have access to an ocean on vacation, just getting outside and getting some movement early in the day can help shift your rhythm. Really the quadfecta of shifting your circadian rhythm in a new place or becoming an early riser, if you want to do that, is morning sunlight, movement, social engagement, and in my case, caffeine, although some people would opt for eating breakfast. I just happen to prefer to eat a little bit later in the day. So when you combine those things, you are really amplifying that morning cortisol increase that I've talked about on the podcast. Morning catecholamine

• 5:14Andrew D. Huberman?

  release, so dopamine, epinephrine and norepinephrine. And those act in synergy to create more early day and daytime mood focus and alertness and enhance the transition to nighttime sleep. But of course, that dimming of the lights and maybe even red light in the evening really, really can help. And so those are the biggies. And then, of course, if you want to shift your circadian rhythm really quickly to be on a local schedule, it helps to hop on the local meal schedule. But for me, that always means skipping breakfast. I'm not a big breakfast eater. I like lunch, an afternoon snack sometimes, and dinner. So when you do all of those things, it makes it very easy to stay with the health pillars. And of course, stress control is important. We're doing lives. There's a lot of work to do. So there's A daily for me, non-sleep deep rest or yoga nidra protocol. By the way,

• 5:58Andrew D. Huberman?

  you may be familiar with non-sleep deep rest and yoga nidra terrific zero cost practice for reducing stress, replacing or replenishing dopamine and mental and physical vigor. I've talked about this and the studies that support this on the podcast. There is a Huberman NSDR script on YouTube. That's again, zero cost. But while down here, we recorded a 10 minute, 20 minute and 30 minute NSDR script with a view of a beautiful Sydney sunrise. Those should be posted to our Huberman Lab Clips channel in the not too distant future, probably in the next couple of weeks. And then you can have different duration NSDR scripts that you can use, again, completely zero cost anytime you like. We've recorded also some additional meditations and we're considering

• 6:41Andrew D. Huberman?

  putting out a Spotify album, if you will, of NSDR and meditations that are science-based of different duration. So if you like that idea, maybe just give a shout into the internet and hopefully we'll hear it or put a comment on the latest episode of the Huberman Lab Podcast on YouTube. And if that sounds like a good idea to you, we will do more of that. These are again, zero cost, zero to access tools for enhancing mental health and physical health. So combining all of those is really what we've done. Next question was, is I have followed your sleep advice and I have seen a huge improvement. Great. Happy to hear that. Wonderful. But I still wake up at night and only get five or six hours. Is that enough? Can you please give more advice if possible?

• 7:27Andrew D. Huberman?

  Well, first of all, thanks for tuning into the sleep advice. So the question of whether or not five or six hours is enough really depends on person, context, and by context, I mean it can even change across the course of the year by life circumstances. The criteria for insomnia are very clear. Insomnia is excessive daytime sleepiness due to lack of sleep at night. Excessive daytime sleepiness due to lack of sleep at night. So if you're not falling asleep during the day and you feel reasonably good throughout the day, maybe you only need a brief 10 minute to 30 minute nap in the afternoon. Some people nap, some people don't like to nap, doesn't matter. But if you feel pretty good throughout the day and you have enough mental and physical energy and focus to complete the activities you need to complete, then I wouldn't worry

• 8:10Andrew D. Huberman?

  so much about five to six hours and I wouldn't obsess over, you know, these kind of scary things that we hear, oh, if we're not getting seven to eight hours that we get dementia, et cetera, because that's not necessarily the case. Everyone has different sleep needs. The other thing, and this is perhaps the most important thing for everybody listening to this really to think about is Q Q R T, which is quality, quantity, timing, excuse me, quality, quantity, regularity and timing. Q Q R T, Q Q R T, which is an acronym coined by the great Matt Walker, author of the book, Why We Sleep. He has his own terrific podcast in his own right, has a series on the Human Mind Lab podcast coming out soon. Q Q R T is what you really need to think about when you think about your sleep.

• 8:54Andrew D. Huberman?

  So you want to think about the quantity. How much are you getting? Well, you, Rema, who asked this question, are getting five to six hours a night. Okay, what about the quality of that sleep? Is it consistently five to six hours with no breaks or is there a break in the middle? One trip to the restroom in the middle of the night is considered normal and healthy for most people. If you're making multiple trips to the restroom in the middle of the night, you're waking up multiple times throughout the night on a regular basis, that's something to try and overcome. So the quality piece is important. Also, whether or not you remember your dreams or you don't, you want to make sure that you're getting ample amounts of slow wave sleep, which dominates the first half of your sleep night, and rapid eye movement sleep, which dominates the second half of

• 9:34Andrew D. Huberman?

  your sleep night, because they have different roles in recovery of brain and body, namely, slow wave, AKA deep sleep, is responsible for growth hormone release, rapid eye movement sleep responsible for the unpacking or the uncoupling of emotions to prior day and previous day experiences, and in that way acts as a kind of scrubbing out or a therapy for your emotional state. So are you feeling emotionally rested when you wake up is a good indication of whether or not you're getting enough rapid eye movement sleep. Some people like sleep trackers, using their aid sleep or their whoop or their Oura ring or something like that. I'm a fan of sleep trackers, but I think that relying too heavily on sleep scores can be risky. There are data from Ali Crumb's lab at Stanford.

• 10:20Andrew D. Huberman?

