How to Control Your Metabolism by Thyroid & Growth Hormone

00:00:00.000 | - Welcome to Huberman Lab Essentials,

00:00:02.320 | where we revisit past episodes

00:00:04.380 | for the most potent and actionable science-based tools

00:00:07.560 | for mental health, physical health, and performance.

00:00:10.320 | I'm Andrew Huberman,

00:00:12.880 | and I'm a professor of neurobiology and ophthalmology

00:00:15.880 | at Stanford School of Medicine.

00:00:17.980 | This podcast is separate

00:00:19.120 | from my teaching and research roles at Stanford.

00:00:21.380 | It is, however, part of my desire and effort

00:00:23.380 | to bring zero cost to consumer information

00:00:25.440 | about science and science-related tools

00:00:27.680 | to the general public.

00:00:28.840 | Today, we are going to talk about two hormones,

00:00:31.920 | thyroid hormone and its related pathways,

00:00:35.120 | and growth hormone and its related pathways,

00:00:38.420 | which arguably are the two hormones

00:00:41.200 | and two systems in the body that are most significant

00:00:44.740 | for setting your overall level of metabolism.

00:00:47.720 | So metabolism is the consumption of energy,

00:00:50.840 | not necessarily eating,

00:00:52.200 | but it's the use of energy in the cells of the body

00:00:56.440 | for growth of tissues, for repair of tissues,

00:01:00.000 | and also just for day-to-day maintenance of function.

00:01:04.000 | These two hormones, thyroid hormone and growth hormone,

00:01:07.040 | we think of as related to metabolism of things in the body,

00:01:10.280 | keeping body fat low and keeping muscles strong

00:01:13.320 | and tendons strong and repairing themselves, et cetera,

00:01:16.160 | but they are also key for brain function,

00:01:19.360 | for the ability to maintain cognitive function

00:01:21.580 | throughout the lifespan.

00:01:23.160 | So the big theme I'd like to introduce

00:01:26.340 | is that metabolism isn't just about losing weight,

00:01:30.740 | but having a high metabolism,

00:01:32.280 | provided it's not too high, is great.

00:01:34.000 | It means that you will have more lean tissue,

00:01:35.960 | more bone and muscle and less adipose tissue, fat,

00:01:39.520 | and we know that that's healthy.

00:01:41.060 | There are neurons in your brain

00:01:42.520 | in an area called the hypothalamus,

00:01:45.000 | which just means it's below the thalamus, hypo.

00:01:47.160 | It sits at the base of your brain in the front,

00:01:49.000 | it's part of the forebrain.

00:01:50.320 | So it's more or less above the roof of your mouth,

00:01:52.160 | maybe about a centimeter or so,

00:01:53.960 | and then about a centimeter forward in most people.

00:01:57.020 | And neurons in the hypothalamus release hormones

00:02:02.020 | that are called releasing hormones.

00:02:05.180 | So anytime you hear releasing,

00:02:07.180 | chances are those are neurons that are in your brain

00:02:10.540 | and they extend little wires,

00:02:11.860 | we call axons into your pituitary,

00:02:13.980 | and the pituitary releases a bunch of hormones

00:02:16.820 | into the bloodstream,

00:02:17.980 | and the pituitary releases things

00:02:19.820 | that most often have the name of stimulating hormone

00:02:22.980 | because they stimulate organs.

00:02:25.120 | So in keeping with the theme of thyroid hormone,

00:02:27.860 | you have thyroid releasing hormone in the brain,

00:02:30.960 | tells the pituitary to release thyroid stimulating hormone,

00:02:35.060 | and then the thyroid, which we'll talk about in a moment,

00:02:37.980 | releases thyroid hormones.

00:02:39.620 | And the thyroid is a little butterfly shaped gland

00:02:42.860 | that's right around the Adam's apple,

00:02:44.920 | and it's got four little bumps behind it

00:02:46.880 | called the parathyroid gland,

00:02:48.340 | and it releases two hormones into the blood

00:02:51.820 | to stimulate different tissues and their metabolism,

00:02:54.140 | and those hormones are called T4 and T3.

00:02:56.760 | So if this is already sounding like a lot of information,

00:02:59.100 | it's really easy, I promise.

00:03:01.380 | Releasing hormone comes to the brain,

00:03:03.860 | stimulating hormone comes from the pituitary,

00:03:05.900 | and in this case, we're talking about the thyroid

00:03:08.580 | binding up that stimulating hormone and saying,

00:03:11.020 | "Oh, I need to release something,"

00:03:12.300 | and it releases T4 and T3.

00:03:13.740 | And guess what?

00:03:14.580 | You can basically forget about T4.

00:03:16.300 | T4, it's not completely inactive, it has some roles,

00:03:19.460 | but T3 is the one that's more or less active.

00:03:22.200 | Now, what does thyroid hormone do?

00:03:25.140 | The main role of thyroid hormone of T3

00:03:29.740 | is to promote metabolism,

00:03:32.100 | and that doesn't just mean the consumption of energy,

00:03:35.140 | it means the utilization of energy,

00:03:37.100 | including the buildup of tissues.

00:03:39.500 | So it acts on all sorts of target tissues in the body.

00:03:42.900 | It acts on muscle, it acts on the liver,

00:03:46.580 | it acts on the cartilage, it acts on the bone.

