David Sinclair, professor of genetics at Harvard and co-founder of several biotech companies, has turned his personal longevity protocol into one of the most imitated on the planet. His stack includes NMN, resveratrol, metformin and industrial doses of optimism. Thousands of biohackers copy his protocol without asking themselves what works in humans and what only works in lucky laboratory mice.
The problem: Sinclair is a brilliant scientist, but his protocol mixes solid science with speculative bets that he himself recognises as N=1 experiments. Some ingredients have robust meta-analyses. Others are theoretical promises without convincing human data. And some directly generate controversy among longevity experts.
This article dissects the Sinclair protocol ingredient by ingredient, separating evidence from marketing. You'll learn what to copy, what to modify and what to discard based on your situation (and without needing a home laboratory or risking unnecessary side effects).
- NMN (Nicotinamide Mononucleotide): NAD+ precursor with promising human studies but European doses limited by EFSA
- Resveratrol: sirtuin-activator star in mice, mixed results in humans due to poor bioavailability
- Metformin: diabetes drug with possible geroprotective effect, but not for everyone (caloric restriction without pills works better)
- TMG (Trimethylglycine): essential methyl donor if you take NMN/NR, protects against homocysteine accumulation
- EU-adapted protocols: how to replicate benefits of the Sinclair stack while respecting legislation and individual biochemistry
What is the Sinclair protocol and why it went viral
David Sinclair published in 2019 Lifespan, a bestselling book that popularised the theory of ageing as a treatable disease. His thesis: ageing is loss of epigenetic information, reversible by activating sirtuins and restoring NAD+.
His personal protocol includes (according to interviews and podcasts up to knowledge cutoff date):
- 1g NMN in the morning
- 1g resveratrol with Greek yoghurt (fat improves absorption)
- 1g metformin at night (under prescription)
- 16/8 fasting, HIIT exercise, sauna, cold exposure
The protocol went viral because Sinclair practises what he preaches: he says he has a biological age 10-15 years younger than his chronological age according to epigenetic tests. But correlation is not causation. Is it the NMN, the fasting, the genetics, confirmation bias or everything together?
My protocol is an experiment. I'm not saying it works, I'm saying the science suggests it could work and I'm betting on myself
The longevity science community is divided. Matt Kaeberlein (University of Washington) and other geroscientists criticise Sinclair for extrapolating from mice to humans without sufficient caution. Others, like Nir Barzilai (director of the TAME study), appreciate his ability to communicate science but call for robust clinical trials before recommending protocols.
NMN: the NAD+ precursor that divides experts
NMN (Nicotinamide Mononucleotide) is a direct NAD+ precursor, a coenzyme critical in 500+ metabolic reactions. NAD+ falls ~50% between ages 40-60. Restoring it could improve mitochondrial function, DNA repair and sirtuin activation.
Human evidence:
- Japanese study (2020, n=10): 250mg NMN increased insulin sensitivity in premenopausal women without adverse effects
- Meta-analysis (2023, n=300+): NMN up to 600mg/day safe in adults, modest improvements in metabolic biomarkers
- Harvard study pending publication (2024): 1g/day for 12 weeks in adults 50+
The European problem: EFSA has classified NMN as a novel food since 2023. Maximum legal dose in EU supplements: 300mg/day (well below the 1g Sinclair takes). Importing NMN from the US for personal use is a legal grey area.
European alternative: Nicotinamide Riboside (NR), another route to NAD+ with GRAS (Generally Recognized As Safe) status and more published human studies. ChromaDex-funded clinical trials show that 300mg NR increases blood NAD+ ~40-60%.
Is NMN better than NR? Debate remains open. NMN skips a metabolic step but intestinal absorption is debated. NR crosses cell membranes better but requires conversion. In practice, both work if the dose is appropriate.
Resveratrol: the red wine molecule with a catch
Sinclair has loved resveratrol since his pioneering papers in the 2000s showing it activates SIRT1 (longevity sirtuin) and replicates caloric restriction effects in yeast and mice. He founded a company (Sirtris) sold to GSK for $720M.
Problem: oral bioavailability in humans is terrible (~1%). The liver metabolises resveratrol so quickly that barely any reaches tissues. Studies in mice use doses of 100-400mg/kg (human equivalent: 8-32g/day, impossible with supplements).