  Showing that if people receive a poor sleep score, even though they sleep well, their performance will drop. If people get a good sleep score, even though their their sleep was lousy, their performance is maintained or even enhanced. So you don't want to take any one sleep score and over interpret it. You want to look at the average and compare that to your subjective experience of sleep. Maybe I would say go about halfway through your day if you can bear to do it before looking at your sleep score and see how you feel. Then look at your sleep score as opposed to the other way around. That might be a good way to adjust for that belief effect I just mentioned. But if you're getting enough quantity, let's say you get five to six hours and quality you're sleeping through that bout,

• 10:59Andrew D. Huberman?

  maybe with one epoch of waking up. And then the regularity of your sleep is that you're going to sleep more or less at the same time each night, plus or minus an hour on, let's say, five to six days per week, because sometimes we like to stay up on a weekend night and have some fun or something like that. And then the timing, you know, where that sleep is falling in your 24 hour schedule is really key. And here's what we're learning as a field, that for many people who are early to bed, early to rise types, if they go to bed around 9:00 PM, 9:30, and they only get six hours of sleep, they feel great. Whereas if they get the equivalent amount of sleep, but go to bed at 11:00 PM or midnight,

• 11:41Andrew D. Huberman?

  they feel lousy. Similarly, if you're a night owl, you're somebody that really prefers to go to bed around 1:00 or 2:00 AM and wake up around, let's say, 10:00 AM. If you take that equivalent amount of sleep and you go to bed earlier, you're going to feel not so good. So getting the timing of your sleep in the 24 hour cycle correct and fairly consistent, that's the R part of Q Q R T, correct, is going to be beneficial. So I wouldn't worry so much about five to six hours only. Here's what I would do, Reema. I would take that five to six hours. And before getting out of bed each morning, I would do a 10 to 30 minute NSDR non sleep deep rest protocol, which will allow you to feel deeply rested.

• 12:22Andrew D. Huberman?

  And frankly, to recover whatever bits of sleep that you perhaps missed during the night. I found that to be a tremendously beneficial practice. Waking up, if I don't feel thoroughly rested, doing a 10 to 30 minute NSDR, then getting out of bed and continuing the day. And if you don't have time to do that, do that 10 minute, maybe 20 minute NSDR later in the day at any point. And I think you'll see terrific results, not just because you're recovering some sleep that you lost perhaps during the night, or maybe you just need five to six hours, but also because you'll get better at falling and staying deeply asleep through the practice of NSDR in the morning or at some point throughout the day. I wouldn't recommend anything else elaborate unless you're feeling really exhausted during the day.

• 13:05Andrew D. Huberman?

  In which case, then I would move to some of the more advanced sleep tools.

• 13:11Andrew D. Huberman?

  I've had vertigo, I should denounce, this is a question. I'm not just telling you about my vertigo. I've had vertigo on and off and wonder what causes it. Is it hormones, adrenals, autolysts moving around? Ah, this person knows about the cochlea. Hydration, virus exposure. Zenana, I think is how you pronounce your name. Forgive me if that's not the correct pronunciation, Zenana. So vertigo is very interesting. Unfortunately, it's uncomfortable, but we can learn a thing or two right now that should be able to help you, Zenana and others, even if they haven't had vertigo. So vertigo, this perception of falling or dizziness, needs to be distinguished from lightheadedness. So if you're ever feeling dizzy, it's worth stopping and sitting,

• 13:55Andrew D. Huberman?

  or if you can't sit, standing and closing your eyes and asking yourself a question. Do I feel like I'm ready to fall straight down? Or do I feel like I'm going to spin and fall down? Because in answering that question, you can determine whether or not you are lightheaded. That would be the straight falling down. Or

• 14:20Andrew D. Huberman?

  You have vertigo, which is you're dizzy, which is that you're gonna spin and fall down. Now, do this in a safe place, please. You can do this while bracing yourself against a wall, or that's why I said ideally seated, so you don't actually fall. But in most cases, if you're feeling that spin, if you're feeling truly dizzy, you're feeling vertigo, and I'm moving my head around on purpose, then chances are you've got some issue in either your visual system or your inner ear. Okay, so since this is being recorded on video, I can display what I'm about to say. So your visual system and your inner ear system for balance have some really important features. I'm gonna make this a very quick tutorial.

• 15:01Andrew D. Huberman?

  Your head, as you move through space, is experiencing visual images going by all the time. Your retinas, your eyes, are essentially exposed to a lot of what's called visual slip. Imagine you're walking and you're trying to take a picture on your iPhone, or if you have an Android phone, on your Android phone, and you're moving, it's gonna be blurry, right? Well, there's a stabilization process in your body and brain, it's a magnificent one, that frankly is built into all jawed animals, whereby your head, because it can move forward, so think nodding, right? So this is pitch for you pilots, right? Yaw, moving from side to side, this would be the no. This would be the no, no.

• 15:44Andrew D. Huberman?

  So pitch, yaw, and roll, which would be like the puppy look, right? Pitch, yaw, and roll. Pitch, yaw, roll. Those are the three major angles of visual slip. And in an absolutely magnificent set of things, your inner ear has three hula hoop-like shaped structures. One that's arranged vertically, so up on its end. One that's at an angle of about 45 degrees to that. And another that sits like a hula hoop flat on the ground. And inside of each of those little hula hoop-like tubes, there are little stones called otolysts, okay, you heard that word earlier, that roll around on the bottom, just like marbles at the bottom of a hula hoop,

• 16:28Andrew D. Huberman?

  such that when you pitch, nod, the marbles in the vertical hula hoop slide back and forth. When you... Say no, the marbles in that hula hoop lying essentially parallel to the floor move around. And then the one at forty five degrees, when you roll your head from side to side, those move. And each of those sends neural signals that converge on the neural signals coming from the eye. And get this, when you move through space, there is a precise offset of whatever visual slip you happen to be experiencing by walking, the images are moving, you're looking up, you're looking at buildings, you're looking around, you're talking to somebody, they're moving their head.

• 17:09Andrew D. Huberman?

  And your eye is making little tiny movements, little microsaccades on the millisecond time scale that act as a perfect image stabilizer. So what this means, this is by the way, called the vestibulo-ocular reflex, vestibular system ocular reflex. And it's mediated through a structure called the cerebellum in the back of the brain. This is why when you're on a boat, when the horizon is tipping back and forth, I have to be careful of this because I have such a prominent seasickness based on a prior experience that if I think about this too much, I might get nauseous. When that horizon is moving around, your system becomes uncalibrated because you can't really keep the system jolting about in a regular way. I have to be really careful here, I'm getting dizzy.