00:03:50.340 | It's involved in taking fats

00:03:52.340 | and breaking them down into fatty acids

00:03:54.580 | and converting those into ATP,

00:03:57.040 | which is an important thing for cells to use energy.

00:04:01.360 | It's also involved in taking sugars

00:04:03.780 | and turning those into energy.

00:04:05.720 | And yes, it goes to adipose tissue, to fat.

00:04:09.160 | We have different kinds of fat that we'll talk about today,

00:04:11.060 | but it goes to white fat and it liberates

00:04:13.740 | or helps liberate some of the fats from those fat cells

00:04:17.660 | and use them for energy.

00:04:19.220 | And this is why higher thyroid

00:04:20.580 | is associated with leaner bodies.

00:04:22.940 | Lower thyroid is associated with less lean bodies.

00:04:26.860 | One thing that's absolutely key and is actionable,

00:04:29.220 | we're right there already in discussing tools, is iodine.

00:04:33.180 | Iodine is most common in sea salt, in kelp, and in seaweed.

00:04:41.180 | And most people can get enough iodine

00:04:44.120 | from the food they eat and/or the table salt they consume.

00:04:47.880 | Almost all table salt from all over the world,

00:04:51.760 | regardless of where you are, contains iodine.

00:04:54.540 | The thyroid needs iodine

00:04:56.900 | in order to produce thyroid hormone.

00:04:59.140 | Iodine combines with an amino acid

00:05:01.740 | that we've talked about before called L-tyrosine.

00:05:04.820 | L-tyrosine comes from meat, from nuts.

00:05:07.100 | There are some plant-based sources as well.

00:05:09.300 | It is the precursor to dopamine.

00:05:12.160 | But in the thyroid, iodine combines or works with L-tyrosine

00:05:17.160 | to produce T3 and T4, the thyroid hormone.

00:05:20.660 | So you absolutely need sufficient iodine.

00:05:23.860 | You need sufficient L-tyrosine.

00:05:26.300 | And then you also need something else,

00:05:27.620 | which is called selenium.

00:05:28.860 | Selenium is important in order for thyroid hormone

00:05:32.280 | to be made because of the way that it allows L-tyrosine

00:05:37.180 | and iodine to interact.

00:05:39.860 | And the thing is, most people aren't getting enough selenium

00:05:44.500 | because they don't eat foods that are high in selenium.

00:05:46.420 | Now, how much selenium you need

00:05:47.980 | will depend on where you live.

00:05:49.260 | It actually varies country by country.

00:05:51.300 | Some countries, I found,

00:05:52.780 | say that you should get 100 micrograms.

00:05:56.500 | Some say 200, some say 155.

00:05:58.940 | The average was about 155 micrograms,

00:06:01.100 | the countries I looked at.

00:06:02.720 | People who are trying to increase thyroid levels

00:06:05.100 | might want to consume more selenium.

00:06:07.340 | And if you consume a vitamin, of course,

00:06:08.860 | you want to make sure if it has selenium

00:06:11.700 | that you're not overdoing it

00:06:12.620 | by consuming a lot of selenium-rich foods either.

00:06:15.540 | Brazil nuts are the heavyweight champion of foods

00:06:18.080 | to get selenium from.

00:06:19.780 | It has very high concentrations of selenium.

00:06:21.980 | In just six or eight,

00:06:24.020 | Brazil nuts contain something like 550 micrograms

00:06:28.740 | of selenium.

00:06:29.720 | It's also present in fish.

00:06:31.460 | Ham, of all things, contains a lot of selenium.

00:06:35.700 | For whatever reason, pork does.

00:06:37.380 | I'm not a big consumer of pork.

00:06:39.140 | Beef has some selenium.

00:06:40.740 | But what's interesting, if you look at the sources,

00:06:42.820 | you know, pork, beef, turkey, chicken,

00:06:45.260 | cottage cheese, eggs, brown rice,

00:06:48.500 | what you want to understand

00:06:50.900 | is that they have something

00:06:52.220 | like 30 to 50 micrograms of selenium.

00:06:55.060 | So if you're not eating Brazil nuts,

00:06:56.340 | and I'm guessing most people aren't,

00:06:58.940 | and you're not eating a lot of animal-based foods,

00:07:01.660 | which I know many of you aren't,

00:07:03.240 | then you're probably not getting enough selenium.

00:07:06.400 | And again, you can have these levels measured,

00:07:08.840 | or you can just check what you're consuming

00:07:10.900 | and figure out whether or not you're meeting the ration

00:07:13.880 | that you need in order to get healthy levels of thyroid.

00:07:17.520 | I also want to mention that for children,

00:07:20.660 | their daily requirements of selenium are much lower,

00:07:23.740 | as low as, you know, 30 or 40 micrograms

00:07:26.080 | for kids 14 years or younger.

00:07:28.940 | And again, that's micrograms, not milligrams.

00:07:31.560 | So again, look into what you need,

00:07:32.880 | but if you're somebody who's interested

00:07:34.980 | in keeping thyroid function healthy and productive,

00:07:39.980 | then you certainly want to make sure

00:07:42.060 | you're getting enough iodine,

00:07:43.180 | you're getting enough selenium,

00:07:45.060 | and you're getting enough L-tyrosine.

