How to Control Your Metabolism by Thyroid & Growth Hormone | Huberman Lab Essentials

welcome to hubman Labb Essentials where we revisit past episodes for the most potent and actionable science-based tools for mental health physical health and performance I'm Andrew huberman and I'm a professor of neurobiology and Opthalmology at Stanford school of medicine this podcast is separate from my teaching and research roles at Stanford it is however part of my desire and effort to bring zero cost to Consumer information about science and science related tools to the general public today we are going to talk about two hormones thyroid hormone and its related Pathways and growth hormone and its related Pathways which arguably are the two hormones and two systems in the body that are most significant for setting your overall level of metabolism so metabolism is the consumption of energy not necessarily eating but it's the use of energy in the cells of the Body for growth of tissues for repair of tissues and also just for day-to-day maintenance of function these two hormones thyroid hormone and growth hormone we think of as related to metabolism of things in the body keeping body fat low and keeping muscles strong and tendons strong and repairing themselves Etc but they are also key for brain function for the ability to maintain cognitive function throughout the lifespan so the big theme I'd like to introduce is that metabolism isn't just about losing weight but having a high metabolism provided it's not too high is great it means that you will have more lean tissue more bone and muscle and less adapost tissue fat and we know that that's healthy there are neurons in your brain in an area called the hypothalamus which is just means it's below the thalamus hypo it sits at the base of your brain in the front it's part of the forebrain so it's more or less above the roof of your mouth maybe about a centimeter or so and then about a centimeter forward in most people and neurons in the hypothalamus release hormones that are called releasing hormones so anytime you hear releasing chances are those are neurons that are in your brain and they extend little wires we call axons into your pituitary and the pituitary releases a bunch of hormones into the bloodstream and the pituitary releases things that most often have the name of stimulating hormone because they stimulate or organs so in keeping with the theme of thyroid hormone you have thyroid releasing hor hormone in the brain tells the pituitary to release thyroid stimulating hormone and then the thyroid which we'll talk about in a moment releases thyroid hormones the thyroid is a little butterfly shaped gland that's right around the atoms apple and it's got four little bumps behind it called the parathyroid gland and it releases two hormones into the blood to stimulate different tissues and their metabolism and those hormones are called T4 and T3 so if this is already sounding like a lot of information it's really easy I promise releasing hormone comes from the brain stimulating hormone comes from the pituitary and in this case we're talking about the thyroid binding up that stimulating hormone and saying oh I need to release something and it releases T4 and T3 and guess what you can basically forget about T4 T4 it's not completely inactive it has some roles but T3 is the one that's more or less active now what does thyroid hormone do the main role of thyroid hormone of T3 is is to promote metabolism and that doesn't just mean the consumption of energy it means the utilization of energy including the buildup of tissues so it acts on all sorts of Target tissues in the body it acts on muscle it acts on the liver it acts on the cartilage it acts on the bone it's involved in taking fats and breaking them down into fatty acids and converting those into ATP which is an important thing for cells to use energy it's also involved in taking sugars and turning those into energy and yes it goes to atopos tissue to Fat we have different kinds of fat that we'll talk about today but it goes to white fat and it liberates or helps liberate some of the fats from those fat cells and use them for energy and this is why higher thyroid is associated with leaner bodies lower thyroid is associated with llean bodies one thing that's absolutely key and is actionable we're right there already in discussing tools is iodine iodine is most common in sea salt in kelp and in seaweed and most people can get enough iodine from the food they eat Andor the table salt they consume almost all table salt from all over the world regardless of where you are contains iodine the thyroid needs iodine in order to produce thyroid hormone iodine combines with an amino acid that we've talked about before called el tyrosine el tyrosine comes from meat from nuts there are some plant-based sources as well it is the precursor to dopamine but in the thyroid iodine combines or works with El tyrosine to produce T3 and T4 the thyroid hormone so you absolutely need sufficient iodine you need sufficient El tyrosine and then you also need something else which is called selenium selenium is important in order for thyroid hormone to be made because of the way that it allows El tyrosine and iodine to interact and the thing is most people aren't getting enough selenium because they don't eat foods that are high in selenium now the how much selenium you need will depend on where you live it actually varies country by country some countries I found uh say that you should get 100 microgram some say 200 some say 155 the average was about about 155 micrograms the countries I looked at people who are trying to increase thyroid levels might want to uh consume more selenium and if you consume a vitamin of course you want to make sure um if it has selenium that you're not overdoing it by consuming a lot of selenium rich foods either Brazil nuts are the heavyweight champion of foods to get