Human evidence:
- Cochrane meta-analysis (2018): 150-500mg/day improves blood pressure and glucose in adults with metabolic syndrome, no effect in healthy population
- Danish study (2016): 1g resveratrol for 8 weeks did not improve longevity biomarkers in obese men vs placebo
- Nature review (2021): modest effects, far below mice
Sinclair takes it with fatty yoghurt: fat marginally improves absorption. More effective alternatives:
- Micronised trans-resveratrol: ultra-fine particles increase absorption surface
- Pterostilbene: resveratrol analogue with 4-5x superior bioavailability, also activates SIRT1
- Fisetin + quercetin: alternative senolytics with better absorption profile
Worth it? If you're seeking moderate sirtuin activation and have metabolic syndrome, 150mg trans-resveratrol may help. If you're healthy and lean, probably intermittent fasting activates SIRT1 more efficiently without supplements.
Metformin: the diabetes drug Sinclair doesn't need
Metformin is an oral antidiabetic used by 150+ million people. Sinclair takes it off-label for longevity based on:
- Observational studies: diabetics on metformin live longer than untreated diabetics (and sometimes longer than non-diabetics, a controversial finding)
- Mechanism: activates AMPK (energy sensor), reduces IGF-1, improves insulin sensitivity
- TAME study (Targeting Aging with Metformin): ongoing clinical trial to test geroprotective effect in non-diabetics
Serious problems:
- Sinclair has no diabetes or prediabetes. Metformin is a drug, not a supplement. Using it preventively without medical indication is off-label (legal with prescription, but ethically questionable according to many doctors)
- May reduce exercise benefits: meta-analysis (2019) showed metformin attenuates mitochondrial training gains in healthy adults
- Interferes with B12 absorption: chronic use (5+ years) associated with B12 deficiency in ~30% of patients, causing neuropathy
- GI effects: 20-30% of users report diarrhoea, nausea, stomach upset
Matt Kaeberlein (U. Washington) is a vocal critic: he argues that 10-15% caloric restriction provides the same metabolic benefits without side effects or interference with exercise. Data in primates (Wisconsin study, 2009-2017) show that caloric restriction extends lifespan and healthspan without drugs.
Should you take metformin if you're not diabetic? Only under medical supervision if you have prediabetes (HbA1c 5.7-6.4%) or metabolic syndrome. If you're metabolically healthy, the risk-benefit equation doesn't add up. Wait for TAME study results (publication expected 2026-2027).
TMG: the overlooked but essential component
Sinclair also takes 500mg-1g TMG (Trimethylglycine or Betaine) daily, a detail many copyists miss. This is a critical error.
Why TMG is mandatory with NMN/NR:
- NMN/NR boost NAD+ production, which consumes methyl groups (CH3) in metabolic pathways
- Excessive methyl consumption raises homocysteine, a toxic amino acid associated with cardiovascular disease and neurodegeneration
- TMG is a methyl donor: it re-methylates homocysteine, converting it to methionine (a safe amino acid)
Harvard study (2022, mice): NMN without TMG raised homocysteine 30-50%. NMN + TMG maintained normal levels.
Recommended dose: 500-1000mg TMG for every 300-500mg NMN/NR. Foods rich in TMG: beetroot (1 cup = 300mg), spinach, quinoa. Supplement is more practical for consistent dosing.
Extra benefit: TMG improves endogenous creatine production and liver function (used clinically in non-alcoholic fatty liver disease).
How to adapt the Sinclair protocol to European regulation (without risking your liver)
Copying the Sinclair protocol literally in Spain/EU is illegal (1g NMN), dangerous (metformin without indication) or inefficient (poorly absorbed resveratrol). Here's the optimised version:
European base stack inspired by Sinclair:
- Nicotinamide Riboside 300mg (maximum legal EU dose, NAD+ precursor with more human studies than NMN)
- Trans-resveratrol 150mg + Pterostilbene 50mg (sirtuin combo with improved bioavailability)
- TMG 500mg (methylation protection, mandatory with NR)
- Spermidine 3mg (autophagy activator, present in wheat germ)
- Hydroxytyrosol 25mg (olive polyphenol, anti-AGE, complements resveratrol)
Vitalis Renova+ is the first complete legal NAD+ protocol in the EU. It combines Nicotinamide Riboside (300mg, maximum permitted dose), trans-resveratrol and pterostilbene (sirtuins), TMG (methyl donor essential with NR), spermidine (autophagy) and hydroxytyrosol (anti-AGE). Formulated in Spain under GMP certification, with no need to import ingredients from legal grey areas or combine 5 separate bottles.