00:07:46.860 | And it's interesting when you start looking

00:07:48.340 | at the various foods, especially highly processed foods,

00:07:51.220 | then you start to realize that perhaps many people,

00:07:54.100 | maybe you, are not.

00:07:55.700 | If you're curious how thyroid actually increases metabolism,

00:07:59.040 | allows you to eat more, et cetera,

00:08:00.420 | it relates to something we covered last issue,

00:08:02.660 | which is glucose.

00:08:04.140 | Remember, when you eat something, blood sugar goes up,

00:08:06.340 | insulin is secreted from the pancreas,

00:08:08.820 | and it makes sure that blood glucose doesn't go too high,

00:08:10.940 | which can damage tissues, or too low,

00:08:12.940 | which can make you hypoglycemic.

00:08:14.600 | Thyroid increases glucose uptake by various tissues,

00:08:19.580 | in particular, muscle and bone.

00:08:21.820 | It actually can increase bone mineral density,

00:08:24.180 | which is a really good thing as you get older.

00:08:26.180 | When I say older, I mean basically 30 and older.

00:08:29.140 | The reason you can recover more quickly from injuries

00:08:31.880 | if you have a healthy thyroid and healthy thyroid pathways

00:08:35.360 | is because you can consume energy,

00:08:37.780 | that energy is diverted toward bone repair

00:08:40.860 | and muscle repair and cartilage repair.

00:08:43.100 | And so the way it does this, again, is by increasing ATP,

00:08:46.840 | but the whole idea here is that iodine, selenium,

00:08:51.420 | L-tyrosine allow thyroid to be at healthy levels

00:08:53.900 | so that thyroid then can take glucose in the blood

00:08:57.220 | and divert it to tissues for it to be used,

00:08:59.780 | in particular, your brain.

00:09:01.060 | And that's why the ability of your brain to use glucose

00:09:03.840 | or ketones, for that matter,

00:09:05.180 | is going to be aided by having healthy thyroid.

00:09:08.540 | So do the things, take the things, eat the things

00:09:11.500 | that are going to allow you to have healthy levels

00:09:14.000 | of thyroid hormone.

00:09:15.460 | If you're concerned about having excessively high

00:09:18.200 | or excessively low levels of thyroid hormone,

00:09:20.660 | absolutely look up what the symptoms are,

00:09:23.020 | talk to your physician.

00:09:24.940 | And there are a number of good treatments.

00:09:26.640 | I didn't talk about prescription drugs

00:09:28.420 | that can improve symptoms related to hypo or hyperthyroid.

00:09:32.780 | Of course, they have synthesized thyroid.

00:09:36.260 | So if you don't make enough thyroid, you can take thyroid.

00:09:38.780 | It's by prescription.

00:09:40.220 | If you have too much thyroid,

00:09:42.260 | sometimes they'll take out the thyroid gland

00:09:44.700 | or they can administer drugs that will either block

00:09:47.880 | receptors or will interfere with some of the pathways

00:09:51.180 | from the brain to the pituitary

00:09:53.180 | or from the pituitary to the thyroid

00:09:55.040 | in order to adjust thyroid hormone that way.

00:09:57.780 | So there are the big guns in terms of the treatments

00:10:02.180 | for different thyroid disorders,

00:10:04.180 | but we're not talking about thyroid disorders.

00:10:06.080 | We're talking about how to get and maintain thyroid levels

00:10:09.400 | in healthy ranges and some straightforward ways to do that

00:10:12.380 | through diet and supplementation.

00:10:14.400 | Next, we're going to talk about growth hormone.

00:10:17.180 | Growth hormone is a pretty straightforward one

00:10:20.000 | for you to understand now,

00:10:21.000 | because it follows the exact same logic as thyroid hormone.

00:10:24.800 | In fact, their functions are so closely overlapping

00:10:28.400 | that you're probably going to think,

00:10:29.600 | why do you have these two systems?

00:10:31.240 | So just very briefly, growth hormone releasing hormone.

00:10:36.240 | So remember, releasing means it comes from the brain,

00:10:38.420 | comes from the brain and tells the pituitary

00:10:40.680 | to release growth hormone.

00:10:42.200 | And then growth hormone is released into the bloodstream

00:10:44.320 | where it goes and acts on a ton of tissues,

00:10:46.600 | muscle, ligaments, bone, fat, et cetera.

00:10:50.960 | To increase metabolism.

00:10:52.520 | It sounds just like thyroid hormone

00:10:56.020 | and they do work in parallel.

00:10:57.360 | And that's why we've lumped them together

00:10:58.620 | in the same episode.

00:10:59.460 | They increase metabolism and repair and growth of tissues.

00:11:03.440 | Today, we're going to talk about the things

00:11:05.060 | that anyone can do to increase growth hormone.

00:11:07.760 | And there are reasons why certain people

00:11:09.520 | would want to do that.

00:11:10.360 | People that make normal, quote unquote,

00:11:13.600 | levels of growth hormone might want to do that as they age,

00:11:17.320 | because during puberty and development,

00:11:19.840 | the pituitary is churning out tons of growth hormone.