selenium from it has very high concentrations of selenium in just six or eight uh Brazil nuts contain something like 550 micrograms of selenium it's also present in fish ham of all things um contains a lot of selenium uh for whatever reason pork does I'm not a big consumer of pork um beef has some selenium but what's interesting if you look at the sources you know pork beef turkey chicken cottage cheese eggs brown rice they what you want to understand is that they they have something like 30 to 50 micrograms of selenium so if you're not eating Brazil nuts and I'm guessing most people aren't then and you're not eating a lot of uh animal-based foods which I know many of you aren't then you're probably not getting enough selenium and again you can have these uh levels measured or you can just check what you're consuming um and figure out whether or not you're re meeting the ration that you need in order to get healthy levels of thyroid I also want to mention that for children the daily requirements of selenium are much lower as low as you know 30 or 40 micrograms for kids uh 14 years or younger and again that's micrograms not milligrams so again look into what you need but if you're somebody who's interested in keeping thyroid function healthy and productive then you certainly want to make sure you're getting enough iodine you're getting enough selenium and you're getting enough L tyrosine and it's interesting when you start looking at the various Foods especially highly processed foods then you start to realize that perhaps many people maybe you are not if you're curious how thyroid actually increases metabolism allows you to eat more Etc it relates to something we covered last issue which is glucose remember when you eat something blood sugar goes up insulin is secreted from the pancreas and it makes sure that blood glucose doesn't go too high which can damage tissues or too low which can make you hypoglycemic thyroid increases glucose uptake by various tissues in particular muscle and bone it actually can increase bone mineral density which is a really good thing as you get older when I say older I mean basically 30 and older you the the reason you can recover more quickly from injuries if you have a healthy thyroid and healthy thyroid Pathways is because you can consume energy that energy is diverted toward bone repair and muscle repair and cartilage repair and so the way it does this again is by increasing ATP but the whole idea here is that iodine selenium El tyrosine allow thyroid to be a healthy level so that thyroid then can take glucose in the blood and divert it to tissues for it to be used used in particular your brain and that's why the ability of your brain to use glucose or ketones for that matter is going to be aided by having healthy thyroid so do the things take the things eat the things that are going to allow you to have healthy levels of thyroid hormone if you're concerned about having excessively high or excessively low levels of thyroid hormone absolutely uh look up what the symptoms are talk to your physician um and there are a number of good treatments I didn't talk about prescription drugs that can prove symptoms related to hypo or hyper thyroid of course they have synthesized thyroid um so if you don't make enough thyroid you can take thyroid it's by prescription if you take have too much thyroid sometimes they'll take out the thyroid gland or they can administer drugs that will either block receptors or will interfere with some of the pathways from the brain uh to the pituitary or from the pituitary to the thyroid in order to adjust thyroid hormone that way so there are the the big guns uh in terms of the treatments for different thyroid disorders um but we're not talking about thyroid disorders we're talking about how to get and maintain thyroid levels in healthy ranges and some straightforward ways to do that through diet and supplementation next we're going to talk about growth hormone growth hormone is a pretty straightforward one for you to understand now because it follows the exact same logic as thyroid hormone in fact their functions are so closely overlapping that you're probably going to think why do you have these two systems so just very briefly G growth hormone releasing hormone so remember releasing means it comes from the brain comes from the brain and tells the pituitary to release growth hormone and then growth hormone is released into the bloodstream where it goes and acts on a ton of tissues muscle ligaments bone fat Etc to increase metabolism it sounds just like thyroid hormone and they do work in parallel and that's why we've lumped them together in the same episode they increase metabolism and repair and growth of tissues today we're going to talk about the things that anyone can do to increase growth hormone and there are reasons why certain people would want to do that people that make normal quote unquote levels of growth hormone might want to do that as they age because during puberty and development the pituitary is churning out tons of growth hormone it's responsible for the growth not surprising of the body and all its features height just being one of those and so as we age we make less growth hormone and that is one of the reasons why we recover more slowly from injuries it's one of the reasons why we accumulate body fat and it's one of the reasons why our metabolism slows and so growth hormone replacement therapy has been tremendously popular in the last 20 years which is not to say it doesn't carry its problems it does here's one of the major problems with injecting growth hormone not saying people shouldn't do this if the doctor has approved it or it's um in keeping with their particular life goals but growth hormone if it's in levels that are too high will cause growth of all tissues so not just muscle not just reduction of in body fat by metabolizing um you know by allowing uh fatty acids to be