David Sinclair, the Harvard geneticist, has done more to popularize a specific longevity supplement stack than anyone else in biohacking. His personal protocol — nicotinamide mononucleotide (NMN), resveratrol, and trimethylglycine (TMG) — has been repeated on hundreds of podcasts and is now sold by dozens of brands. The stack drives real consumer demand and real consumer spending.
Vyvata does not currently stock these compounds. That is deliberate. The evidence for the human lifespan claims is thinner than the marketing implies, the manufacturing quality across brands is genuinely uneven, and the FDA has been actively reclassifying NMN in ways that make the retail landscape unstable. This article is a brand-agnostic walk through the biochemistry, the studies people cite, the studies people avoid citing, and the honest cost calculus for someone deciding whether to run the stack anyway.
What the stack is
Sinclair's publicly discussed morning protocol has varied over the years, but the core three compounds are consistent.
- NMN (nicotinamide mononucleotide) — typically 1 gram per day, taken with yogurt or an oil-based food to help absorption. NMN is a precursor to NAD+, a coenzyme central to cellular metabolism.
- Resveratrol — typically 1 gram of trans-resveratrol per day, taken with fat. Resveratrol is a polyphenol from grape skins that activates sirtuins in some experimental systems.
- TMG (trimethylglycine, also called betaine) — typically 500 mg to 1 gram per day. TMG donates methyl groups and is included to offset the methylation burden of high-dose NMN or NR supplementation.
Sinclair has been public that this is his own experimental regimen, not a clinical recommendation. That distinction gets flattened in the podcast ecosystem. It is worth restating up front.
The NAD+ story: real biology, uncertain intervention
The biochemical premise is well established. NAD+ (nicotinamide adenine dinucleotide) is a coenzyme required by hundreds of enzymes involved in energy production, DNA repair, and gene regulation. NAD+ levels decline with age in most tissues studied. Sirtuins, a family of enzymes implicated in stress-response and longevity, are NAD+ dependent. The chain of reasoning behind the stack is: restore NAD+, reactivate sirtuins, slow age-related dysfunction.
Each step of that chain is more solid than the next. The NAD+ decline is real. That sirtuins are NAD+ dependent is basic biochemistry. Whether raising NAD+ in a middle-aged human actually alters aging biology in a meaningful way is where the evidence gets thin.
NMN: the bioavailability fight
Yoshino and colleagues (2021, Science) published one of the most-cited human NMN trials — a randomized, placebo-controlled study in postmenopausal women with prediabetes showing improved muscle insulin sensitivity after 10 weeks of 250 mg NMN daily. That is a real, positive human result. It is also 250 mg per day, in a specific population, for a metabolic endpoint, over ten weeks. It is not a lifespan trial.
The oral bioavailability of NMN is genuinely contested. NMN is a large, polar molecule and the intestinal wall has been shown in mouse work by Grozio and colleagues (2019) to convert NMN into nicotinamide riboside (NR) before absorption, via a specific transporter (Slc12a8) whose role in humans is still debated. Multiple critics — including researchers with no dog in the branded-supplement fight — have pointed out that in some human pharmacokinetic studies, serum NMN barely rises after oral dosing, while nicotinamide (the plain NAD+ precursor found in a can of tuna) rises reliably. If most oral NMN is being converted to something else before it enters the bloodstream, the branded premium for NMN over cheaper NAD+ precursors is hard to justify.
Downstream NAD+ measurements are what actually matter for the stated goal. Some studies do show increases in blood NAD+ metabolites after NMN supplementation. Whether that translates to increased NAD+ in the tissues where you would want it — muscle, brain, liver — is a much harder question and one the current human literature has not answered.
The FDA in 2022 issued a determination that NMN could no longer be marketed as a dietary supplement, on the grounds that it had been authorized for investigation as a drug. Enforcement has been inconsistent and many brands continue to sell it, but the regulatory ground is not stable.
Resveratrol: a controversial history
Resveratrol is the most-studied and most-embarrassed compound in the stack. The story runs through Sirtris Pharmaceuticals, the company Sinclair co-founded and sold to GlaxoSmithKline in 2008 for roughly $720 million.
Shortly after the acquisition, allegations surfaced questioning some of the underlying data suggesting resveratrol activated sirtuins in the specific way the marketing implied. Subsequent independent work by Pacholec and colleagues (2010) argued that the original assay artifact — a fluorescent tag added to the test peptide — was the actual reason resveratrol appeared to activate SIRT1, and that the effect vanished with a natural substrate. GSK ultimately shuttered Sirtris in 2013. The company had never brought a resveratrol-based drug to market.
None of that means resveratrol does nothing. It is a real polyphenol with real antioxidant activity and some genuinely interesting biology in animal models. What it means is that the specific mechanism used to justify the human protocol — direct sirtuin activation — has been substantially walked back in the peer-reviewed literature. Human trials of resveratrol for metabolic endpoints have produced mixed results, with small effects at best.
Poulsen and colleagues (2013) ran a randomized placebo-controlled trial of 1.5 g resveratrol daily in obese men with metabolic syndrome. They found no significant improvement in insulin sensitivity, blood pressure, or inflammatory markers versus placebo. That is a real, negative human trial on a Sinclair-style dose in a relevant population. It does not close the question, but it is the study people who cite the mouse data tend to skip.
