Andrew Huberman· PhD
so um I have used again rodol in a lot of situations because the other thing you kind of have to pay attention to the cortisol is is you have it's supposed to be modulated throughout the day it's not supposed to be at this normal value in fact if you look at normative values um it's typically uh described in um uh micrograms per deciliter and depending on literally what company you used to draw your blood if you're getting it through the blood uh depending on which method they use to analyze it the normative values are like frankly embarrassingly all over the place um they're mostly going to be like 5 to 25 as a quote unquote normative value but that's outrageous we also know those numbers vary massively by age by sex um and throughout the day and so if you only are taking a single point let's assume you're doing a fasted blood draw which is what most folks do it's really only going to tell you a lot about what's happening in that moment we need to know well like maybe let's say my cortisol was if I'm a say 38-year-old woman and my 7 A.M cortisol was you know 15 milligram per decer that's pretty good but if it's 15 milligrams per deciliter at 3 p.m. oh boy I'm I'm probably having some issues right so there's a change throughout the day and you need to be able to plot that curve so you can actually well pretty standard practice that we do is we look at cortisol throughout the day we're going to take multiple markers because I don't want to just see your Baseline cortisol I want to see this curve throughout the day that's going to tell me a ton about U again is your sleep being caused by this regulation um is it your training is it something else so I would like take a single Baseline blood marker of cortisol with a lot of grain of salt we we typically measure it at least three times throughout the day so something like 6:00 to 9:00 a.m. 12: to 3 and then something like closer to the evening oftentimes we do much more we'll do like seven points or something like that throughout the day depending on the situation so you want to be careful of that um just since we're here you can also get cortisol in uh through saliva and now there's sort of pros and cons to that because the the pro of doing it in your blood is it's it it's much more stable um saliva is extremely responsive to whatever happened these seconds before you took that test the upside of it though is you can do a bunch of real world life experiments so for example we will do this sometimes if we want to see how an individual is responding to a given stressor let's take it right let's take the take it in the you know spit into a tube we're going to take it and then we're going to go do this workout or this cold exposure whatever we're going to do take it at thean we know that it's responsive to what just happened but that's the point um so you can actually there's sort of pros and cons so you'll use the appropriate measure for the appropriate uh question you're trying to answer yeah a couple of points and Reflections about cortisol my first laboratory Duty as an undergraduate was in a was actually in a biopsychology lab at the time they didn't have the field of Neuroscience as it's now called it was called biopsychology or psychobiology I didn't know that no there was used to be neurochemistry neurobiology they had all collapsed into what we now called Neuroscience which was only some years ago but my job was to collect cortisol samples which means I I was collecting um spit which means I was collecting saliva and the an advantage of saliva based cortisol it's free cortisol it's the active form as you mentioned it's reflective of what happened in the seconds or minutes just prior a couple of things about the regular cortisol pattern across the day because I realized that while it wonderful for everybody to get their cortisol measured in detail multiple times and blood and and saliva and so on some people just won't do that for whatever reason or can't do that yeah and the basic Contour of a healthy pattern of cortisol secretion is to have highest levels of cortisol in the morning is actually part of the mechanism that's associated with waking you up