00:11:22.720 | It's responsible for the growth, not surprising,

00:11:25.700 | of the body and all its features,

00:11:28.480 | height just being one of those.

00:11:31.120 | And so as we age, we make less growth hormone.

00:11:33.940 | And that is one of the reasons why we recover more slowly

00:11:38.000 | from injuries.

00:11:39.120 | It's one of the reasons why we accumulate body fat.

00:11:42.480 | And it's one of the reasons why our metabolism slows.

00:11:45.140 | And so growth hormone replacement therapy

00:11:47.660 | has been tremendously popular in the last 20 years,

00:11:51.560 | which is not to say it doesn't carry its problems.

00:11:53.660 | It does.

00:11:54.540 | Here's one of the major problems

00:11:56.140 | with injecting growth hormone.

00:11:58.380 | Not saying people shouldn't do this

00:11:59.820 | if the doctor has approved it,

00:12:01.240 | or it's in keeping with their particular life goals,

00:12:04.900 | but growth hormone, if it's in levels that are too high,

00:12:09.320 | will cause growth of all tissues.

00:12:12.440 | So not just muscle, not just reduction in body fat

00:12:16.020 | by metabolizing, by allowing fatty acids

00:12:20.480 | to be pulled out of storage and used for ATP,

00:12:23.060 | but it will also cause increase in growth of the heart

00:12:27.140 | and the lungs and the liver and the spleen.

00:12:29.540 | And so this is the concern with abuse of growth hormone.

00:12:32.980 | So we're not going to be talking

00:12:33.820 | about abuse of growth hormone.

00:12:35.020 | We will, however, talk about tools that anyone can use

00:12:38.600 | to increase levels of growth hormone.

00:12:40.780 | Some of them are behavioral,

00:12:41.820 | some of them are supplement-based,

00:12:43.520 | and some of them interact with behaviors and supplements.

00:12:47.180 | And what's cool about the discussion about growth hormone

00:12:50.260 | is that the tools that exist out there

00:12:52.660 | to increase growth hormone are very actionable.

00:12:55.820 | There are things that can increase growth hormone

00:12:57.900 | three, four, 500% or more.

00:13:02.020 | And even though that's a short-lived increase,

00:13:05.140 | they can have very powerful effects on metabolism

00:13:07.400 | and on repair of tissues.

00:13:08.780 | So let's talk about those.

00:13:10.020 | As always, I want to emphasize,

00:13:11.660 | talk to a doctor before you do anything,

00:13:14.380 | including remove any treatments.

00:13:16.900 | Growth hormone is released every night when you go to sleep,

00:13:20.240 | and it's released in the early part of sleep

00:13:22.820 | during so-called slow-wave sleep.

00:13:24.720 | So the two conditions that have to be met

00:13:28.460 | in order for growth hormone to be secreted regularly

00:13:31.860 | for tissue repair, et cetera,

00:13:34.300 | are you need to get into slow-wave sleep,

00:13:37.260 | the so-called deep sleep,

00:13:39.180 | and you need blood insulin and glucose to be relatively low.

00:13:44.180 | So eating within two hours of going to sleep

00:13:46.900 | is going to suppress growth hormone release.

00:13:48.780 | That's very clear.

00:13:50.420 | So what is special about this early phase of sleep?

00:13:54.580 | What in particular about slow-wave deep sleep

00:13:58.420 | allows the pituitary to release growth hormone?

00:14:01.340 | So the answer is it's a delta wave activity in the brain.

00:14:05.700 | Delta waves are these big, giant waves of activity

00:14:09.420 | in the brain that correlate with slow-wave sleep

00:14:13.020 | as opposed to faster waves of activity

00:14:14.620 | that associate with rapid eye movement sleep.

00:14:17.140 | It's the delta waves of activity,

00:14:18.740 | these sweeping big waves of activity in the neurons

00:14:20.940 | that stimulate the brain to stimulate the pituitary,

00:14:23.660 | 'cause once you understand that,

00:14:25.340 | then you have something to anchor to in terms of thinking,

00:14:27.860 | what are the things I can do in waking

00:14:30.580 | that will allow me to release more growth hormone,

00:14:32.980 | which for most people is going to be a good thing.

00:14:35.380 | Now, the delta wave activity

00:14:37.100 | and the slow-wave activity in the brain

00:14:39.700 | being very important for growth hormone release

00:14:42.780 | and growth hormone release being so important

00:14:44.860 | for metabolic functions and peeling away unwanted body fat

00:14:48.800 | and repairing tissues, et cetera, forces us to ask,

00:14:52.300 | well, what other things can we do in waking

00:14:54.820 | in order to increase growth hormone release?

00:14:57.380 | So let's start with the ones that have

00:14:59.380 | a potentially big effect,

00:15:01.940 | but are a little bit harder to access.

00:15:03.800 | And for that, I want to point toward a book,

00:15:06.620 | which is really kind of interesting.

00:15:08.140 | It's not focused on growth hormone,

00:15:09.900 | but the book is called "Altered Traits."

00:15:12.380 | This is the book.

00:15:13.880 | It's an excellent book.

00:15:15.700 | "Altered Traits" by Goldman and Davidson.

00:15:18.540 | "Science Reveals How Meditation Changes Your Mind,

00:15:21.420 | Brain, and Body."