• 17:54Andrew D. Huberman?

  Notice I said dizzy, not lightheaded. And you will end up disrupting that slip process and you'll essentially overcompensate, which is why whenever you feel sick on a boat, they say, look at the horizon, fixate to something at a distance. Okay, so if you have vertigo, almost certainly there's something going on in your inner ear. Yes, it can be caused by viruses. Yes, it could be caused by hormones. These things tend to be transient, but the most important thing is going to be to anchor the visual part of the vestibulo-ocular reflex. So what you're going to want to do is you're going to want to fixate on a point, maybe three or four feet away.

• 18:34Andrew D. Huberman?

  And then you're going to actually want to move closer to that point, or if you don't have access to it, you would want to look at your hand, your finger out in front of you, and then slowly move it in toward your nose. At some point, you'll feel like you're going to go cross-eyed and you can stop at that point, then move out again, then in again. What are you doing when you're doing this? What you're doing is you're overriding the error signals, the incorrect error signals. That exist in your kind of default setting at that when you have vertigo. And you're forcing the visual component to dominate and then your inner ear mechanisms will adjust to that. So this is a very powerful tool. If you ever feel nauseous or seasick, it's a very powerful tool. If you're ever in like me, you sit in the back of an Uber and then the Uber is too small.

• 19:17Andrew D. Huberman?

  You get out and you're like walk into a building where there are no windows. You're like, I don't really feel good. Get outside and look at a fixation point some distance away. This actually happened the other day. We went to the gym. We went inside this gym. We'd been in a, in a van and then went inside and weren't feeling well. So we decided to get out and just take a walk and fixate to the longest distance possible. The fresh air probably helped as well. But when doing that, you are anchoring the visual part of the vestibular ocular reflex. Now that's far and away better than trying to avoid moving your head to not get those little stones moving around in the semicircular canals. Lots to say about this. Um, I could go on and on, but hopefully you learned some biology and you learned to how to not be nauseous.

• 19:59Andrew D. Huberman?

  Um, if ever you feel dizzy or nauseous based on movement, motion sick. And we could talk about why you get motion sick, but it's through the vagus nerve, et cetera, et cetera. But this is a very useful tool. And if you're ever just not feeling well, you know, unless you have a fever or something like that, I recommend getting outside and looking at the furthest fixation point with your vision that you possibly can, and then walking toward it as far as you can safely. If not, by actually just doing a few of these, um, exercises of looking at your finger up close, that's going to be very good for anchoring the vestibular ocular reflex. And not every time, but many times people report feeling better, especially if you've moved from one closed environment to another closed environment, to another closed environment, and so on. Okay.

• 20:43Andrew D. Huberman?

  Next question is, what can be done to improve brain function for people that have been negatively impacted by things such as poor sleep, poor diet and TBI early in life? James. Yeah, this is a great question and I get this a lot. I think that, um, it reminds me that a lot of the conversation that we have on the podcast is about the good things that happen when you do things right and the bad things that happen when you do things wrong. And while I think that's an important conversation, what I've frankly failed to do enough, and that's why I'm grateful for this question, um, because it gives me the opportunity to talk more about the fact that your, your system is very. Robust. There is neuroplasticity. And also, you know, as my graduate advisor used to say, you know, time machine's broken, which is not to say, you know, you're out of luck.

• 21:27Andrew D. Huberman?

  But I wouldn't spend any extra energy thinking about how many seed, not seeds, excuse me, how many, I have to be careful. The seed oil debate is still a debate. It's unclear. How many trans fats you were exposed to in childhood? You know, we know trans fats are bad. Everyone agrees they're bad. Governments agree they're bad. This is perhaps one of the few things everybody agrees on in the nutrition space. Trans fats are bad. When I was growing up, trans fats were abundant in foods. There were probably fewer of certain things that we have more of now that are bad. But, you know, we ate a lot of trans fats. We had margarine in our fridge. There were other things that were probably weren't good for us that we consumed. And every once in a while, I'll think, gosh, you know, if I'd only been eating, you know, grass fed meats and fruits and vegetables and, and healthy

• 22:11Andrew D. Huberman?

  grains as I do now, back then, imagine how much healthier I'd be. But I really don't spend too much time on it. And I don't think you should either. I think the most important thing to remember is that biological systems, unless they're really damaged, you know, you're talking about a, you know, a major injury. And even then, they're very robust. You can overcome years, decades of poor use or misuse of those systems. That said, if you have the opportunity to take care of them now, I highly suggest you do. So for instance, if you haven't slept well for years, now's the time to get it right. I wouldn't worry about the past, truly. You can always rescue some of your health and health span

• 22:52Andrew D. Huberman?

  and lifespan. Poor diet, same thing. Just, it's a just do it kind of thing. Just hop on, hop on the train of getting things right 80 to 90% of the time. TBI, traumatic brain injury. Well, the episode of the Hubra Men Lab podcast is out right now with Dr. Mark Esposito. He's an MD and neurologist, originally trained at University of Pennsylvania, now at University of California, Berkeley. We talk about TBI. You know, there are a lot of different forms of TBI, different origins, you know, everything from bomb blast to car accident to construction work to just, you know, slipped on the stairs at a party. I know someone that slipped on, on some wet floor at a party and, you know, has a brain injury. What, what do we know? Well, you get back to the basics.

• 23:36Andrew D. Huberman?