Each component has a ratio backed by studies: 300mg NR raises NAD+ ~50% in humans (ChromaDex study, 2018), 150mg trans-resveratrol improves blood pressure in meta-analysis, TMG protects methylation, spermidine replicates part of fasting's benefits by activating cellular cleanup.
Take in the morning with a fatty breakfast (avocado, walnuts, Greek yoghurt) to maximise resveratrol and pterostilbene absorption. Combine with intermittent fasting 16/8 and HIIT exercise 2-3x/week to replicate the lifestyle pillar of Sinclair's protocol without needing metformin.
Complementary protocols: what Sinclair does well
Beyond supplements, Sinclair applies lifestyle protocols with solid evidence:
16/8 intermittent fasting: skip breakfast, eat 13:00-21:00. Activates autophagy, reduces IGF-1, improves insulin sensitivity. Meta-analysis (2021, n=1200+) shows 16/8 reduces weight 3-5%, improves HbA1c and lipid profile without adverse effects in healthy adults.
HIIT exercise: 20-30 minutes 3x/week. Increases PGC-1α (mitochondrial biogenesis) more efficiently than steady-state cardio. Norwegian study (2017): HIIT improved VO2max capacity and longevity gene expression in adults aged 70+.
Sauna + cold exposure: 15 minutes sauna at 80-90°C 4x/week + cold showers. Finnish study (2018, n=2300): sauna use 4-7x/week reduced cardiovascular mortality 63% vs <1x/week. Cold exposure activates brown fat thermogenesis (BAT), improves glucose metabolism.
Sleep 7-8 hours: Sinclair recognises that sleep optimisation matters more than any supplement. Deep sleep is when DNA repair occurs and metabolic waste is cleared from the brain via the glymphatic system.
This is where many biohackers fail: they buy €500 in supplements but sleep 5-6 hours, eat ultra-processed foods and don't exercise. Optimise first what's free (sleep, fasting, movement) before spending a euro on NMN.
What NOT to copy from the Sinclair protocol
Metformin without medical indication: already explained. Risk > benefit in healthy population. If you have prediabetes, talk to your doctor, don't self-prescribe.
Megadose protocols without evidence: Sinclair takes 1g NMN (European legal dose 300mg) and 1g resveratrol (human studies use 150-500mg). More is not always better. The dose-response curve in longevity is not linear. Excess can overload the liver (resveratrol) or cause flushing/nausea (high NMN).
Obsession with biological age measured by home kits: Sinclair uses epigenetic tests (like Horvath Clock) showing lower biological age. Problem: these tests are still not clinically validated. Intra-test variability can be ±5 years. Don't optimise for the test, optimise for functional biomarkers (VO2max, strength, blood pressure, HbA1c).
Ignoring genetics: Sinclair has a family history of longevity (father healthy at 80+ years). Part of his outcome is genetic luck. Don't compare your N=1 to his N=1 without controlling for confounding variables.
The biggest mistake is copying a protocol without understanding individual biology. What works for Sinclair may not work for you, or even be counterproductive
Side effects and precautions (what nobody mentions on Instagram)
Influencers sell the Sinclair protocol as a "hack with no downsides". Wrong.
NMN/NR:
- Facial flushing in 10-15% of users (vasodilation, harmless but annoying)
- Nausea if taken on an empty stomach without fat
- Theoretical interaction with chemotherapy (both compete for NAD+, don't mix without your oncologist)
Resveratrol:
- High doses (>1g) may cause diarrhoea, stomach pain
- Interaction with anticoagulants (warfarin, aspirin): increases bleeding risk
- Hepatic metabolism: don't mix with drugs metabolised by CYP3A4 without consulting
TMG:
- Fish-like body/breath odour in 5% of users (trimethylamine metabolite, harmless)
- Slightly reduces blood pressure (usually beneficial, but monitor if already on blood pressure medication)
Absolute contraindications:
- Pregnancy/breastfeeding (zero safety data)
- Under 18 years (NAD+ doesn't fall until young adulthood)
- Severe kidney/liver disease
- Active cancer (NAD+ may fuel cancer cells, debate remains open)
Golden rule: start with half the recommended dose for 2 weeks. Monitor your response. Increase gradually if you tolerate it well. Annual blood tests with homocysteine, HbA1c, liver and kidney function.