00:15:22.820 | Very interesting book.

00:15:24.540 | For those of you that are interested in meditation,

00:15:26.980 | and perhaps those of you who are not,

00:15:29.580 | but are considering it,

00:15:30.740 | what they talk about in this book is the fact

00:15:33.660 | that meditation has two separate lines of effects.

00:15:36.580 | One of those lines of effects

00:15:38.820 | are things that change your state.

00:15:40.660 | So you're stressed, you sit down, you meditate,

00:15:43.320 | and you relax, and you go into a particular state.

00:15:45.300 | The other are the changes that occur over time,

00:15:48.060 | and those are changes in trait.

00:15:50.060 | So personality can actually change

00:15:52.120 | with long bouts of TM meditation or repeated meditation.

00:15:57.120 | In any case, the reason we're talking

00:15:59.500 | about altered traits today

00:16:01.700 | is because certain types of meditation

00:16:06.300 | can get people's brains into states

00:16:09.080 | that very closely mimic slow-wave sleep.

00:16:12.260 | So what this means is for people

00:16:14.900 | that are interested in increasing growth hormone,

00:16:17.900 | a meditation practice that allows you to get

00:16:20.420 | into these slow-wave delta-type frequency activity

00:16:25.420 | in the brain may be very beneficial

00:16:29.100 | because, as I mentioned before,

00:16:30.220 | that's what's gating growth hormone release.

00:16:32.380 | It's not just a circadian phenomenon.

00:16:34.220 | It's actually controlled by these brain waves.

00:16:37.200 | Now let's move to the things that one can do

00:16:39.860 | that have been shown to have, let's just be honest,

00:16:43.380 | pretty enormous effects on growth hormone release in waking,

00:16:47.340 | and these are things that are very actionable.

00:16:49.860 | One of the things that can have a dramatic effect

00:16:52.220 | on levels of growth hormone release in waking,

00:16:55.020 | as well as in sleep the following night, is exercise.

00:16:59.860 | There are hundreds, if not thousands,

00:17:01.700 | of studies measuring growth hormone,

00:17:04.140 | both during or sometimes after exercise

00:17:08.420 | or the following night.

00:17:10.740 | And the conclusion that one takes away from all of these

00:17:14.180 | is that exercise has to be of particular duration

00:17:18.780 | and intensity in order to get growth hormone release.

00:17:21.780 | So first, I'm just going to tell you what I found

00:17:24.180 | to be the maximum amount of growth hormone release

00:17:26.880 | as it relates to a particular form of exercise.

00:17:29.880 | The particular form of exercise is either weight training

00:17:33.200 | or it can be endurance training,

00:17:36.800 | but the endurance training and the weight training

00:17:39.120 | actually have to be limited to about 60 minutes,

00:17:42.400 | not much longer.

00:17:43.420 | A proper warmup seems to accelerate

00:17:46.520 | the release of growth hormone

00:17:48.380 | once the hard work phase starts.

00:17:50.760 | So 10 minutes of warmup or so was the number

00:17:54.080 | that I extracted from all these studies.

00:17:55.860 | And when you say warmup,

00:17:56.840 | it doesn't mean just warm up the limbs and tissues

00:17:59.540 | that you're going to use so you don't get injured,

00:18:01.080 | actually warm the body.

00:18:02.920 | Getting the body warm as a warmup seems to be important

00:18:05.780 | because temperature of the body

00:18:07.760 | seems to be an important condition

00:18:10.000 | or prerequisite for certain patterns of exercise

00:18:13.000 | to maximize growth hormone release.

00:18:14.840 | So if it's weight-bearing exercise,

00:18:16.760 | it would be getting close to that final repetitions

00:18:19.800 | where you can't complete them,

00:18:20.820 | but not pushing through those or even going to failure,

00:18:23.320 | but getting close leads to anywhere from 300 to 500%

00:18:28.060 | increases in resting growth hormone levels

00:18:30.620 | and 300 to 500% increases in growth hormone

00:18:34.720 | the following night when you go to sleep,

00:18:36.980 | which is incredible.

00:18:38.960 | One of the other conditions that seemed to be important

00:18:41.380 | again was to have relatively low blood glucose.

00:18:44.420 | So probably not eating too close to exercise

00:18:46.980 | or not ingesting a lot of sugars during the exercise.

00:18:51.500 | That was supported by the fact that ingestion

00:18:53.500 | of a sports drink that contains caloric sugar

00:18:56.560 | immediately flatlined the growth hormone levels.

00:18:59.440 | So really interesting relationship

00:19:01.400 | between insulin, glucose, and growth hormone.

00:19:04.480 | And then the other interesting thing

00:19:07.120 | was that even after the exercise,

00:19:09.800 | taking body temperature back down to normal levels

00:19:12.720 | relatively quickly seemed to be associated

00:19:16.360 | with these big spikes in growth hormone.

00:19:18.360 | Otherwise what would happen is you get these big spikes

00:19:20.280 | in growth hormone, but if the exercise went too long

00:19:23.200 | or if body temperature remained too high for too long,

00:19:26.000 | then you didn't get the second increase

00:19:27.960 | in growth hormone the following night.

00:19:29.840 | Let's talk about supplements.