pulled out of storage and used for ATP but it will also cause increase in growth of the heart and the lungs and the liver and the spleen and so this is the concern with abuse of growth hormone so we're not going to be talking about abuse of growth hormone we will however talk about tools that anyone can use to increase levels of growth hormones some of them are behavioral some of them are supplement based and some of them interact with behaviors and supplements and what's cool about the discussion about growth hormone is that the tools that exist out there to increase growth hormone are very actionable there are things that can increase growth hormone three four 500% or more and even though that's a short-lived increase they can have very powerful effects on metabolism and on repair of tissues so let's talk about those as always I want to emphasize talk to a doctor before you do anything including remove any treatments growth hormone is released every night when you go to sleep and it's released in the early part of sleep during so-called slow wave sleep so the two conditions that have to be met in order for growth hormone to be secreted regularly for tissue repair Etc are you need to get into slow wave sleep the so-called deep sleep and you need blood insulin and glucose to be relatively low so eating within 2 hours of going to sleep is going to suppress growth hormone release that's very clear so what is special about this early phase of sleep what in particular about slow wave deep sleep allows the pituitary to release growth hormone so the answer is it's Delta wave activity in the brain delta waves are these big giant waves of activity in the brain that correlate with slow wave sleep as opposed to faster waves of activity that associate with rapid eye movement sleep it's the delta waves of activity these sweeping big waves of activity in the neurons that stimulate the brain to stimulate the pituitary because once you understand that then you have something to Anchor to in terms of thinking what are the things I can in waking that will allow me to release more growth hormone which for most people is going to be a good thing now the Delta wave activity and the slow wave activity in the brain being very important for growth hormone release and growth hormone release being so important for metabolic functions and peeling away unwanted body fat and repairing tissues Etc forces us to ask well what other things can we do in waking in order to increase growth hormone release so let's start with the ones that have a uh potentially big effect but are a little bit harder to access and for that I want to point toward a book which is really kind of interesting it's not focused on growth hormone but the book is called altered traits this is the book um it's an excellent book um altered traits by Goldman and Davidson science reveals how meditation changes your mind brain and body very interesting book um for those of you that are interested in meditation and perhaps those of you who are not but are considering it they what they talk about in this book is the fact that meditation has two separate lines of effects one of those lines of effects are things that change your state so you're stressed you sit down you meditate and you relax and you go into a particular State the other are the changes that occur over time and those are changes in trait so personality can actually change with long bouts of of of TM meditation or repeated meditation in any case the re we're talking about altered traits today is because certain types of meditation can get people's brains into states that very closely mimic slow wave sleep so what this means is for for people that are interested in increasing growth hormone a meditation practice that allows you to get into these slow wave delta type frequency uh activity in the brain may be very beneficial because as I mentioned before that's what's gating growth hormone release it's not just a circadian phenomenon it's actually controlled by these uh brain waves now let's move to the things that one can do that have been shown to have what's let's just be honest pretty enormous effects on growth hormone release in waking and these are things that are very actionable one of the things that can have a dramatic effect on levels of growth hormone release in waking as well as in sleep the following night is ex exercise there are hundreds if not thousands of studies measuring growth hormone both during or sometimes after exercise or the following night and the conclusion that one takes away from all of these is that exercise has to be of particular duration and intensity in order to get growth hormone release so first I'm just going to tell you what I found to be the maximum amount of growth hormone release as it relates to a particular form of exercise the particular form of exercise is either weight training or it can be endurance training but the endurance training and the weight training actually have to be limited to about 60 Minutes not much longer a proper warm-up seems to accelerate the release of growth hormone once the hard work phase starts so 10 minutes of warmup or so was the number that I extracted from all these studies and when you say warm up it doesn't mean just warm up the limb and tissues that you're going to use so you don't get injured actually warm the body getting the body warm as a warmup seems to be important because temperature of the body seems to be an important condition or prerequisite for certain patterns of exercise to maximize growth hormone release so if it's weightbearing exercise it would be getting close to that um final repetitions where you can't complete them but not pushing through those or even going to failure but getting close leads to anywhere from 300 to 500% increases resting growth hormone levels and 300 to 500% increases in growth hormone the following night when you go to sleep which is incredible