TMG: the reason to include it
TMG is the least controversial part of the stack because its purpose is defensive rather than active. Both NMN and its cousin NR are methylated by the enzyme NNMT before excretion, using S-adenosyl methionine (SAM) as the methyl donor. At the gram-per-day doses Sinclair discusses, that methylation burden is not trivial. Depleting SAM can raise homocysteine, a cardiovascular risk marker.
TMG (trimethylglycine, chemically identical to the betaine sold as a separate supplement) donates methyl groups and helps regenerate methionine from homocysteine. Adding it alongside high-dose NAD+ precursors is a reasonable precaution grounded in known metabolism. This is the one part of the protocol where the mechanistic case is clean.
TMG itself has been used at 1.5 to 6 grams per day in cardiovascular research for decades and has a good safety profile at those doses. Side effects at high doses are typically gastrointestinal.
Mouse to human: the historical track record
This is the part of any longevity supplement conversation that deserves the most sober treatment. The track record of translating lifespan-extending mouse compounds into humans is, historically, brutal.
The Interventions Testing Program (ITP), funded by the National Institute on Aging, is the closest thing gerontology has to a rigorous pipeline for testing candidate lifespan compounds in mice under standardized conditions across multiple sites. Of the dozens of compounds tested, only a handful have reliably extended lifespan in mice — rapamycin being the most famous. Neither resveratrol nor NMN has produced the ITP-tier evidence rapamycin has.
Even for rapamycin — which does extend mouse lifespan reproducibly — the jump to a demonstrated human longevity effect has not been made. And rapamycin has decades of human safety data as an approved transplant medication. NMN does not.
The pattern in gerontology has been consistent: a compound extends mouse lifespan, marketing races ahead, human data underperforms. Resveratrol is the paradigm case. NMN is currently earlier in the same cycle. Being honest about that pattern does not mean the compounds are useless — it means the confidence level implied by consumer marketing is not the confidence level the evidence supports.
The cost calculus
The Sinclair-style dose — 1 g NMN, 1 g resveratrol, 500 mg to 1 g TMG daily — costs $80 to $200 per month depending on brand. Over ten years that is $10,000 to $24,000. For that spend, the honest expected return, given the current evidence, is: possibly improved insulin sensitivity in some populations, plausible modest antioxidant effects, and an uncertain contribution to long-term biological aging that has not been demonstrated in humans.
For comparison, the interventions with stronger human longevity evidence — regular exercise (both aerobic and resistance), sleep of 7 to 9 hours, a Mediterranean-pattern diet, not smoking, moderate alcohol at most, and maintaining social relationships — cost close to zero and have decades of epidemiological support with effect sizes that dwarf anything demonstrated for the stack. This is not a rhetorical trick. It is the actual comparison.
If you insist on running the stack
If you have read the caveats and want to run the protocol anyway — reasonable, given the compounds are cheap enough for a personal experiment and the safety profile at moderate doses appears clean — third-party testing is the one non-negotiable spec. NMN in particular has had significant purity problems in the retail market, with several third-party lab investigations finding batches contaminated with nicotinamide or containing less NMN than labeled.
The brands most commonly cited for public third-party testing include Do Not Age, Renue By Science, and ProHealth Longevity. That is not an endorsement — Vyvata has not scored these — but they publish certificates of analysis (COAs) from independent labs on their product pages, which is the minimum bar for buying a compound in this regulatory gray zone. Any brand that does not publish a batch-specific COA should be assumed to be selling something you cannot verify.
Practical points if you run the experiment:
- Take it with fat. Both NMN and resveratrol are more bioavailable with a lipid vehicle. Yogurt, olive oil, or a fatty breakfast.
- Take TMG. If you are dosing NMN at gram-per-day levels, the methylation cost is real. Skip TMG only if you are also dosing NMN low.
- Get bloodwork before and after. A basic panel — fasting glucose, HbA1c, lipid panel, homocysteine — before starting, and again at 12 weeks. If you cannot demonstrate a change on your own labs, the money is buying a hope, not a result.
- Do not double up on NAD+ precursors. NMN and NR both feed the same pathway. Running both is redundant and doubles the methylation burden.
- Stop if you notice sleep disruption or anxiety. Anecdotal reports of these effects at higher doses exist and are consistent with mechanism.
An honest framing
The Sinclair stack sits in an awkward middle ground. The biochemistry is real. The animal work is real. The specific human evidence for lifespan extension is not yet real. The retail category has manufacturing quality problems and unstable regulatory footing. And the compounds are being marketed by many brands as if the evidence supports certainty it does not.
Vyvata's read is that the category is not yet stable enough to source responsibly. When third-party-tested NMN, resveratrol, and TMG products from brands with clean COAs and regulatory footing appear in a way we can grade against our rubric, we will consider them. For now, the honest recommendation is that a reader interested in longevity get the boring, high-evidence basics locked in — sleep, exercise, food quality, blood pressure control, not smoking — before spending four figures a year on a stack whose lifespan claims have not been demonstrated in humans.
Nothing in this article is medical advice. Talk to a physician before adding gram-per-day supplements to your routine, particularly if you take methylation-relevant medications or have a family history of cardiovascular disease. The honest limitations of the evidence are the point of the article; they should be the starting point of the decision.
