Health Effects & Risks of Kratom, Opioids & Other Natural Occurring Medicines | Dr. Chris McCurdy

**Andrew Huberman** (0:00)
Welcome to the Huberman Lab Podcast, where we discuss science and science-based tools for everyday life.
I'm Andrew Huberman, and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. My guest today is Dr. Chris McCurdy. Dr. Chris McCurdy is a professor of medicinal chemistry at the University of Florida, where he directs research on natural products and their pharmacologic effects. Most recently, the plant-derived compound kratom, which is readily sold in the US and around the world and is now used by tens of millions of people daily. And those numbers are increasing fast. Dr. McCurdy's research focuses on understanding how kratom interacts with our nervous system and affects our physiology and behavior. He also studies its potential for addiction. During today's episode, we discuss the complex effects of kratom and its relationship to the opioid system. Dr. McCurdy explains how kratom's active compounds work in the brain, why it shares certain similarities to opioid drugs, and critically, how kratom products available in the US and elsewhere are largely derivatives and isolates of the kratom leaf, which is very different in terms of the effects it produces when compared to the traditional leaf products. And unfortunately, that has confused and in many cases harmed consumers. So today, you'll learn about kratom's effects at different doses. And when it's sourced in different ways, you'll learn about how it can be a stimulant, how it can increase focus, how it can be a painkiller, how it can increase euphoria, but also its strong potential for addiction. You'll also learn what is known about kratom in terms of its ability to help people transition off traditional opioid drugs. It has been shown to be effective for that. However, we are also going to explain the potential harms of kratom, in particular in young people whose brains are still developing and in people that don't have a prior opioid addiction. Our discussion about kratom also opens up a broader discussion about other plant alkaloids that have medicinal properties, including those found in things like cocoa and 100% chocolate. And we discussed the incredible history of soft drinks like Coca-Cola, Pepsi, 7Up and Dr. Pepper, which believe it or not were originally developed as pharmacologic tools before becoming the ultra-popular beverages that we're familiar with today. So I realize many people have heard about kratom, but also many of you perhaps have not. What everyone should know, however, is that kratom products are pretty much everywhere now. You can find them in supermarkets, convenience stores, online, and they're sold under the pretense of having very specific effects related to energy, pain management or mood. But by the end of today's episode, you'll have a thorough understanding of how this plant compound actually works. Yes, it's potential effects, but also it's serious risks. Before we begin, I'd like to emphasize that 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. In keeping with that theme, today's episode does include sponsors. And now for my discussion with Dr. Chris McCurdy. Dr. Chris McCurdy, welcome.

**Chris McCurdy** (2:53)
Thank you, it's really a pleasure to be here.

**Andrew Huberman** (2:55)
I'm excited to have you here because you work on some incredibly interesting compounds, several of which are very controversial, and all of which are impacting health and society in a major way right now, especially in the United States. The most notable of those is kratom. I'm guessing some people have heard of kratom. I'm guessing some people perhaps have not. I'm pretty certain everyone has seen a kratom product because they are everywhere. But it's often in the fine print. So could you just tell us what kratom is, where it's found in nature and in the United States, and some of its properties that people take it in order to achieve certain effects, and maybe some of its lesser known properties. So that's a lot of questions. So maybe just a general description of kratom, where it's found and what it does.

**Chris McCurdy** (3:46)
Let's just start from the beginning and make it easy. It's a tree that's called Mitragana speciosa by its botanical name. It's called kratom in Southeast Asia, which is where it's native to. It's actually native to where Peninsula Malaysia and Thailand connect. So at the border of those two countries, it's thought to be ground zero for where this tree species came from. In that region, it's very rural. It's lots of farmers and lots of outdoor laborers, and those outdoor laborers chew the leaves in Thailand, or they make a tea, more technically what we call a de-coction, because they boil the leaves for hours. But they'll harvest fresh leaves and boil those leaves, and then drink that, just like we would drink a coffee drink in the morning, to give them energy, to give them sort of sustainability throughout the day, to tolerate that heat, humidity, and very harsh tropical environment. And it gives them this stamina to make it through the day. And that's really what the traditional use has always been, more or less for energy and to get through that day. But it also has been used to treat pain. It's been used to treat, of all things, erectile dysfunction. It's been said to be nature's sort of viagra.