David Sinclair on Longevity: What He Has Said About Medication and Supplements

Who Is David Sinclair and Why Does His Regimen Get Attention?

David Sinclair is a Professor of Genetics at Harvard Medical School and co-director of the Paul F. Glenn Center for Biology of Aging Research. His 2019 book Lifespan: Why We Age and Why We Don't Have To brought academic longevity science to a broad audience. Because he openly describes his own supplement and medication use in interviews, podcasts, and on social media, his personal protocol has become one of the most searched longevity regimens online.

That openness creates a specific journalistic and clinical responsibility. Some of what Sinclair takes has meaningful human trial data behind it. Some does not. This article separates the two.

Sinclair's Background and Research Focus

Sinclair's laboratory studies sirtuins, a family of NAD-dependent deacylase enzymes linked to DNA repair and metabolic regulation. His work on SIRT1 activation by resveratrol, published in Nature in 2003, helped launch the field of sirtuin pharmacology [1]. He later extended that work to NAD+ precursors as a way to boost sirtuin activity as cellular NAD+ levels fall with age [2].

Why Researchers Self-Experiment

Self-experimentation by researchers is not new, and Sinclair is candid that his choices are personal and not clinical recommendations. In a 2023 appearance on the Huberman Lab podcast, he stated explicitly that he is "not recommending" his regimen to others and that his choices reflect his own risk tolerance as a researcher who has spent decades reading the primary literature. That distinction matters for anyone reading coverage of his protocol.

NMN: The NAD+ Precursor at the Center of Sinclair's Regimen

Sinclair has consistently cited NMN (nicotinamide mononucleotide) as the compound he is most confident about among his daily supplements. He takes approximately 1 g each morning.

The Biology Behind NAD+ and Aging

NAD+ is a coenzyme required for sirtuin activity, PARP-mediated DNA repair, and mitochondrial energy production. Circulating NAD+ levels decline roughly 50% between young adulthood and age 60 in human tissue samples [2]. NMN is a direct biosynthetic precursor to NAD+ and raises tissue NAD+ concentrations more efficiently than nicotinamide riboside (NR) in some animal models, though head-to-head human data are limited [3].

What Human Trials Show

The largest published placebo-controlled RCT of NMN supplementation enrolled 108 healthy older adults (mean age 65) and randomized them to 250 mg/day NMN or placebo for 12 weeks. Igarashi et al. (2022) reported statistically significant increases in blood NAD+ metabolites and modest improvements in skeletal muscle insulin sensitivity (P<0.05), with no serious adverse events [4]. A separate trial by Yoshino et al. (2021, N=25 postmenopausal women with prediabetes) found that 250 mg/day NMN for 10 weeks raised muscle NAD+ levels and improved insulin signaling gene expression, though no significant change in whole-body insulin sensitivity was observed by hyperinsulinemic clamp [5].

Neither trial used 1 g/day, the dose Sinclair describes. The gap between studied doses (250 mg) and his self-reported dose is worth noting.

Safety Profile to Date

Published trials up to 500 mg/day have not identified significant adverse effects. The FDA granted NMN generally-recognized-as-safe (GRAS) status for doses up to 300 mg/day in 2021, though it later issued a warning letter disputing the pathway used by one manufacturer. NMN is not FDA-approved as a drug [6].

Resveratrol: Sinclair's Earliest and Most Debated Choice

Resveratrol (3,5,4'-trihydroxystilbene) was the compound that made Sinclair's lab famous. He has taken roughly 1 g/day dissolved in a fat source since approximately 2004.

The Science and Its Controversies

Sinclair's 2003 Nature paper showed that resveratrol activated yeast Sir2 (the SIRT1 homolog) and extended yeast lifespan by up to 70% [1]. Subsequent mammalian studies showed resveratrol could extend lifespan in obese mice on high-fat diets. However, Pfizer researchers and others raised concerns in 2010 that some earlier SIRT1 activation findings were artifacts of the fluorescent substrate used in assays [7]. Sinclair's group published rebuttal data using alternative methods, and the debate about the precise mechanism has continued in the literature.

Human Evidence

A 2012 Cochrane-style systematic review of resveratrol in metabolic disease found insufficient evidence to recommend it for any clinical indication [8]. More recent meta-analyses have shown modest, inconsistent effects on fasting glucose, blood pressure, and inflammatory markers. Bioavailability is low (roughly 1% oral bioavailability due to rapid first-pass metabolism), which is why Sinclair takes it with a high-fat food to increase absorption.

