In this episode, I interview Dr. Robert Sapolsky, Ph.D., Professor of Biology, Neurology & Neurosurgery at Stanford University. We discuss stress, what defines short-term versus long-term stress, and how stress can be beneficial or detrimental, depending on the context. We also discuss stress mitigation and how our sense of control over stress mitigation techniques, including exercise, determine health outcomes. Dr. Sapolsky explains some of the key effects of the hormone testosterone — how it can amplify pre-existing tendencies for aggression or sexual behavior, but that it does not produce those behaviors per se. He also explains how testosterone impacts our social hierarchies, sense of confidence, and willingness to embrace challenges of different kinds. He also explains how our behaviors and perceptions shape testosterone levels. And we discuss estrogen and the powerful role it plays in brain development, health and longevity. Finally, we discuss free will, what it means to have free will, and if we have any free will, including how knowledge alone might allow us to make better decisions for ourselves and society.  For the full show notes, visit hubermanlab.com. Thank you to our sponsors AG1 (Athletic Greens): https://athleticgreens.com/huberman LMNT: https://drinklmnt.com/huberman Thesis: https://takethesis.com/huberman Supplements from Momentous https://www.livemomentous.com/huberman Timestamps (00:00:00) Introduction: Dr. Robert Sapolsky  (00:02:25) Sponsors: AG1, LMNT, Thesis, Momentous (00:06:30) Stress: Short & Long-Term, Good & Bad  (00:09:11) Valence & Amygdala  (00:11:00) Testosterone: Common Myths vs. Actual Truths  (00:15:15) Behaviors that Affect Testosterone   (00:17:20) Mindsets & Contexts that Affect Testosterone (00:20:28) How Finger Length Ratios Reflect Prenatal Hormone Levels   (00:22:30) Aggression: Male-Female, Female-Male, & Female-Female  (00:24:05) Testosterone: The Challenge Hypothesis  (00:29:20) How Dopamine Impacts Testosterone & Motivation  (00:32:32) Estrogen: Improves Brain & Longevity BUT TIMING IS KEY  (00:39:40) Are Testosterone & Sperm Counts in Males Really Dropping?  (00:42:15) Stress Mitigation & Our Sense of Control  (00:51:35) How Best to Buffer Stress  (00:57:04) Power of Perception, Choice & Individual Differences  (01:00:32) Context-Setting, Prefrontal Cortex & Hierarchy  (01:11:20) How Dr. Sapolsky Accomplishes Deep Thinking   (01:13:17) Do We Have Free Will?  (01:20:50) How to Apply Knowledge & Learning   (01:23:44) Robert’s New Book: “Determined: The Science of Life Without Free Will”  (01:28:27) Reflections, Support of Podcast, & Supporting Stress Research  Title Card Photo Credit: Mike Blabac Disclaimer