Huberman Lab

Dr. Chris McCurdy on Huberman Lab: Why Kratom Misleads

How kratom alkaloids differ across leaf, extract, and isolate forms; McCurdy maps opioid and serotonin effects, addiction risk, and harm reduction tools.

AHAndrew HubermanhostCMDr. Chris McCurdyguest

Jul 21, 2025·2h 42m·Watch on YouTube ↗

📖 CHAPTERS

1. 1
   0:00 – 7:10

   Introduction and Framing: Why Kratom Matters Now

   Huberman introduces Dr. Chris McCurdy, his background in medicinal chemistry, and sets the agenda: understanding kratom’s mechanisms, benefits, risks, and how Western products differ from traditional use. They preview key topics such as addiction risk, kratom’s role in opioid transition, and how plant alkaloids have shaped modern medicines and even soft drinks.

2. 2
   7:10 – 27:20

   Traditional Kratom: The Leaf, The Tree, And Rural Use

   McCurdy explains what kratom is biologically and culturally: a Southeast Asian tree whose leaves are chewed or boiled into a tea by rural laborers for stamina, mood elevation, and social relaxation. He describes the classic dose-dependent profile—stimulant at low doses, sedative/euphoric at higher doses—and how anecdotal reports of using kratom to stave off opioid withdrawal first drew his research interest.

3. 3
   27:20 – 44:30

   From Tree to Shot: Western Kratom Products and Dose Pitfalls

   The discussion shifts to U.S. kratom products: dried leaf powders, capsules, and especially concentrated ‘energy shots’ and tonics. McCurdy explains how pre-extraction into liquids changes pharmacokinetics, allowing much faster and higher absorption compared to eating leaf or tea, and why unlabeled or misunderstood serving sizes create serious overdose and dependence risks, especially for youth.

4. 4
   44:30 – 52:00

   Who Uses Kratom in the U.S. and Why?

   Drawing on survey and ecological momentary assessment data, McCurdy outlines major user groups and motivations. Most self-selected respondents report using kratom responsibly for energy, mood, and pain rather than euphoria; a subset use it as pre/post-workout support; and another subset uses it socially for intoxication. He also notes that estimated daily users likely exceed 20 million in the U.S.

5. 5
   52:00 – 1:07:00

   Dependence, Tolerance, and Youth Risk

   They dig into physical dependence: how daily users can experience caffeine-like withdrawal symptoms from leaf products, and how higher-potency preparations can produce more opioid-like withdrawal profiles. McCurdy strongly advises age limits due to unknown impacts on developing brains and warns about kids inadvertently buying kratom shots in gas stations.

6. 6
   1:07:00 – 1:19:00

   Plant Alkaloids 101: How Nitrogen-Containing Molecules Hit Our Brains

   McCurdy explains what alkaloids are chemically and why nitrogen atoms make them so biologically active. Using dopamine, serotonin, nicotine, morphine, and cocaine as examples, he describes how charged nitrogens act like ‘tractor beams’ to bind protein receptors, and how natural products historically revealed entire neurotransmitter systems before their endogenous ligands were known.

7. 7
   1:19:00 – 1:49:30

   Nature, Medicine, and the Problem of Concentration

   The conversation broadens to natural vs. synthetic medicines, emphasizing that most modern drugs descend from plant or animal products. Huberman and McCurdy discuss aspirin from willow, GLP‑1 analogues from Gila monster saliva, metformin/berberine, and how industrial extraction and marketing (sugar, processed foods, cannabis edibles, etc.) transform subtle natural tools into potent, sometimes harmful, agents.

8. 8
   1:49:30 – 2:02:00

   Kratom’s Multi-System Mechanism: Opioid, Serotonin, and Adrenergic Targets

   McCurdy details kratom’s known pharmacology. Rather than being a ‘pure opioid,’ whole kratom contains dozens of alkaloids, some mildly opioid, others strongly serotonergic or adrenergic. He frames whole-plant kratom as a tri-pronged analgesic—simultaneously engaging opioid, serotonin, and adrenergic systems—in a way no approved single drug or cocktail currently does, which may explain why some users get strong pain relief without heavy intoxication.

9. 9
   2:02:00 – 2:10:20

   The Dark Edge: 7‑Hydroxymitragynine and Respiratory Depression

   Here McCurdy draws a sharp line between whole-plant kratom and kratom-derived isolates, focusing on 7‑hydroxymitragynine, a potent mitragynine metabolite now synthesized and sold directly. His lab’s recent animal work shows this compound can cause opioid-level respiratory depression reversible by naloxone, making these products functionally akin to strong opioids despite ‘natural’ branding.

10. 10
    2:10:20 – 2:35:20

    Kratom, Alcohol, and Polydrug Concerns

    They touch on kratom–alcohol interactions and harm reduction potential. While formal interaction studies are scarce, anecdotal reports suggest kratom can reduce alcohol desire or intake. NIAAA is now funding studies on kratom for alcohol use disorder, but McCurdy cautions that mixing kratom (especially opioid-like isolates) with heavy drinking could plausibly magnify respiratory risks, as seen with opioid–alcohol combinations.

11. 11
    2:35:20 – 2:53:20

    Getting Off Kratom: Clinical Realities and Unknowns

    In response to listener concerns about dependence, McCurdy describes addiction physicians using buprenorphine or methadone to transition kratom-dependent patients, but questions whether treating a multi-system agent with pure opioids is optimal. He underscores that there is no standardized protocol for kratom cessation and stresses the importance of medical supervision and psychosocial support rather than DIY tapering with other drugs.

12. 12
    2:53:20 – 3:21:40

    Coca Leaf, Cacao, and the Soft Drink Pharmacology Backstory

    The episode widens to other plant medicines. McCurdy discusses coca leaf as a nutritious, non-abuse-prone traditional plant that was overshadowed by purified cocaine; cacao’s theobromine and mood effects; and the pharmacologic origins of Coca‑Cola, Pepsi, 7UP, and Dr Pepper. He explains how Coca‑Cola still legally imports coca leaf, removes cocaine for pharmaceutical use, and uses the de-cocainized extract as a flavoring agent.

13. 13
    3:21:40 – 3:51:00

    McCurdy’s Path: From Pharmacy Counter to Natural Products Chemist

    In the final segment, McCurdy shares his personal journey: from underperforming high school student to pharmacist, then PhD student and medicinal chemist specializing in natural products. He recounts how work on nicotine-like compounds for Alzheimer’s and on Salvia divinorum’s kappa-opioid hallucinogen led him to kratom’s underexplored literature, particularly a shelved 1970s SmithKline & French program on mitragynine.

14. 14
    3:51:00

    Closing Reflections: Nuance, Regulation, and Public Education

    The episode closes with Huberman summarizing key distinctions—leaf vs. isolate, youth vs. adult, harm reduction vs. recreational use—and praising McCurdy’s nuanced, evidence-driven approach. McCurdy reiterates that kratom has real therapeutic potential and real harms, insisting on better labeling, categorization, and clinical research, plus public education, rather than simplistic ‘good’ or ‘bad’ narratives.