The table below outlines a framework for classifying the evidence tier of each compound Sinclair discusses publicly. Editors: insert the original HealthRX Evidence Tier graphic here, ranking each compound from Tier 1 (replicated human RCTs) to Tier 4 (animal/in-vitro only).

Metformin: The Off-Label Longevity Drug With the Most Human Data

Among all compounds Sinclair mentions, metformin has by far the deepest human evidence base, though almost none of it is specifically for longevity rather than diabetes treatment.

Sinclair's Stated Dose and Rationale

Sinclair reports taking 800 mg of metformin at night and skipping it on days when he exercises heavily. The exercise caveat comes from a 2013 study by Sharoff et al. And a 2019 RCT by Konopka et al. (N=53) suggesting that metformin may blunt the mitochondrial adaptations and VO2max improvements normally induced by aerobic exercise training [9].

The TAME Trial and Longevity Rationale

The most direct test of metformin as a longevity drug is the ongoing TAME (Targeting Aging with Metformin) trial, a multicenter RCT funded by the American Federation for Aging Research. TAME is enrolling 3,000 adults aged 65-79 without diabetes to receive 1,500 mg/day metformin or placebo, with the composite primary endpoint of time to a first occurrence of a major age-related disease or death. TAME is expected to complete in 2027 [10].

Observational data supporting metformin's longevity hypothesis include a 2014 analysis by Bannister et al. In Diabetologia (N=78,241) showing that type 2 diabetic patients on metformin monotherapy had lower all-cause mortality than matched non-diabetic controls, a striking finding given that diabetes itself carries mortality risk [11].

Mechanism

Metformin activates AMPK (AMP-activated protein kinase) and inhibits mitochondrial complex I, effects that overlap with caloric restriction signaling. It also inhibits mTORC1 indirectly via AMPK, reduces circulating IGF-1, and has demonstrated anti-inflammatory properties in multiple models [12].

Rapamycin: The mTOR Inhibitor Sinclair Has Discussed More Cautiously

Rapamycin (sirolimus) is the most potent longevity drug in animal models. Sinclair has discussed it publicly but with notably more caution than the compounds above.

Animal Data

The Interventions Testing Program (ITP), a rigorous multi-site NIA-funded program, found that rapamycin extended median lifespan by 9-14% in genetically heterogeneous mice even when treatment began at 20 months of age, equivalent to roughly 60 human years [13]. This remains one of the most reproducible lifespan-extension findings in mammals.

Why Sinclair Is More Guarded

Rapamycin is an FDA-approved immunosuppressant used in organ transplant patients at doses of 2-5 mg/day. At those doses, adverse effects include impaired wound healing, hyperlipidemia, thrombocytopenia, and increased infection risk. Longevity researchers including Matt Kaeberlein (University of Washington) have argued that low intermittent dosing (such as 5-6 mg once weekly) may capture mTOR inhibition benefits while minimizing immunosuppression, but no large RCT has tested this hypothesis in healthy humans [14].

Sinclair has stated in interviews that he "watches the data" on rapamycin but has not consistently confirmed personal use at any specific dose. Any statements about his rapamycin use should be treated as subject to change.

Senolytics: Clearing Zombie Cells

Cellular senescence, the accumulation of non-dividing "zombie" cells that secrete pro-inflammatory signals (the SASP, or senescence-associated secretory phenotype), is one of the hallmarks of aging identified in the Lopez-Otin et al. 2013 Cell framework [15].

Dasatinib Plus Quercetin

The most-studied senolytic combination is dasatinib (a cancer drug, 100 mg) plus quercetin (1,000 mg), administered for two consecutive days every 2-4 weeks. Kirkland et al. At Mayo Clinic conducted a phase 1 trial (N=9) in patients with idiopathic pulmonary fibrosis, showing reduced senescent cell burden in adipose tissue biopsies and improvements in physical function measures after three doses [16]. Sinclair has discussed this combination favorably in public appearances, though he has not confirmed a specific personal dosing schedule.

Fisetin

Fisetin, a flavonoid found in strawberries, has shown senolytic activity in mouse models at doses translating to approximately 20 mg/kg in humans. A small Mayo Clinic pilot (N=40 older adults) found that two consecutive days of high-dose fisetin (20 mg/kg) was safe and produced detectable reductions in plasma inflammatory markers [17]. Human efficacy data remain early-stage.

Vitamin D3, K2, and Aspirin: The Lower-Controversy Additions

Sinclair has mentioned taking vitamin D3 (approximately 4,000-5,000 IU/day), vitamin K2 (MK-7 form, approximately 100-180 mcg/day), and low-dose aspirin (81 mg/day).