  Sleep is going to be important, but there are some things like transcranial magnetic stimulation, certainly things that reduce brain inflammation like glymphatic outflow. So glymphatic outflow is this washing of the brain at night that removes debris. Very, very important in the weeks and months after traumatic brain injury to get adequate sleep for that reason. But then there are things that also seem to perhaps improve outcomes from traumatic brain injuries, such as hyperbaric chambers, so hyperoxygenation treatments, if you have access to those. Even things like elevating the feet slightly when you sleep by about five to 15 degrees is known to increase glymphatic flow during sleep, which can, we believe,

• 24:20Andrew D. Huberman?

  by way of increased clearance of a bunch of basically debris, reactive oxygen species within the cells, but also debris outside the cells in the extracellular space, so between neurons, so it isn't just empty space. There's all this like heavily glyco oscillated stuff, which basically just means this kind of like spongy carbohydrate stuff that fills in the spaces. The clearance of some of the metabolites and some of the debris that's accumulated there by just sleeping with feet slightly elevated, definitely not falling asleep in a chair upright. That's the worst thing for glymphatic flow, things like that. Some people go kind of bonkers on all things anti-inflammation. They start taking tons of curcumin and they kind of get obsessed with inflammation as the enemy. I wouldn't do that. In fact, there's some negative effects of things like curcumin,

• 25:03Andrew D. Huberman?

  turmeric, if you take it in high doses, like limiting the amount of dehydrotestosterone production, which is not good. You don't want that. Male or female, you don't want to take too much turmeric or curcumin. There are real issues with that. To say nothing of the studies that have shown lead contamination in a lot of turmeric, so you want to check the sourcing very carefully. If you do consume any turmeric, a little bit is probably fine. Cooking with it is fine, but we're here, we're talking about supplementation and, you know, just really not trying to turn inflammation into this terrible thing to the point where you're starting to do other things that are potentially damaging. There's some really interesting evidence that five grams, maybe 10 grams, depending on your body weight, of creatine monohydrate per day can enhance creatine phosphate

• 25:45Andrew D. Huberman?

  metabolism in the forebrain and enhance brain function under conditions of high altitude or TBI. I take five to 10 grams of creatine, just creatine monohydrate powder. Frankly, any creatine monohydrate powder should be sufficient. There are other forms of creatine. They are not any better. Creatine monohydrate is the least expensive, fortunately. That mixed in water, you take it with or without food. Some people ask, does creatine make your hair fall out? No, it does not make your hair fall out, but some people do experience an increase in DHT with with creatine monohydrate and there can be a DHT hair loss link. So if you think you're losing your hair from taking creatine, then stop and see, do the control experiment, it should grow back. But five to 10 grams of creatine monohydrate, something to explore hyperbaric chambers, something to explore excellent sleep, definitely do that.

• 26:30Andrew D. Huberman?

  And I just wouldn't obsess over past ills or wrongs to the extent that it impacts your ability to try and correct those in the present. I would say that about most everything, but then again, I understand that as humans, because we can remember the past, the present and the future, that sometimes, you know, it's difficult to let go of the mistakes of past that we made, but that's just simply being human and I don't have a solution to that.

• 26:59Andrew D. Huberman?

  Are we any closer to finding the cause of OCD? Well, I think we know what causes OCD. I think it's pretty clear that OCD is some form of miswiring in the basal ganglia, the structures of the brain that are involved in go action and no go withholding action type behaviors. And some malwiring of those structures to the dopamine reward system. Because here's what's interesting about OCD. OCD involves obsessions, obviously, that's the O in OCD. Compulsions, the actions, that's the C in OCD. But in a kind of weird twist of the neurology,

• 27:39Andrew D. Huberman?

  OCD is a situation where the compulsion does not remove the obsession, rather it exacerbates it. Okay, the compulsion does not remove the obsession, it exacerbates it. So unlike an itch that you scratch, with OCD, the scratching of the itch makes it worse, which is actually what we experience when we have a mosquito bite, which by the way, I absolutely loathe mosquito bites. It's one of my least favorite things in life. I have about 3,600 and counting pet peeves. That's definitely high on the list of those.

• 28:11Andrew D. Huberman?

  Obsessive compulsive disorder is one that really needs to be treated frankly neurologically. It's one for which there are behavioral interventions, but it's clear that adjusting the pharmacology of the neural circuits involved in OCD really can help. There again, there are behavioral treatments, but for severe cases of OCD, it's just very, very clear that interventions which include SSRIs, which have been demonized. A lot of people say, oh, selective serotonin reuptake inhibitors are terrible, blah, blah, blah. You know, the serotonin hypothesis of depression is untrue. Well, listen, the reality is this, that all treatments for depression that are effective, which include SSRIs, in some cases, cognitive behavioral treatments, all of these sorts

• 28:56Andrew D. Huberman?

  of things which have shown efficacy are all about what? They're not about serotonin, they're about neuroplasticity. That's why some antidepressants center on dopamine and norepinephrine, others center on serotonin, they're about neuroplasticity, they're about changing neural networks. They're not about neurochemical per se, but the neuromodulators such as serotonin allow an access point, they are a wedge into the neuroplasticity process. Now with OCD, in order to overcome these, these malwirings, it's very important to get plasticity. How do you get plasticity? Well, you, in my belief, you work with an excellent psychiatrist who can prescribe the appropriate dose of drug to release the appropriate amount of neuromodulator.

• 29:40Andrew D. Huberman?

  Then, and this is really key, you have opened up the window for plasticity, but then it's really important that the proper behaviors are engaged in. And when I did an episode on OCD, I talked about what some of these are. For instance, the person is exposed to the stimulus that causes the obsession, or maybe this obsession arises spontaneously, they feel the impulse to complete the compulsion, the behavior, and they resist with the support of a therapist, but they're doing this in the context of having elevated levels of serotonin or some other neuromodulator that then allows fewer trials of resistance, fewer times of needing to withhold the, the behavior that this person so badly wants to perform because it's coming from within, it's this compulsion, literally.

• 30:25Andrew D. Huberman?

  Then they are able to achieve plasticity more quickly. Perhaps also transcranial magnetic stimulation. So a conjunction of the correct behavior, the withholding behavior, maybe a replacement behavior that's often used, use a replacement behavior with the appropriate neurochemical milieu is the solution to OCD. Okay, next question is if I'm just going to New York City from San Francisco, how do I control shifting my circadian rhythm by only three hours? So if you're going to New York City from San Francisco, the best way frankly would be to get up an hour earlier, two days before you head off to New York and then another day you might try and shift by two hours before you go and then

• 31:08Andrew D. Huberman?

  head to New York and do the last shift on the last day. Most people won't do that. It's just, you know, it takes a little bit of work, but they just don't have the the time ability or your discipline to do that, but it is perhaps the best way. I would say the best thing to do is to know your temperature minimum, and I'll try and keep this pretty simple. If you typically wake up at 8:00 AM, let's say, just by way of example, that means that your minimum body temperature is at 6:00 AM, which means that if you want to get up earlier in the days where you travel to New York, well, in the couple of days before you leave, anytime between 6:00 AM and 10:00 AM, get some bright light in your eyes, even if you go back to sleep. So for instance, get up at 6:00 AM, set an alarm clock.