00:19:31.040 | So this has been known about for some time,

00:19:33.640 | but arginine, the amino acid arginine

00:19:37.240 | can increase growth hormone levels substantially.

00:19:40.980 | The levels and the amounts of arginine required

00:19:44.520 | to get big growth hormone release increases

00:19:47.480 | is pretty substantial.

00:19:48.600 | So some people will take arginine before bedtime.

00:19:51.780 | Some people will take it before exercise.

00:19:54.640 | The prerequisite again is low blood glucose.

00:19:58.320 | Blood glucose is high, it's going to quash the effect.

00:20:01.720 | The amounts of arginine that people take

00:20:04.620 | are anywhere from three grams to 10 grams

00:20:09.160 | or sometimes even more.

00:20:10.560 | Although this is definitely a case of more is not better.

00:20:14.480 | There is a threshold at which growth hormone release

00:20:17.720 | is actually blunted by taking

00:20:19.760 | more than nine grams of arginine.

00:20:22.760 | Now nine grams of arginine orally is a lot of pills.

00:20:25.600 | It's at minimum nine pills

00:20:27.920 | and it can cause some GI disturbance, right?

00:20:31.540 | People can feel nauseous.

00:20:32.680 | Some people will throw it up.

00:20:34.040 | What's interesting, however,

00:20:35.480 | is that whether or not it's by mouth or by vein,

00:20:39.840 | taking arginine can dramatically increase

00:20:43.080 | growth hormone release 400 to 600% above baselines.

00:20:46.640 | These are huge increases in growth hormone.

00:20:50.040 | Now here is something really important

00:20:52.120 | and interesting to note,

00:20:53.560 | which is that increasing arginine levels

00:20:57.700 | with the specific goal of increasing growth hormone release

00:21:01.240 | can actually short circuit the effects of exercise

00:21:06.240 | on growth hormone.

00:21:07.140 | Several studies I looked at,

00:21:08.720 | looked at the interaction of taking arginine

00:21:12.560 | and the exercise or just the arginine

00:21:16.160 | or just the exercise alone.

00:21:17.560 | And so you don't, unfortunately,

00:21:19.840 | if growth hormone increases your goal,

00:21:21.460 | you don't unfortunately get to increase growth hormone

00:21:24.000 | 800% by taking arginine and exercising.

00:21:26.640 | It always seems to be clamped at about 300 to 500% increases.

00:21:30.440 | So hopefully that's clear.

00:21:31.840 | One thing that's particularly interesting to me

00:21:33.520 | as somebody who's in his forties

00:21:35.280 | is that it's actually between ages 30 and 40

00:21:39.920 | that the amount of growth hormone that you release

00:21:42.400 | each night is reduced by two to threefold.

00:21:46.160 | And since everybody goes through

00:21:47.440 | this age-related decline very dramatically,

00:21:50.480 | it seems to me that the things

00:21:51.960 | that we're supposed to be doing anyway,

00:21:53.440 | like exercising, like trying not to eat

00:21:55.760 | too close to bedtime, trying to optimize sleep,

00:21:57.680 | all of these are wonderful tools

00:21:59.080 | that we should be pursuing and perhaps using.

00:22:03.520 | And they can actually offset

00:22:06.200 | the two to threefold decrease, right?

00:22:08.320 | If we're talking about a two to threefold decrease

00:22:10.080 | for people that are in their thirties and forties

00:22:12.200 | and then we're talking about increases from exercise

00:22:15.240 | or from maybe from supplementation,

00:22:17.160 | but certainly from exercise of 300 to 500%,

00:22:20.960 | well then all of a sudden we're in a position

00:22:22.960 | to actually offset the age-related decline

00:22:25.160 | in growth hormone completely just through behaviors.

00:22:27.760 | And I think that's quite interesting and quite powerful.

00:22:30.960 | Now I'd like to discuss a way

00:22:32.200 | that anyone can increase their levels

00:22:33.960 | of growth hormone dramatically.

00:22:35.960 | And when I say dramatically, I mean dramatically.

00:22:38.320 | I'll get to the numbers in a couple minutes,

00:22:40.200 | but we have to remember how growth hormone

00:22:44.220 | is released in the first place.

00:22:46.280 | Remember, it all starts in the brain, in the hypothalamus.

00:22:49.800 | The hypothalamus is a brain area that controls

00:22:52.360 | things like sexual behavior, temperature regulation,

00:22:56.200 | circadian behavior, meaning when you want to be awake

00:22:58.600 | and when you want to be asleep, aggression, all of that.

00:23:02.280 | There are other brain areas involved too,

00:23:03.960 | but it has a rich collection of different neurons

00:23:07.000 | involved in all these very basic functions.

00:23:10.680 | Now, as we talked about the releasing hormones,

00:23:14.380 | the growth hormone releasing hormone

00:23:16.720 | comes from neurons in the hypothalamus.

00:23:19.120 | Those then communicate with the pituitary

00:23:21.520 | and the pituitary releases growth hormone

00:23:24.720 | and then the growth hormone acts

00:23:26.000 | on all these different tissues,

00:23:27.120 | muscle, liver, cartilage, et cetera, body fat.

00:23:30.200 | Makes them use energy.

00:23:33.040 | That's why you lose body fat

00:23:34.080 | when growth hormone levels are high.

