Essentials: Control Your Brain Chemistry for Focus, Motivation & Well-Being

**Andrew Huberman** (0:00)
Welcome to Huberman Lab 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 ophthalmology at Stanford School of Medicine. Today, we're going to discuss your brain chemistry and how to control and optimize your brain chemistry for all aspects of mental health, physical health and performance. The important thing to know is that your brain and your spinal cord and the rest of your so-called nervous system control all the organs of your body and that all the organs of your body feed back, meaning they communicate through chemicals and other means to your nervous system. And vitally important is the fact that which neural circuits are active and which neural circuits are likely to be less active at any given moment depends on two major categories of chemicals. It depends on hormones and it depends on so-called neuromodulators. And the four neuromodulators that we're going to talk about today that are of the utmost importance for your goals are dopamine, epinephrine, also called adrenaline, serotonin, and acetylcholine. There are many features of how neuromodulators work, but for sake of today's discussion, we only need to focus on two of those features. And those are fast-acting features and longer, slower features or what we call baseline features. Now, perhaps surprisingly, I'd like to focus on the slow actions of the neuromodulators first because those slow actions of the neuromodulators are happening in you and in me and in everyone right now. And they set the backdrop, the context in which the various tools to manipulate dopamine, epinephrine, serotonin, or acetylcholine will work.
What do I mean by the context or the backdrop or the baseline? Well, it's fair to say that most people are awake during the daytime and asleep at night. So schedules of sleep and wakefulness will vary, but in general, everybody, regardless of whether or not you're nocturnal or you're so-called diurnal, you're awake during the day, pretty much everybody follows a schedule in which from zero to nine hours after waking, that is from the time you wake up until about nine hours later, the neuromodulators dopamine and epinephrine tend to be at their highest levels that they will be at any point in the 24-hour period, in any period of the day.
So we can call this zero to nine hour period, phase one of the day, just for simplicity. And I've referred to this before in a previous episode, but not in this exact context. From nine to about 16 hours is what we will call phase two. And that's when dopamine and epinephrine levels tend to subside a bit compared to the earlier phase one part of the day and serotonin levels start to increase.
And then phase three of the 24-hour cycle, which is from about, and again, about the zero approximates, from about 17 hours after waking until about 24 hours after waking is phase three of the day. We're not going to focus too much on phase three today because phase three of the 24-hour cycle, that 17 to 24-hour period is one in which you ought to be deeply asleep, whether or not you're nocturnal or diurnal. So we're mainly going to focus on what we're calling phase one and phase two. Phase one being this dopamine epinephrine dominated phase of our day and phase two being this more serotonergic or serotonin dominated portion of the day. And then you might say, well, what about acetylcholine?
You forgot about acetylcholine. Well, we didn't forget about acetylcholine. Acetylcholine is under control more in terms of what we happen to be doing at any given moment, whether or not we're focusing or not focusing, whether or not we're learning or not learning. And here I'm referring to acetylcholine specifically in the context of the brain and thinking, because as some of you are probably shouting out there, right? If you're exercise physiologists or you know anything about how the brain controls movement, acetylcholine is used at the nerve to muscle synapse, right? So neurons don't just control other neurons electrically. The way you are able to move, in fact, is because neurons are controlling the electric activity of muscles, literally the contraction of muscle fibers, and that control is exerted through the release of acetylcholine. So acetylcholine is working at muscles as well, but we're not focused on that today. We're focused on what we can do during phase one of the day and what we can do during phase two of the day to control the specific neuromodulators, dopamine, epinephrine, serotonin and acetylcholine toward particular end goals. So again, it's really important to understand what the backdrop of these neuromodulators is, the so-called baseline, and that they vary across the day if you're going to be able to leverage tools to optimize your brain chemistry. Before we dive into the more pointed, directed effects of specific tools on neuromodulators, I'd like to just briefly mention hormones because they are also important for understanding the background and the context and these baseline levels of neuromodulators. Hormones have many different effects on the brain and body and not unlike neuromodulators, some of those effects are very fast, some of them are very slow. Today, we want to think about hormones as they relate to these neuromodulators, the dopamine serotonin, epinephrine and acetylcholine. And in general, testosterone tends to collaborate with and increase the action of dopamine. That's not always the case, but in general, when testosterone goes up, dopamine goes up.