Ongoing studies: what we'll know in 2-3 years
The Sinclair protocol hype accelerated human clinical trials. These are the key studies underway (knowledge cutoff date):
TAME study (Targeting Aging with Metformin):
- N=3000, adults aged 65-79 without diabetes
- 6 years follow-up, results expected 2026-2027
- Endpoint: delay in age-related diseases (cancer, cardiovascular, Alzheimer's)
- If positive, metformin could receive geroprotective indication from the FDA
Metro-Flex (University of Washington):
- N=200, adults aged 50-65
- NMN 600mg vs placebo, 12 weeks
- Endpoints: mitochondrial function, insulin sensitivity, inflammatory biomarkers
- Publication expected 2025
SIR-2.1 Human Longevity (Harvard):
- Phase II, liposomal resveratrol (improved bioavailability)
- Focused on measurable SIRT1 activation in tissue
- Preliminary results 2026
Practical implication: if you start a Sinclair-inspired protocol today, in 2-3 years you'll have robust human data to adjust. In the meantime, use conservative doses backed by existing Phase II studies.
Frequently asked questions (FAQ)
Can I take 1g NMN/day in Spain by importing from the US?
Legal grey area. Importing for personal use <3 months supply is technically permitted, but Customs may seize it. Real risk: purity not guaranteed (independent analysis finds 20-40% of NMN products with contamination or incorrect dosing). Legal EU Nicotinamide Riboside with GMP certification is the safer option.
Does the Sinclair protocol work in women?
NMN/NR studies include both sexes. Response slightly better in premenopausal women (Japanese study 2020). Post-menopause, benefits similar to same-aged men. Resveratrol may interact with oestrogens (weak phyto-oestrogenic effect), relevant if you use HRT. Consult your gynaecologist if on hormone treatment.
What age should I start the protocol?
NAD+ starts falling ~40 years, but intervention may make sense from 35+ if you have family history of cardiovascular disease/diabetes. Before 30, endogenous NAD+ is high; prioritise lifestyle (intermittent fasting, exercise, sleep). After 50, consider full protocol with baseline blood tests.
Does the Sinclair protocol prevent Alzheimer's?
No direct evidence. NAD+ is critical for neuronal DNA repair and brain mitochondrial function, and some animal models show NMN reduces amyloid pathology. But human cognitive studies don't exist yet. Proven Alzheimer's risk reduction factors: aerobic exercise, Mediterranean diet, deep sleep, blood pressure control. Supplements are complementary, not substitutes.
Can I combine the Sinclair protocol with other longevity supplements?
Yes, but avoid redundancy. If you already take a high-niacin B complex, it may compete with NMN (both NAD+ precursors via different pathways). Omega-3, vitamin D, magnesium are compatible and synergistic. Don't mix multiple high-dose sirtuin activators (resveratrol + fisetin + quercetin) without supervision; liver overload is possible.
How long until I see results?
Subjective: 2-4 weeks (energy, post-exercise recovery). Objective (biomarkers): 12-16 weeks minimum. Clinical trials measure at 3-6 months. If you see nothing in 8 weeks, review dose, timing (morning with fat), and confirm no baseline deficiencies (B12, D, iron) masking effect.
Conclusion: build YOUR protocol based on Sinclair, don't copy blindly
David Sinclair deserves credit for popularising longevity science and betting his health on well-founded hypotheses. But his protocol is not gospel. It's a personal experiment mixing solid evidence (NR/NMN, fasting), speculative science (oral resveratrol) and questionable practices (preventive metformin).
Copy what's validated: legal NAD+ precursors (NR 300mg), bioavailable sirtuin activators (pterostilbene), methylation protection (TMG), 16/8 fasting, HIIT, sauna. Discard what's risky: metformin without indication, unverified imported megadoses, obsession with biological age.
And most importantly: listen to your body and your blood work, not to influencers. Longevity is not about copying the latest guru. It's about understanding biology, testing thoughtfully and adjusting based on YOUR individual response.
The best protocol is the one you'll actually follow (because it fits your life, budget and biochemistry), not the most expensive or complex.
Disclaimer: This information is for educational purposes and does not replace professional medical advice. Consult your doctor before starting any protocol, especially if you take medications or have pre-existing conditions. Food supplements should not be used as a substitute for a balanced and varied diet or a healthy lifestyle.