00:23:35.680 | It makes you grow muscle, strengthens bones, et cetera.

00:23:39.280 | Now, one of the things that has a profound effect

00:23:45.480 | on growth hormone levels,

00:23:47.640 | growth hormone release is temperature.

00:23:50.600 | Now, the data on this are very strong

00:23:52.840 | and the data come from both animal studies

00:23:55.040 | and human studies.

00:23:56.680 | And if you're guessing which direction this is going to go,

00:24:00.240 | you can probably imagine that making animals

00:24:03.160 | or people warmer is the way to go

00:24:06.120 | if you want to increase growth hormone.

00:24:08.220 | Now, anytime you're going to increase temperature

00:24:10.960 | of yourself or anyone else or an animal, it is risky.

00:24:14.680 | I want to be really clear about this.

00:24:16.200 | Not everyone should engage in the behaviors

00:24:19.160 | I'm about to describe.

00:24:21.080 | But, and I should just say the reason it's risky

00:24:24.120 | is it doesn't take much of a temperature increase

00:24:26.040 | in the brain to cook the brain, to cook neurons.

00:24:28.800 | And after that point, neurons can't come back

00:24:31.640 | and people can die from hyperthermia.

00:24:34.360 | However, there are really strong data

00:24:37.640 | pointing to the fact that sauna,

00:24:39.840 | aka deliberate hyperthermia, not too high, however,

00:24:45.840 | that sauna can increase the release of growth hormone

00:24:49.260 | and other hormones.

00:24:50.960 | And what's so dramatic about this literature

00:24:53.000 | is the size of the effects that are reported.

00:24:56.400 | Entering environments where it's very hot

00:24:59.560 | for short periods of time,

00:25:00.760 | anywhere from 20 minutes to 30 minutes,

00:25:03.580 | where the temperature is 80 degrees Celsius

00:25:08.380 | to a hundred degrees Celsius,

00:25:09.800 | has been shown to increase growth hormone release 16 fold.

00:25:14.800 | That's right, 16 fold, that's 1,600%.

00:25:18.960 | Now, there are also effects on other hormones,

00:25:21.240 | prolactin, cortisol, et cetera.

00:25:23.700 | So the pattern that was described in this study,

00:25:27.160 | and there've been many studies now,

00:25:30.040 | endocrine effects of repeated sauna

00:25:32.040 | were done in 17 humans.

00:25:36.380 | They actually had to do this three days in a row.

00:25:38.440 | And the pattern was to get into the sauna for 20 minutes,

00:25:41.680 | followed by 30 minutes of cooling,

00:25:43.280 | followed by 20 minutes sauna again,

00:25:45.760 | led to a five-fold increase in growth hormone.

00:25:47.820 | And then by doing that day after day after day,

00:25:52.280 | on the third day,

00:25:53.320 | you would see these huge increases of like 16 fold,

00:25:56.600 | up to 16 fold.

00:25:57.760 | But these increases in growth hormone are tremendous.

00:26:00.080 | And what they probably stem from

00:26:02.280 | are increased activity of neurons within the hypothalamus

00:26:05.920 | that stimulate growth hormone release from the pituitary.

00:26:08.840 | And that's probably because the growth hormone

00:26:11.920 | releasing hormone neurons in the hypothalamus

00:26:14.740 | sit very closely and may even be intermixed

00:26:18.120 | with some of the neurons in the hypothalamus

00:26:20.320 | that regulate heat and body temperature.

00:26:22.800 | Remember, metabolism is in part a heat.

00:26:25.520 | It's like a furnace of how much energy you're consuming

00:26:28.160 | and using for building or for energy usage purposes.

00:26:33.100 | So sauna can be very, very interesting.

00:26:35.640 | And again, it's 20 minutes, 30 minute cooling,

00:26:38.140 | 20 minutes again, proceed with extreme caution.

00:26:42.300 | But nonetheless, these are pretty extreme effects

00:26:45.240 | in terms of their abilities

00:26:47.100 | to increase growth hormone levels.

00:26:49.160 | There's a kind of new area that's developing now

00:26:52.220 | that I think deserves our attention,

00:26:54.320 | not because I'm encouraging it,

00:26:55.600 | but because it is happening.

00:26:57.040 | And those are peptides.

00:26:58.560 | So these days you hear a lot about peptides.

00:27:01.120 | I'd like to clarify a little bit about what peptides are.

00:27:04.160 | Peptides is a really huge category of biological compounds.

00:27:08.980 | Peptides are just strings of amino acids, right?

00:27:12.080 | So we've talked about l-tyrosine, arginine, ornithine.

00:27:14.560 | Those are amino acids.

00:27:15.400 | Those are individual amino acids.

00:27:16.920 | And those are put together into little small peptides

00:27:21.120 | or they're what are called polypeptides,

00:27:23.380 | which are just longer peptides.

00:27:25.180 | Turns out that for any substance like growth hormone

00:27:29.480 | or growth hormone releasing hormone,

00:27:31.080 | it's made up of different amino acids

00:27:32.680 | in different sequences.

00:27:33.700 | Just like your genes are made up of A's and G's

00:27:36.800 | and C's and T's, nucleotides in different sequences.

00:27:39.200 | It's like a recipe.