• 31:52Andrew D. Huberman?

  I know you normally like to get up at 8:00 AM, get up at 6:00 AM, get some bright light in your eyes from artificial sources or from sunlight, maybe five, 10 minutes, then go back to sleep until 8:00 AM. You do that again the next night and then you head off to New York. You'll find the shift to be much easier. Now here's what you don't want to do. You want to make sure that you do not view bright light before 6:00 AM. So in the middle of the night, if you get up, Need to use the restroom, trying to use dim lights as dim as is safely possible, et cetera. And what are you doing when you're doing this? Yeah, I could get into a long description of the science behind this and I'll probably do a podcast all about this at some point. But really what you're doing, if you get up at 6 a.m. and getting some bright light exposure is, if you think about it, you're kind of looking at a New York sunrise of sorts.

• 32:35Andrew D. Huberman?

  Okay. If it's not a sunrise, you're getting some bright light that mimics sunrise, at least to some extent. Nothing's quite like sunrise, but to some extent. So in that sense, even if you go back to sleep, what you're doing is you're sending the light signal, the zeitgeber, the time signal to your circadian clock of your hypothalamus that it should shift, that you'd need to get up earlier. And indeed, that will happen over the course of about two, three days. The other thing you can do, and I know this is, um, this is kind of rare these days to get an answer like this. The other thing you can do is just fly to New York and force yourself to get up and just drink caffeine and get out and exercise and use the social rhythm of the activity of the city in order to get up earlier. But you will feel lousy late morning. And so you

• 33:17Andrew D. Huberman?

  would only want to do that if you could access a brief nap of anywhere from 30 to 90 minutes late morning, and then you'll feel fine. But my suggestion would be to some, something back there, like some animal or something likes that answer so much. So like that, yeah, would be to just trying to get a little bit of light exposure a couple hours before your normal wake up time, then go back to sleep in the two days before you head off to New York City. And of course, everything here was set in the context of the New York City, um, it's a flight from San Francisco, New York City, but that, but the principle, the logic holds. And if you have any questions about this temperature minimum and wake up time, and you want to get your circadian clock right for

• 34:00Andrew D. Huberman?

  travel, check out the episode that we did on jet lag and shift work. And I'm realizing now as I say this, and I'm, and my team's here and they're listening, um, that I will do a video on the Hubert Room Lab Clips channel where I explain temperature minimum and how to Plug in your wake, normal wake up time in order to essentially arrive at whatever time shift you want. We should probably put that out as a newsletter too, where it's a little chart where it says, I currently wake up at 8 a.m. And then, which means my, and then it'll say subtract two hours. My temperature minimum is 6 a.m. And I want to travel to whatever it is, I don't know, Sydney, Australia on this date from this city. And then we know the time change and then I can tell you exactly what to do for a couple of days. I've done this for various military groups. I've

• 34:42Andrew D. Huberman?

  done this for people and close friends and who travel a lot and it works fabulously well. I can't eliminate jet lag for you. Don't I wish I could just eliminate jet lag? I can't do that, but I definitely can have the time that it takes for you to shift, maybe more.

• 34:58Andrew D. Huberman?

  Hi, hi. I love the Sydney show. Thank you. Thanks for coming out. Thanks for coming to Australia. Thanks for having us. I take fish oil, but I'm not sure I'm getting the dose right. What are your thoughts on fish oil and dose? I have lots of thoughts on fish oil. I think it's a terrific tool. I think every time I see a study or a news article saying fish oil not shown to, I just go, oh gosh, all right, well, listen, whoever's written, wrote that article, you know, I, I take no pleasure in your declining health span or lifespan, but whatsoever, but the rest of us are going to be taking fish oil. And here's why. There's just oh, so much evidence that getting enough omega-3 fatty acids is great for brain health, body health. And I think that the, the

• 35:42Andrew D. Huberman?

  issue around fish oil is typically around contaminants. So you want to make sure that it doesn't have loads of mercury. So things like sardines, cod liver oil, et cetera. You can get those from natural sources, except there's one problem. I hate sardines and I don't want to slurp down a bunch of cod fat. I'm just not interested in that. So if you eat a lot of fatty ocean fish and it's really clean fish, great. I don't. Most people don't. So I believe in taking a high quality fish oil. There are a lot of different sources of these. In fact, in the episode that we did with Dr. Rhonda Patrick, there's a link in the show note captions, I believe, that takes you to a chart of the different fish oil sources and their relative

• 36:23Andrew D. Huberman?

  levels of contaminants, et cetera. But most of the reputable brands out there are not going to have any contaminants because they've been cleaned out. It's been checked for. So I take the fish oil from AG1 or from Momentus. That's just me. There are a lot of other great sources out there. But I will say this, that's when I'm traveling and I take capsules. Typically, I like to take it in liquid form and I will take the, take it in liquid form. I have no financial relationship to the, to the liquid non capsule forms of fish oil. And I get the one that has a lemon flavor to overcome the absolutely disgusting flavor of cod liver oil. I guess, I don't know, presumably cod like the taste of cod liver oil, but I don't. So that's what I do. I'll take a tablespoon of that once a day in a protein shake. It tastes

• 37:06Andrew D. Huberman?

