Andrew Huberman (solo): Professor of neurobiology and ophthalmology at Stanford School of Medicine and host of the Huberman Lab podcast. This is a solo Essentials episode revisiting his thyroid and growth hormone material.
What this episode covers
This Huberman Lab Essentials episode covers the two hormone systems Huberman argues most strongly set overall metabolism: thyroid hormone and growth hormone. He walks through the brain-pituitary-gland signaling chain, explains what T3 and T4 do, and details the nutrients needed for healthy thyroid function: iodine, selenium, and L-tyrosine. For growth hormone, he describes how it is released during early slow-wave sleep and how exercise, low blood glucose, arginine, body temperature, and sauna can dramatically increase it. He also touches on the age-related decline in growth hormone and the emerging, riskier world of peptides like sermorelin.
Recommended on this episode
Altered Traits: Science Reveals How Meditation Changes Your Mind, Brain, and Body
Daniel Goleman and Richard Davidson
“the book is called altered traits ... it's an excellent book ... very interesting book for those of you that are interested in meditation”— Andrew Huberman
Also referenced (named, not recommended)
Iodine
various
“the thyroid needs iodine in order to produce thyroid hormone iodine combines with an amino acid that we've talked about before called el tyrosine”— Andrew Huberman
Selenium
various
“you also need something else which is called selenium selenium is important in order for thyroid hormone to be made”— Andrew Huberman
L-Tyrosine
various
“you absolutely need sufficient iodine you need sufficient El tyrosine and then you also need something else which is called selenium”— Andrew Huberman
Arginine
various
“the amino acid arginine can increase growth hormone levels substantially ... taking Arginine can dramatically increase growth hormone release 400 to 600% above baselines”— Andrew Huberman
Sermorelin
various (prescription)
“people now will take things like ... sermorelin which is not the entire peptide sequence of growth hormone releasing hormone but it's a subset”— Andrew Huberman
Big reveals from this episode
- Sauna (20 min hot, 30 min cooling, 20 min hot, repeated over three days) has been shown to increase growth hormone release up to 16-fold (1600%).
- Resistance or endurance exercise of ~60 minutes can raise growth hormone 300-500%, both immediately and the following night.
- Arginine, by mouth or vein, can boost growth hormone 400-600% above baseline, but more than ~9 grams actually blunts the effect.
- Combining arginine with exercise does NOT stack: growth hormone stays clamped around 300-500% instead of adding up.
- Eating within two hours of sleep suppresses growth hormone release because elevated insulin and glucose block it.
- Between ages 30 and 40 nightly growth hormone output drops two- to three-fold, but exercise and sleep habits can fully offset the decline.
- Huberman warns that excess heat is genuinely dangerous; it doesn't take much of a brain temperature rise to kill neurons and cause death from hyperthermia.
Worth remembering
- You can basically forget about T4; T3 is the more active thyroid hormone.
- Brazil nuts are the 'heavyweight champion' for selenium: six to eight contain about 550 micrograms.
- Recommended daily selenium varies by country, averaging around 155 micrograms; most people don't get enough.
- Growth hormone is released in the early part of sleep during slow-wave (deep) sleep, gated by delta-wave brain activity.
- Certain meditation can put the brain into states that mimic slow-wave sleep, potentially aiding growth hormone release.
- A sugary sports drink during exercise immediately flatlined growth hormone levels in studies.
- A proper ~10-minute warm-up that actually warms the body helps maximize the growth hormone response to exercise.
- Too-high growth hormone grows all tissues, including heart, lungs, liver, and spleen, which is the danger of abuse.
- Continuously injected peptides can switch on long-lived gene expression programs that may even feed tumor growth.