00:27:40.460 | Peptides tend to be short sequences of amino acids

00:27:46.240 | that resemble a hormone enough

00:27:48.920 | or resemble some other peptide enough

00:27:51.600 | that it can lead to the similar or same effects

00:27:54.120 | when you inject them.

00:27:55.260 | So for example, we make growth hormone releasing hormone

00:27:59.480 | from our brain,

00:28:00.320 | which stimulates growth hormone from the pituitary.

00:28:02.200 | But people now will take things like sermorelin,

00:28:06.680 | S-E-R-M-O-R-E-L-I-N, sermorelin,

00:28:11.680 | which is not the entire peptide sequence

00:28:14.600 | of growth hormone releasing hormone,

00:28:16.520 | but it's a subset of those.

00:28:18.320 | Then that stimulates the release of growth hormone

00:28:20.880 | from the pituitary.

00:28:22.000 | So this is not taking growth hormone,

00:28:24.240 | this is taking the stimulating hormone

00:28:26.760 | or what's often called a secretagogue or a mimic, all right?

00:28:30.880 | It causes a secretion of the hormone that one wants.

00:28:35.160 | Sermorelin is prescription.

00:28:36.760 | Do they work? Yes.

00:28:39.160 | Do they shut down your natural production

00:28:41.680 | of growth hormone releasing hormone?

00:28:44.400 | Well, the answer is yes,

00:28:47.000 | but some of these peptides actually have the effect

00:28:50.060 | of changing gene expression.

00:28:52.120 | Because as you recall,

00:28:53.060 | growth hormone in big increases in growth hormone

00:28:56.420 | that are short-lived like sauna,

00:28:58.680 | or I should say exercise or arginine or sauna,

00:29:02.200 | it seems like has these huge effects.

00:29:04.160 | Those are transient,

00:29:05.960 | but when one is injecting over and over a constant level,

00:29:09.520 | you can put into action gene expression programs

00:29:12.540 | that can be long-lived.

00:29:13.640 | And let's say you have a particular tumor in the body.

00:29:16.640 | Tumors will grow when they see growth hormone,

00:29:18.800 | even if that tumor is unhealthy for you, right?

00:29:21.580 | You've got growth of tissues all over the body.

00:29:23.380 | So again, not promoting their use,

00:29:25.020 | but they're definitely out there.

00:29:25.980 | And so now if you hear about them

00:29:27.900 | or if someone's talking to you about them,

00:29:29.380 | now hopefully you have a better understanding

00:29:30.940 | about their underlying biology,

00:29:32.340 | and you can think rationally about whether or not

00:29:34.500 | they are the right decision for you.

00:29:37.260 | Okay, once again, covered an enormous amount of material.

00:29:41.540 | Hopefully now you understand thyroid hormone

00:29:43.820 | and what it does and a little bit about its mechanism,

00:29:46.220 | or maybe a lot,

00:29:47.060 | and growth hormone and what it does

00:29:48.760 | and how both of them take care of our metabolism.

00:29:52.400 | They dictate how many nutrients we can eat and make use of.

00:29:55.900 | They can pull from body fat stores,

00:29:58.080 | repair muscle, repair cartilage.

00:29:59.940 | They really are incredible compounds,

00:30:01.960 | and they're actionable.

00:30:03.480 | There are things that we can do,

00:30:04.420 | like getting that early phase of sleep,

00:30:06.920 | perhaps supplementing with arginine, maybe not.

00:30:10.080 | Hopefully getting adequate exercise,

00:30:12.520 | warming up properly,

00:30:13.600 | not making the exercise too long or too intense will help,

00:30:16.520 | maybe sauna or things like it,

00:30:18.760 | you know, deliberate safe hyperthermia,

00:30:21.720 | with the emphasis on safe,

00:30:23.000 | might be things that are of use.

00:30:24.480 | And so now hopefully you understand

00:30:26.320 | not just thyroid and growth hormone,

00:30:27.820 | but the logic that underlies thyroid hormone,

00:30:30.520 | growth hormone, estrogen, testosterone,

00:30:33.140 | why we eat, why we stop eating,

00:30:35.240 | cholecystokinin, ghrelin.

00:30:37.340 | If these names don't mean anything to you,

00:30:39.200 | then perhaps go back and listen to those episodes.

00:30:41.280 | But regardless, I hope that you come away from this

00:30:43.940 | with a deeper understanding about these hormones,

00:30:46.680 | which are so powerful in controlling

00:30:48.980 | the way our brain functions,

00:30:50.420 | and the interplay between the brain and hormones,

00:30:52.820 | because it is really a bi-directional conversation.

00:30:56.260 | The brain is telling the body what hormones to make,

00:30:58.380 | the hormones are influencing all the tissues of the body,

00:31:00.620 | but also telling the brain whether or not to eat more

00:31:02.940 | or grow more or think more, et cetera.

00:31:06.100 | So I really appreciate your time and attention.

00:31:08.940 | If you like this podcast and you're finding it useful,

00:31:12.860 | please recommend it to other people.

00:31:15.000 | And last but not least,

00:31:16.860 | I thank you for your time and attention,

00:31:18.620 | and above all, for your interest in science.

00:31:20.940 | (upbeat music)

00:31:23.520 | (upbeat music)

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

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