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The Biology of Slowing & Reversing Aging | Dr. David Sinclair

In this episode, I am joined by Dr. David Sinclair, tenured professor of genetics at Harvard Medical School and an expert researcher in the field of longevity. Dr. Sinclair is also the author of the book Lifespan: Why We Age & Why We Don't Have To and the host of the Lifespan podcast, which launches January 5, 2022. In this interview, we discuss the cellular and molecular mechanisms of aging and what we all can do to slow or reverse the process. We cover fasting and supplementation with resveratrol, NAD, metformin and NMN. We also explore the use of caffeine, exercise, cold exposure and why excessive iron load is harmful. Further topics include food choices for offsetting aging and promoting autophagy (clearance of dead cells) and the key blood markers everyone should monitor to determine biological versus chronological age. We look ahead to the future of longevity research and technology. This episode includes extensive basic science and specific, actionable protocols, right down to the details of what to do and when. By the end, you will have in-depth knowledge of the biology of aging and how to offset it. For an up-to-date list of our current sponsors, please visit our website: https://www.hubermanlab.com/sponsors. Previous sponsors mentioned in this podcast episode may no longer be affiliated with us. Dr. David Sinclair Links: Lifespan Podcast: https://lifespanpodcast.com Twitter: https://twitter.com/davidasinclair Instagram: https://www.instagram.com/davidsinclairphd/ YouTube: https://www.youtube.com/davidsinclairpodcast Lifespan (book): https://amzn.to/47MLimC Aging Test Waitlist: https://www.tallyhealth.com Harvard Lab Website: https://sinclair.hms.harvard.edu Social: Instagram - https://www.instagram.com/hubermanlab Twitter - https://twitter.com/hubermanlab Facebook - https://www.facebook.com/hubermanlab Website - https://hubermanlab.com Newsletter - https://hubermanlab.com/neural-network Timestamps: 00:00:00 Dr. David Sinclair, Harvard Medical School 00:03:30 ROKA, InsideTracker, Magic Spoon 00:07:45 “Aging as a Disease” vs. Longevity & Anti-Aging 00:10:23 What Causes Aging? The Epigenome 00:15:53 Cosmetic Aging 00:17:15 Development Never Stops, Horvath Clock 00:20:12 Puberty Rate as a Determinant of Aging Rate 00:23:00 Fasting, Hunger & Food Choices 00:32:44 Fasting Schedules, Long Fasts, (Macro)Autophagy 00:34:50 Caffeine, Electrolytes 00:35:56 Blood Glucose & the Sirtuins; mTOR 00:37:55 Amino Acids: Leucine, “Pulsing” 00:44:35 Metformin, Berberine 00:50:29 Resveratrol, Wine 00:53:20 What Breaks a Fast? 00:56:45 Resveratrol, NAD, NMN, NR; Dosage, Timing 01:09:10 Are Artificial Sweeteners Bad for Us? 01:12:04 Iron Load & Aging 01:15:05 Blood Work Analysis 01:19:37 C-Reactive Protein, Cholesterol: Serum & Dietary 01:26:02 Amino Acids, Plants, Antioxidants 01:33:45 Behaviors That Extend Lifespan, Testosterone, Estrogen 01:40:35 Neuroplasticity & Neural Repair 01:46:19 Ice Baths, Cold Showers, “Metabolic Winter” 01:48:07 Obesity & How It Accelerates Aging, GnRH 01:52:10 Methylation, Methylene Blue, Cigarettes 01:56:17 X-Rays 01:59:00 Public Science Education, Personal Health 02:05:40 The Sinclair Test You Can Take: www.doctorsinclair.com 02:08:13 Zero-Cost Support & Resources, Sponsors, Patreon, Supplements, Instagram The Huberman Lab Podcast is for general informational purposes only and does not constitute the practice of medicine, nursing or other professional health care services, including the giving of medical advice, and no doctor/patient relationship is formed. The use of information on this podcast or materials linked from this podcast is at the user’s own risk. The content of this podcast is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Users should not disregard or delay in obtaining medical advice for any medical condition they may have and should seek the assistance of their health care professionals for any such conditions.

Andrew HubermanhostDavid Sinclairguest
Dec 26, 20212h 10mWatch on YouTube ↗

At a glance

WHAT IT’S REALLY ABOUT

Harvard Geneticist Reveals How To Slow, Halt, And Reverse Aging

  1. Andrew Huberman interviews Harvard geneticist Dr. David Sinclair about the modern science of aging, why he classifies aging as a disease, and how it can be slowed or even reversed. Sinclair explains the central role of the epigenome—cellular information that controls gene expression—in driving aging, and describes how damage to that system accumulates like scratches on a CD. They detail how behaviors such as intermittent fasting, exercise, and cold exposure, plus compounds like resveratrol, NMN, and metformin, can activate longevity pathways (sirtuins, mTOR, NAD) and improve biological age. The conversation also covers practical protocols, measurement tools (blood work, epigenetic clocks), emerging gene therapies to reverse cellular age, and Sinclair’s broader vision for personalized, preventative longevity medicine.