  like lemon. It doesn't taste like cod. Thank goodness. And when I travel, I take the capsules from AG1 or Momentus or their excellent ones from other sources. We have lots of great sources out there. Now, what are we trying to do when we take fish oil? Yes, it can reduce inflammation. Yes, it can do a number of different things, but that's all by way of omega-3 fatty acid intake, right? Most people get far too much omega-6, right? This is why there's a seed oil debate. We're not going to have that debate now. It would put us all to sleep, frankly. The key thing is to get enough omega-3s and they're hard to get unless you're eating krill. So unless you're a large, you know, baleen whale, you're probably not eating that much krill. If you're getting fatty fish, great. But when you take an omega-3 fatty acid in

• 37:51Andrew D. Huberman?

  the form of fish oil, or you eat sardines for that matter, what you're getting essentially is the substrate for a lot of other important building blocks, not the least of which is the lipid bilayer that surrounds the neurons of your, of your, of your brain. And so basically, the omega-3 fatty acids provide the substrate for some key building blocks of nerve cells and other cells in the brain and body. And, and this is- Perhaps the most important reason I can think of, when you get out past one gram of the EPA form of omega-3, okay, one gram of EPA form of omega-3 per day, it's clear there's a either mild to moderate antidepressant effect, so much so that one can, in some cases,

• 38:32Andrew D. Huberman?

  talk to your psychiatrist or psychologist, partially offset the dosage of any antidepressant. I am not telling you to go off antidepressant medication and go on to fish oil, that is not what I'm saying, I'm just saying that there's some impressive clinical trials showing that fish oil, if taken at dosages of one to three grams of EPA per day, can have a mild to moderate antidepressant effect, and I don't know anyone that wouldn't want to have better mood. So I take one and a half grams of EPA, which is not to say one and a half grams of fish oil, you need to look at the package and see how much fish oil, but then look at how much EPA, and typically, it's less than one gram per serving, so you may have to take two servings. Somebody will say, well, is it safe to take two servings? I don't see

• 39:14Andrew D. Huberman?

  any reason why not. And then, of course, there are the high potency fish oils, for which there is certainly one gram or more of EPA. Keep in mind that all this discussion about fish oil might sound kind of health food hippie store, forgive me hippies, health food store kind of stuff, but the reality is that EPA, high concentration EPA, is actually a prescription drug in the United States and elsewhere, prescribed often for enhancing mental health, enhancing cardiovascular health, and on and on. So, you know, we're not out on a limb, or out on a fin, as it were, when we're having this discussion, we're actually just talking about something for which there's a lot of clinical evidence, there's a lot of biochemical evidence, there's a lot of mechanisms. So I take anywhere from one to

• 39:57Andrew D. Huberman?

  two grams of EPA per day, even if that requires taking six, rather than the suggested three capsules per day, or taking a full tablespoon, or even two tablespoons of fish oil. And frankly, most people are getting too much omega-6 fatty acids, and not enough omega-3, so shout out to the fish oils. What is the recommended protocol for measuring hormone levels? Hmm, interesting. How frequently do you advise monitoring these levels to accurately determine their typical range? And I just have to try and pronounce your name Volod Resnichenko. What a cool name. Volod, interesting. I'm a big fan of like two syllable first name. I don't know, today. All right. So Volod Resnichenko.

• 40:40Andrew D. Huberman?

  Thank you for this question and the opportunity to try and pronounce your name. So hormone levels. I think a good thing to do is in the absence of any apparent or suspected endocrine dysfunction. Right? So we're talking about you feel pretty good. You're wondering if you're good under the, if I say good under the hood, that just sounds like weird. It rhymes. So if you're feeling pretty good, I recommend getting your hormone levels checked once. If you can, if you're still in your teens, in your late teens, after you've gone through puberty to establish a sort of baseline. Most people won't do that because it's too late. I didn't do that. Once in your mid twenties. Again, we're talking about no suspected or apparent endocrine dysfunction. Okay.

• 41:25Andrew D. Huberman?

  In your mid twenties, you have a baseline, something to compare to when you were in your, say, 18 to 20. And again, and when you're 25, that would be ideal. And then again, I would say when you're 30 and then start once a year, starting when you are 40 or older. I think that just, you know, just logically, I would love to know what my hormone levels were when I was 25, when I was 30.

• 41:53Andrew D. Huberman?

  Maybe when I was, yeah, when I was 18, 25, 30, 35. And actually 35 is when I got my first blood, blood draw for just getting a look under the hood. Like what's there? What, what, what are my estrogen levels? What are my testosterone levels? What are my growth hormone levels? This kind of thing. And then, once you're 40 and older, I think, once a year, minimum, and I realize that some people out there are gonna say, "Well, that's ridiculous. What are you gonna do with that information?" Well, you're gonna do a lot with that information. You're gonna figure out whether or not your LDL cholesterol is in healthy range. You're gonna figure out whether or not your ALT is in the healthy range. You're gonna figure out whether or not your ApoB is in healthy range. You're gonna figure out a lot more than just whether or not your testosterone is, you know, 400, 600,

• 42:35Andrew D. Huberman?

  800, or 1200. And I think we also need to be careful about overinterpreting results of hormones, because a lot of it has to do with the ratio of testosterone to estrogen, or the ratio of free testosterone to testosterone, both in men and women. So, for instance, if your testosterone level is 900, but your free testosterone level is 2, well, then you have a problem. Whereas if your total testosterone level is 500 or 600, but your free testosterone level is, you know, 15, well, then you're probably doing pretty well. So, I would say, getting your hormone levels checked once a year after age 40, and prior to that, once

• 43:18Andrew D. Huberman?

  every three to five years, starting at about age 18, would be ideal. But most people don't do that. They either don't have the disposable income. I certainly didn't when I was 18, 20, 25. And at that time, it was really hard to get that measured unless you had a clinical problem. Now, if anyone has a clinical problem that they suspect, or is real, then obviously, more testing. I think great sources for endocrine profiling are things like Inside Tracker. Full disclosure, they are a sponsor of the podcast, but they do an excellent job. They'll even come to your house. The phlegm bottomus will come to your house if you want, or you can go to a clinic, so they make it all very easy. But there are other sources as well, right? I'll never make these AMAs or anything else about specific companies for its own sake. I just think Inside Tracker does a great job. There are a number of clinics,

• 44:02Andrew D. Huberman?

  like Merrick Health and others, online clinics, that will do that, but it's part of a more comprehensive package of agreeing to work with them. At least, that's how I understand it. I hope I didn't get that wrong. But check and see. Nowadays, it's pretty easy to find ways to get your hormones checked. But I would suggest that the following things, at least, be on there. Growth hormone, or IGF-1, rather, IGF-1, testosterone, estrogen, this is true for women and men, by the way, so IGF-1, testosterone, estrogen, they'll show up as estradiol on there. Free testosterone, dihydrotestosterone, cortisol, keep in mind, morning cortisol is always elevated relative to afternoon cortisol.