one of the other conditions that seemed to be important again was to have relatively low blood glucose so probably not eating too close to exercise or not ingesting a lot of sugars during the exercise that was supported by the fact that ingestion of a sport drink that contains caloric sugar immediately flatlined the growth hormone levels so really interesting relationship between insulin glucose and growth hormone and then the other interesting thing was that even after the exercise taking body temperature back down to normal levels relatively quickly seemed to be associated with these big spikes in growth hormone otherwise what would happen is you get these big spikes in growth hormone but if the exercise went too long or if body temperature remained too high for too long then you didn't get the second increase in growth hormone the following night let's talk about supplements so this has been known about for some time but um Arginine the amino acid arginine can increase growth hormone levels substantially the levels and the amounts of gr of arginine required to get big growth hormone release increases is pretty substantial so some people will take Arginine before bedtime some people will take it before exercise the prerequisite again is low blood glucose blood glucose is high it's going to quash the effect the amounts of arginine that people take are anywhere from 3 G to 10 gram or sometimes even more although this is definitely a case of more is not better there's a threshold at which growth hormone release is actually blunted by taking more than n grams of arginine now nine gram of arginine orally is a lot of pills it's at minimum nine pills and it can cause some GI disturbance right people can feel nauseous some people will throw it up what's interesting however is that whether or not it's by mouth or by vein taking Arginine can dramatically increase growth hormone release 400 to 600% above baselines these are huge increases in growth hormone now here is something really important and interesting to note which is that increasing Arginine levels with the specific goal of increasing growth hormone release can actually shortcircuit the effects of exercise on growth hormone several studies I looked at looked at the interaction of taking Arginine and the exercise or just the Arginine or just the exercise alone and so you don't uh unfortunately if growth hormone increases your goal you don't unfortunately get to increase growth hormone 800% by taking Arginine and exercising it always seems to be clamped at about 3 100 to 500% increases so hopefully that's clear one thing that's particularly interesting to me as somebody who's in his 40s is that it's actually between ages 30 and 40 that the amount of growth hormone that you release each night is reduced by two to threefold and since everybody goes through this age related decline very dramatically it seems to me that the things that we're supposed to be doing anyway like exercising like trying not to eat too close to bedtime trying to optimize sleep all of these are wonderful tools that we should um be pursuing and perhaps using and they can actually offset the two to threefold decrease right if we're talking about a two to threefold decrease for people there in their 30s and 40s and then we're talking about increases from exercise or from maybe from supplementation but certainly from exercise of 300 to 500% well then all of a sudden we're in a position to actually offset the age related decline in growth hormone completely just through behaviors and I think that's quite interesting and quite powerful now I'd like to discuss a way that anyone can increase their levels of growth hormone dramatically and when I say dramatically I mean dramatically I'll get to the numbers in a couple minutes but we have to remember how growth hormone is released in the first place remember it all starts in the brain in the hypothalamus the hypothalamus is a brain area that controls things like sexual behavior temperature regulation circadian Behavior meaning when you want to be awake when you want to be asleep aggression all of that there are other brain areas involved too but it has a rich collection of different neurons involved in all these very basic functions now as we talked about the releasing hormones the growth hormone releasing hormone comes from neurons in the hypothalamus those then communicate with the pituitary and the pituitary releases growth hormone and then the growth hormone acts on all these different tissues muscle liver cartilage Etc body fat makes them use energy that's why you lose body fat when growth hormone levels are high makes you grow muscle strengthens bones Etc now one of the things that has a profound effect on growth hormone levels growth hormone release is temperature now the data on this are very strong and the data come from both animal studies and human studies and if you're guessing which direction this is is going to go you can probably imagine that making animals or people warmer is the way to go if you want to increase growth hormone now anytime you're going to increase temperature of yourself or anyone else or an animal it is risky I want to be really clear about this not everyone should engage in the behaviors I'm about to describe but and I should just say the reason it's risky is it doesn't take much of a temperature increase in the brain to cook the brain to cook Nur neurons and after that point neurons can't come back and people can die from hyperthermia however there are really strong data pointing to the fact that sauna AKA deliberate hypothermia not too high however that sauna can increase the release of growth hormone and other hormones and what's so dramatic about this literature is the size of the effects that are reported entering environments with where it's very hot for short periods of time anywhere from 20 minutes to 30 minutes where the temperature is 80° C to 100° C