Vitamin D Evidence

The VITAL trial (N=25,871, median 5.3-year follow-up) found that vitamin D3 supplementation at 2,000 IU/day did not reduce the primary endpoint of major cardiovascular events or total cancer incidence, though a pre-specified subgroup analysis suggested reduced cancer mortality (HR 0.83, 95% CI 0.67-1.02) that narrowly missed significance [18]. The Endocrine Society's 2024 clinical practice guideline recommends vitamin D supplementation for adults over 75 to reduce mortality risk, citing a dose range of 1,000-2,000 IU/day [19].

Aspirin and Longevity

The ASPREE trial (N=19,114 adults aged 70+) found that aspirin 100 mg/day did not reduce disability-free survival and was associated with higher rates of major hemorrhage compared to placebo (HR 1.38, 95% CI 1.18-1.62) [20]. The U.S. Preventive Services Task Force now recommends against initiating aspirin for primary prevention in adults over 60 [21]. Sinclair's continued aspirin use appears to reflect a personal weighting of evidence that diverges from current USPSTF guidance.

Epigenetic Age Testing: How Sinclair Evaluates His Own Protocol

Sinclair has described using DNA methylation-based epigenetic clocks, primarily the Horvath clock and its successors (GrimAge, PhenoAge), to track his biological age over time. He has stated that his epigenetic age reads approximately 10 years younger than his chronological age, though he acknowledges these are self-reports and not independently verified.

What Epigenetic Clocks Actually Measure

DNA methylation clocks estimate biological age by measuring methylation patterns at hundreds of CpG sites across the genome. Steve Horvath's original 2013 clock (trained on 8,000 samples across 51 tissue types) showed correlation with chronological age of r=0.96 [22]. Newer clocks like GrimAge, published by Lu et al. In 2019, predict time-to-death and healthspan outcomes better than chronological age alone [23].

Limitations of Clock-Based Self-Tracking

Clock readings vary by tissue type, laboratory methodology, and the specific algorithm used. A single blood-based measurement carries a standard error of roughly 3.5 years. Repeated measures over time are more informative than single readings, and no regulatory body has approved epigenetic age as a clinical endpoint. Sinclair acknowledges these limitations in his published work.

What Clinicians Should Know When Patients Ask About This Regimen

Patients increasingly present to primary care and endocrinology appointments asking about Sinclair's protocol. Several practical considerations apply.

Metformin Prescribing Off-Label

Metformin is FDA-approved only for type 2 diabetes and prediabetes prevention (the latter based on the Diabetes Prevention Program, N=3,234) [24]. Prescribing it for longevity in a non-diabetic patient is off-label. Some clinicians operating within functional or longevity medicine frameworks do prescribe it this way, but patients should understand this status clearly.

Drug Interactions

Resveratrol inhibits CYP3A4 and CYP2C9 at high doses and could theoretically raise plasma levels of warfarin, statins, and certain anticoagulants. Dasatinib (if used as a senolytic) carries its own interaction profile as a BCR-ABL inhibitor. A full medication review is needed before adding any of these compounds.

Exercise Interaction With Metformin

The Konopka et al. 2019 RCT (N=53, 12-week aerobic training program) found that older adults randomized to metformin showed significantly smaller improvements in VO2max (+3.7% metformin vs. +6.9% placebo, P<0.05) and attenuated mitochondrial respiration gains compared to placebo [9]. Sinclair's strategy of skipping metformin on heavy exercise days is a direct response to this finding, though whether this timing optimization preserves full exercise adaptation has not been tested in a controlled trial.

Summary of Sinclair's Publicly Stated Regimen

| Compound | Sinclair's Stated Dose | Primary Evidence Level | Regulatory Status | |---|---|---|---| | NMN | 1 g/day (morning) | Small human RCTs (250 mg doses) | Investigational / dietary supplement | | Resveratrol | 1 g/day (with fat) | Mixed human data, mechanism debate | Dietary supplement | | Metformin | 800 mg/day (night) | Extensive T2D trials; TAME ongoing | Off-label for longevity | | Rapamycin | Not confirmed at specific dose | Strong mouse data; limited human safety data | Off-label / transplant drug | | Dasatinib + Quercetin | Not confirmed at specific schedule | Phase 1 human senolytic data | Dasatinib: off-label; Quercetin: supplement | | Vitamin D3 | ~4,000-5,000 IU/day | VITAL trial; Endocrine Society guidelines | OTC supplement | | Aspirin | 81 mg/day | ASPREE shows no primary-prevention benefit over 60 | OTC; USPSTF recommends against |