• 44:42Andrew D. Huberman?

  It will be impacted by food, so you want to go in fasted in the morning, ideally get this done early. Your creatinine levels, which by the way will be elevated if you're taking creatine or you're exercising hard. Your doctor will say your creatinine levels are elevated and you say, well, great, well, my creatine intake is elevated too, so, you know, take that. It's not going to be a problem necessarily. Do check with your doctor. LDL cholesterol, ApoB, and there are probably a few others that would be good to have in there for men and women, sex hormone binding globulin, SHBG, and for women especially, progesterone and prolactin, and any of the progestins are going to be important.

• 45:25Andrew D. Huberman?

  And of course, for women, the trick is going to be when you get your blood taken with respect to your hormone cycle, your ovulatory cycle, and to try and make that at least consistent from test to test, not necessarily having to go in both during the follicular and the luteal phase of your cycle, but always going in during, you know, mid follicular or mid luteal, and that can be challenging to do, perhaps, but that's going to be important because of course those are widely fluctuating levels across the cycle. But unless you're really obsessed with your hormone levels and analyzing them, taking them at multiple times throughout your menstrual cycle, probably not necessary unless you're starting to think about conceiving or there's some issue, PCOS or other issue.

• 46:08Andrew D. Huberman?

  Okay, I find that I need to do NSDR after working out. Any thoughts on this? Yes, well, first of all, I'm glad you're using NSDR as your cost tool, known to replenish mental and physical vigor, works oh so well. I think it's great. I think it probably is accelerating your recovery. I think this tells me that you're probably working out really hard and hopefully not too long. If you find that you work out in the morning and then you're really, really sleepy in the afternoon and the next day, you might be working out too long or too hard. So maybe ratchet back the intensity a little bit or the duration. It's amazing how great we can feel when we work out to like eighty to ninety percent of our maximum output

• 46:49Andrew D. Huberman?

  um in duration. We did this the other day. We, you know, the, you know, we, we went out for a little jog, run, bounding, skipping, uh, jumping jack thing and stopped at like eighty to ninety percent of maximum. And then went about the rest of the day and evening feeling great. If you do this, you know, consistently, you'll find you have more energy and there's actually a lot of solid physiology and physics to support why that is as opposed to if you go to the gym and you do every set to failure or even every exercise you include one set to failure and you're grinding out four straps or you're, I don't know what kind of exercise you're doing or you're running more and more distance each day or with more intensity, you know, it, it's understandable how one gets kind of

• 47:32Andrew D. Huberman?

  um drawn to or addicted to that burn or the effort, but keep in mind that is stress. You're, you're stressing the body to produce a certain kind of adaptation, either endurance or strength or hypertrophy or et cetera adaptation. So, you know, there's, there's real beauty in learning to love working out hard, but to leaving the gym or ending the run with ten to twenty percent of the gas in the tank. And knowing that you can come back and do more and you actually kind of want to do more. There's, it increases vigor as opposed to taking yourself over that cliff even a slight ten to twenty percent and then finding that you're, you're kind of depleted. And this is something that we don't hear enough about because we, uh, most people that are into fitness are into pushing themselves.

• 48:14Andrew D. Huberman?

  It's also true for work. I think some of the best advice I ever got in the professional landscape was when I was a graduate student at UC Berkeley and an excellent neurologist by the name of Bob Knight said, the key is to figure out how much can you work each day consistently? If that's four hours a day, fine. If that's eight hours a day, fine. We're talking with weekend breaks because that was in the era of weekend breaks. Maybe a weekend every once in a while where you have a deadline. But by thinking about what you personally can really do consistently while maintaining sleep and mental health and physical health, you're going to go a lot further. Then doing like, for instance, what I did, which is being a maniac and working hundred hour weeks as a graduate student and then ending up sick four times a year and missing out on a bunch of days when I could have been in lab. So these days I try and get

• 48:56Andrew D. Huberman?

  as much focused work done as possible, but try and make that as consistent as possible, if not from every day to the next over time, you know, figure out what those averages are and don't be ashamed of those averages. I would say declare those averages to people so they know what to expect. And the fact that you can do more does not necessarily mean that you should do more because I think one of the best pieces of advice I ever got in the world of fitness is more important than training hard, more important than doing any particular exercises, more important than anything is to not get hurt. Because if you get hurt, you can't train. So I love that you're doing NSDR after training. I love that you're making that part of your practice, but maybe also throttle back a little bit because you said I have to do it after training. Maybe throttle back a

• 49:39Andrew D. Huberman?

  little bit on the duration or intensity of exercise and see how you feel. What can we do to optimize the function of our gut-brain axis? That's very simple. Get enough sleep in addition to that. Avoid excessive intake of antibiotics, but if your doctor prescribes them, take them. I am a believer in antibiotics. Okay. Before the internet jumps on me, I'm not anti antibiotic. I'm not anti antibiotic. I'm always want to say that. I'm not anti antibiotic. I am not pro antibiotic, but I am pro probiotics. I'm probiotic. So I think you should ingest one to four servings of low sugar fermented foods per day. So sauerkraut, kimchi, natto, or kefir, or otherwise, whatever you like and fits with your nutrition

• 50:23Andrew D. Huberman?