has been shown to increase growth hormone release 16 fold that's right 16-fold that's 1, 1600% now there are also effects on other hormones prolactin cortisol Etc so the pattern that was described in this study there have been many studies now now um endocrine effects of repa sauna um were were done in 17 humans they actually had to do this three days in a row and the pattern was to get into the sauna for 20 minutes followed by 30 minutes of cooling followed by 20 minutes sauna again led to a five-fold increas in growth hormone and then by doing that day after day after day on the third day you would see these huge increases of like 16 fold up to 16 fold but these increases in growth hormone are tremendous and what they probably stem from are increased activity of neurons within the hypothalamus that stimulate growth hormone release from the pituitary and that's probably because the growth hormone releasing hormone neurons in the hypothalamus sit very closely and may even be intermixed with some of the neurons in the hypothalamus that regulate heat and body temperature remember metabolism is in part a heat it's like a furnace of how much energy you're consuming in using for building or for um energy usage purposes so sauna can be very very interesting and again it's 20 minutes 30 minute cooling 20 minutes again um proceed with Extreme Caution but nonetheless these are pretty extreme effects in terms of their abilities to increase growth hormone levels there's a kind of new area that's developing now that I think deserves our attention not because I'm encouraging it but because it is happening and those are peptides so these days you hear a lot about peptides I'd like to clarify a little bit about what peptides are peptides is a really huge category of biological compounds peptides are just strings of amino acids right so we've talked about Al tyrosine Arginine ornithine those are amino acids those are individual amino acids and those are put together into little small peptides or they're what they're called polypeptides which are just longer peptides turns out that for any substance like growth hormone or growth hormone releasing hormone it's made up of different amino acids and different sequences just like your genes are made up of AG A's and G's and C's and T's nucleotides in different sequences it's like a recipe peptides tend to be short sequences of amino acids that resemble a hormone enough or resemble some other peptide enough that it can lead to the similar or same effects when you inject them so for example we make growth hormon releasing hormone from our brain which stimulates growth hormone from the pituitary but people now will take things like Calin s e r m o r e l i n sermorelin which is not the entire peptide sequence of growth hormone releasing hormone but it's a subset of those then that stimulates the release of growth hormone from the pituitary so this is not taking growth hormone this is taking the stimulating hormone or what's often called a secretagogue or a mimic all right it causes a a secretion of the hormone that one wants sir Morin is prescription do they work yes do they shut down your natural production of growth hormone releasing hormone well there the answer is yes but some of these peptides actually have the effect of changing gene expression because as you recall growth hormone in big uh big increases in growth hormone that are short-lived like s or I you know I should say exercise or Arginine or sauna it seems like has these huge effects those are transient but when one is injecting over and over a constant level you can put into action gene expression programs that can be longlived and let's say you have a particular tumor in the body tumors will grow when they see growth hormone even if it that tumor is unhealthy for you right you've got growth of tissues all over the body so again not promoting their use but they're definitely out there and so now if you hear about them or someone's talking to you about them now hopefully you have a better understanding about their underlying biology and you can think rationally about whether or not they are the right decision for you okay once again covered an enormous amount of material hopefully now you understand thyroid hormone and what it does and a little bit about its mechanism or maybe a lot and growth hormone and what it does and how both of them take care of our metabolism they dictate how many nutrients we can eat and make use of they can pull from body fat stores repair muscle repair cartilage they really are incredible compounds and they are actionable they're things that we can do like getting that early phase of sleep perhaps supplementing with Arginine maybe not hopefully getting adequate exercise warming up properly not making the exercise too long or too intense will help maybe sauna or things like it you know deliberate safe hyperthermia with the emphasis on safe might be things that are of use so now hopefully you understand not just thyroid and growth hormone but logic that underlies thyroid hormone growth hormone estrogen testosterone why we eat why we stop eating chosy gin if these names don't mean anything to you then perhaps go back and listen to those episodes but regardless I hope that you come away from this with a deeper understanding about these hormones which are so powerful in controlling the way our brain functions and the interplay between the brain and hormones because it is really a bidirectional conversation the brain is telling the body what hormones to make the hormones are influencing all the tissues of the body but also telling the brain whether or not to eat more or grow more or think more Etc so I really appreciate your time and attention if you like this podcast and you're finding it useful please recommend it to other people and last but not least I thank you for your time and attention and above all for your interest in science [Music]