IDEAS WORTH REMEMBERING

5 ideas

Aging behaves like a disease driven largely by loss of epigenetic information, and treating it as such opens the door to prevention and reversal.

Sinclair argues the classical definition that ‘disease’ must affect less than 50% of people arbitrarily excludes aging, even though aging causes 80–90% of heart disease, Alzheimer’s, and many cancers. His lab’s work supports the idea that if you reverse cellular age—by restoring proper epigenetic regulation—age-related diseases diminish or resolve in animal models. This reframing justifies targeting aging itself instead of only treating late-stage diseases with “Band-Aids.”

The epigenome—not just genes—controls how fast you age, and it’s modifiable by lifestyle.

DNA is like the fixed music on a CD, while the epigenome is the player deciding which “songs” (genes) run in which cells. Over time, environmental stress (DNA breaks, metabolic stress) creates “scratches” in this system: genes turn on in the wrong cells or turn off when they shouldn’t, leading to loss of cell identity and function. About 80% of future health and longevity, Sinclair says, is determined by this epigenetic control system, which is influenced by diet, activity, and other behaviors rather than hardwired genetics.

When you eat may matter more for longevity than what you eat.

Animal studies across decades show that reducing eating windows—without necessarily reducing total calories—extends lifespan and healthspan significantly. Mice that consumed all their calories in a 1-hour window daily lived dramatically longer, regardless of macronutrient ratios, compared to mice eating ad libitum. Sinclair’s core behavioral recommendation is to compress eating into a shorter daily window (e.g., skipping breakfast or dinner), leveraging longer fasting periods to lower insulin/glucose, activate sirtuins, and downregulate mTOR.

Periodic stressors (fasting, cold, exercise) are beneficial because they turn on longevity pathways, but they work best in pulses, not constantly.

Sinclair emphasizes hormesis: brief, manageable stress stimulates cellular defense programs. Fasting, low amino acid intake, cold exposure, and exercise converge on pathways like sirtuins (activated by low insulin/glucose and high NAD) and mTOR (downregulated by low leucine/isoleucine/valine). His data suggest pulsing stressors and even pulsing supplements (e.g., resveratrol every other day in mice) can produce greater benefits than chronic, unbroken exposure, mimicking natural feast–famine cycles and avoiding over-suppression of growth.

Boosting NAD and activating sirtuins with NMN, resveratrol, and lifestyle may improve cellular repair and metabolic health with aging.

NAD, essential for over 400 reactions, declines with age and obesity due to reduced synthesis and increased degradation (via CD38). Sirtuins, which repair DNA and maintain epigenetic integrity, require NAD and are further activated by molecules like resveratrol. Sinclair takes ~1 g/day of resveratrol with fat and ~1 g/day of NMN in the morning; unpublished trials he cites show this roughly doubles NAD levels in humans after two weeks. Exercise and fasting also raise NAD and sirtuin activity, and preliminary data in animals show improved endurance and vascular function.

WORDS WORTH SAVING

5 quotes

Aging is 80 to 90 percent the cause of heart disease, Alzheimer’s. If we didn’t get old and our bodies stayed youthful, we would not get those diseases.

David Sinclair

I think aging is a loss of information in the same way that when you Xerox something a thousand times, you’ll lose that information.

David Sinclair

If there’s one thing I could say, I would say definitely try to skip a meal a day.

David Sinclair

What we found is that it’s not as important what you eat, it’s when you eat during the day.

David Sinclair (describing mouse time-restricted feeding study)

My view of longevity is: I don’t burn both ends of the candle. I have one end of the candle lit, and I’m very careful. I don’t blow on it.

David Sinclair

Aging as a disease vs. normal aging; hallmarks of aging and epigenome theoryEpigenetics, DNA methylation, and Sinclair’s information-loss model of agingIntermittent fasting, caloric restriction, and food timing for longevityLongevity pathways: sirtuins, NAD, mTOR, AMPK and their nutritional/pharmacologic activatorsSupplements and drugs: resveratrol, NMN vs. NR vs. B3, metformin, berberineHormones, growth signals, body size, and their impact on lifespanMeasurement and monitoring: blood biomarkers, CRP, cholesterol, glucose, biological age clocks

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