  preferences and plan. I think it's also very important that you don't overuse antiseptics like antiseptic mouthwashes and hand rinses and all that stuff. This was all discussed on a podcast episode I did with Dr. Justin Sonnenberg on the Hubert Lab Podcast, which is just to say that Justin, who's a professor at Stanford and is amazing, even said that he lets his kids eat lunch when they've been playing outside without washing their hands before eating lunch because he wants the probiotic. Makeup of their gut to be diverse, including from outside. Now, I'm presuming that's not a public park. I'm assuming it's their yard. So we're not talking about gross stuff being on their hands. We're talking about a little dirt here and there. Turns out owning a pet increases the diversity of your microbiome. Lots of things like that. I mean, you don't want to go around,

• 51:08Andrew D. Huberman?

  you know, licking people's pets. It's okay to let them lick you, depending on what your preferences are, but don't lick them. But when you interact with people, you shake their hands, your pets, you're increasing the diversity of your microbiome. When you eat low sugar fermented foods, you want to make sure also you get enough fiber, both prebiotic and probiotic fibers of fruits and vegetables. The fiber debate for me just like makes me roll my eyes. I mean, it's so clear that fiber is good for us, for gut motility and for offsetting cancers of the gut. I mean, I realize there are the people out there who are really into elimination diets where they just only eat meat, but I mean, there's just so much good data on fiber, especially

• 51:49Andrew D. Huberman?

  from fibrous vegetables. It just seems like what? Yes. I mean, it's almost silly that we have the debate, frankly, but I'm sure someone out there who's pure carnivore will be shouting, but guess what? You're shouting and you're constipated.

• 52:04Andrew D. Huberman?

  Last question.

• 52:08Andrew D. Huberman?

  Regarding the subject on tongue cleaning from the oral health episode, can you please share a bit on brushing tongue, scraping tongue, and generally how best to clean the tongue?

• 52:20Andrew D. Huberman?

  So tongue cleaning came up on the oral health episode. I talked to four different dentists and a periodontist in preparation for that episode. Almost all of them remarkably, extraordinarily converged on the same advice, except for some slight deviations around frequency of flossing. It's kind of cool, right? A field where almost everybody seems to agree. I realize that isn't the hugest sample size, but I picked them from diverse locations, backgrounds, trainings, etc.

• 52:47Andrew D. Huberman?

  Every one of them said brush and floss your teeth. Every one of them said antiseptic alcohol-based mouthwashes are bad. And every single one of them said that brushing your teeth before sleep is especially important because at night you produce less saliva and you want to be able to re-mineralize your teeth. That is, fill in cavities that are starting to form while you sleep. So brush your teeth, floss ideally as well before sleep, but at least brush. And of course, in the morning too, for everyone's sake. But if we're talking about tongue brushing and scraping, it was clear that tongue scraping was advised if done correctly, okay? Because there are certain bacteria that grow on the tongue that you don't want there. And that scraping can help with the turnover of healthy bacteria there in addition to removing some of the bad bacteria.

• 53:33Andrew D. Huberman?

  But that most people scrape their tongue too hard.

• 53:38Andrew D. Huberman?

  And rather, it would be wise to brush your tongue gently with a soft toothbrush. And by the way, you should also use a soft brush for your teeth, but not the same one that you use for tongue brushing. So the takeaway that I was told and makes a lot of sense to me based on what I know now about the biology, physiology and care of the mouth is that you want to use a different soft toothbrush to brush your tongue than the soft brush that you use to brush your teeth. And that you do not need to use anything on it, but if you wanted to put a little bit of salt and baking soda, that is perfectly fine. A lot of people wonder whether or not baking soda scrapes the enamel off the teeth. It actually is low on the abrasion scale dentists have, believe it or not,

• 54:19Andrew D. Huberman?

  an abrasion scale with a list of things of how much enamel it scrapes off at a given pressure. These dentists have done their work. It's really, really cool. I can't say I always liked dentists. I didn't like going to dentists. They always seemed like nice people. But now I have newfound respect for dentists. They really care about their craft. And oral health has been kind of pushed to the backseat of the different aspects of health. I consider it one of the major pillars of mental health and physical health because taking care of your teeth, your gums, your mouth, including your oral microbiome is critical for cardiovascular health. It's critical for brain health. One of the bad bacteria, streptococcus mutans that can proliferate in the mouth, especially after sugary, eating sugary foods, can make it through the blood brain barrier. And maybe it's thought one of the causes of dementia can disrupt your neurons.

• 55:04Andrew D. Huberman?

  Your brain and body is a system, everything's talking to everything else. And so, yeah, brush your tongue, but use a separate soft brush to do that and replace it every few weeks to months that can, I suppose, get expensive, but probably not as expensive as some of the other health issues that were just described. So I appreciate that question. We didn't talk about oil pulling on the podcast. A lot of people asked about that. Some people like to swish oil and then spit it out as a way that's oil pulling for oral health. And all the dentists I spoke to said, nah, not big fans of oil pulling, but none of them said it would be particularly bad. But, you know, so if you enjoy it or you think it works for you, great. But none of them really pointed to any clear evidence that it was going to be beneficial.

• 55:50Andrew D. Huberman?

  So I was told that was the last question and we are coming up on the hour. Again, I want to thank everybody for joining this AMA, doing this from Australia, Sydney, Australia. What's interesting down here is because we are below the equator, everything is reversed, right? So this was actually, it's being presented to you upside. I was, I'm actually upside down, but they turned the camera so I would appear right side up to you. I also, when I'm down here, I drink my AG1. Normally I swish it counterclockwise, but I notice here reflexively, I'm swishing it clockwise. So anyway, lots of interesting stuff going on. We'll talk about how that all works. It's not through the vestibular ocular reflex, it turns out, but maybe on a future episode of the podcast about the relationship between location relative to the equator and neural functioning. And I'm just kidding.

• 56:35Andrew D. Huberman?

  But what I'm not kidding about is they appreciate that you tuned in. And last, but certainly not least, thank you for your interest in science.