Rapamycin + Metformin: The Anti-Aging Stack I’m Running at 53

I get asked about my longevity stack roughly once a week. The two compounds that come up first are rapamycin and metformin, because both have meaningful human and animal data on lifespan extension, both are cheap, both are widely available, and both are off-label for the use I’m putting them to.

This is what I’m actually running. Not what the longevity Twitter pundits say to run. Not what Peter Attia says to run. What I, Tony Huge, 53 years old, am putting in my body in Pattaya, with bloodwork to back it up.

Why these two together

The simplest argument for stacking rapamycin and metformin is that they hit two of the most important aging-related metabolic pathways from opposite directions:

• Rapamycin inhibits mTOR — the master growth and protein-synthesis signal. Chronic mTOR activation is one of the most reproducible accelerators of aging across model organisms.
• Metformin activates AMPK — the cellular energy-stress sensor that turns on autophagy, mitochondrial biogenesis, and the cleanup machinery that mTOR turns off.

Suppress mTOR. Activate AMPK. The combined effect, on paper, is shifting cellular metabolism toward repair and away from constant growth-mode signaling. The TAME trial (Targeting Aging with Metformin) and the ITP (Interventions Testing Program) rapamycin data both support the underlying idea.

My actual rapamycin protocol

• Dose: 6 mg once weekly, oral.
• Timing: Sunday morning, fasted, with a small fat meal 30 minutes later to improve absorption.
• Training week scheduling: I take the rapamycin dose on my lowest-training day. Rapamycin blunts mTOR for 48–72 hours, which is exactly the signal you need for muscle protein synthesis. Take it on a heavy training day and you’re working against yourself.
• Cycling: 6 weeks on, 1 week off, repeated indefinitely. The week off is to let immune function fully normalize.

The “once weekly” pulse-dosing approach is the consensus among physicians actually prescribing rapamycin for longevity — Alan Green, Peter Attia, Matt Kaeberlein, and most of the academic mTOR researchers. Daily dosing is the transplant-immunosuppression protocol and is not what we’re doing. The pulse approach gets you the mTOR inhibition you want with much less of the immune suppression you don’t.

My actual metformin protocol

• Dose: 500 mg extended-release, twice daily, with meals.
• Total daily dose: 1000 mg/day. This is the low end of therapeutic dosing for type 2 diabetes and the dose most longevity-focused physicians prescribe for non-diabetics.
• Skip days: I skip metformin on heavy training days. AMPK activation can blunt the hypertrophy signal from training. The TAME-style longevity argument doesn’t require you to take metformin every single day forever.

Note: I’m not diabetic. My fasting glucose is in the high 80s/low 90s, my HbA1c is 5.2–5.4, my fasting insulin is in the 4s. I’m using metformin off-label for its longevity-associated mechanisms, not for glycemic control.

The bloodwork I track

Quarterly:

• CBC (rapamycin can drop white cells if dose-titrated wrong — at 6 mg weekly mine stays normal)
• Comprehensive metabolic panel (kidney/liver function)
• Fasting glucose, fasting insulin, HbA1c (track AMPK activation effects)
• Fasting lipid panel (rapamycin can raise lipids in some users — mine has not been affected)
• HsCRP and IL-6 (inflammation markers — both rapamycin and metformin lower these)
• Vitamin B12 (metformin reduces B12 absorption over time — I supplement methyl-B12 sublingually)
• Lactate (very rarely an issue at low-dose metformin, but worth occasional check)

Annually:

• Coronary artery calcium scan (cardiovascular risk surveillance)
• Full body MRI (cancer surveillance — relevant because mTOR inhibition could in theory mask early tumor metabolism)
• DEXA (body composition + bone density)

What I’ve actually noticed

Honest answer: the subjective effects of this stack are small. That’s expected. Longevity interventions don’t make you feel like you took a stimulant; they’re slow, cumulative, mechanism-based bets that the underlying biology shifts in a favorable direction over years.

What I have noticed:

• Lower fasting glucose drift. On metformin I run 4–6 mg/dL lower fasting glucose than off it. Small. Consistent.
• Lower hsCRP. My inflammation marker dropped from ~1.4 to ~0.8 over the first 6 months of running this stack. Diet was constant. The most likely driver is the combination of mTOR and AMPK effects on chronic low-grade inflammation.
• Sleep quality: No clear change attributable to either drug.
• Training: When I skipped the dose-day rule once and took rapamycin on a heavy leg day, my next two sessions felt 10–15% weaker. The mTOR-blunting on muscle protein synthesis is real if you mistime it.
• GI side effects: Metformin XR is generally well-tolerated. Two days of mild GI adjustment at the start, then nothing.
• Mouth sores: The classic rapamycin side effect. I’ve had a mild one twice in ~18 months. Both resolved in a few days.

Risks I take seriously

Rapamycin is an immunosuppressant. At 6 mg weekly pulse-dosed, the immune impact is much smaller than daily transplant dosing, but it’s not zero. I do not take rapamycin if I’m fighting an infection, if I’ve been around sick people, or in the days around major travel where I’m going to be exposed to new pathogen pools.

Drug interactions. Rapamycin is CYP3A4-metabolized. Grapefruit, ketoconazole, certain antibiotics will spike rapamycin blood levels. Don’t stack carelessly.

Lactic acidosis is the metformin scare story. At 1000 mg/day in a person with normal kidney function it is vanishingly rare. If your eGFR drops below 45, you stop. If you’re going to be drinking heavily, you skip the dose. If you’re going in for contrast imaging, you skip for 48 hours.

Muscle. Both drugs blunt some component of the muscle-building signal. If you’re a competitive bodybuilder or in an aggressive recomp phase, the longevity stack will modestly cost you progress. Be honest about your priorities. I am 53 and not trying to add 10 lb of lean mass; I am trying to hold what I have while reducing the rate at which my biology accumulates damage.

Who should consider this stack

• People over 40 who are otherwise metabolically healthy and willing to do quarterly bloodwork.
• People with family history of cardiovascular or neurodegenerative disease.
• People whose primary health goal at this stage of life is healthspan extension, not aesthetic body composition.

Who shouldn’t:

• People under 35 (your endogenous mTOR/AMPK signaling is fine; no upside).
• People actively trying to build muscle aggressively.
• People without access to monitoring bloodwork and a willing physician.
• People with active infection, immune deficiency, or recent surgery.

Sourcing

Both are cheap, both are widely available, both are prescription drugs that compounding pharmacies and telehealth longevity clinics will write for off-label use. The Healthspan / AgelessRx / Healthy Longevity Clinic models all exist precisely because there’s enough off-label demand to support them. I get mine through a Bangkok pharmacy network.

What this fits into

The rapamycin/metformin stack is part of a larger longevity protocol that also includes low-dose SGLT2 inhibitor (dapagliflozin), a managed TRT protocol, my weekly CJC/Ipamorelin GH peptide cycle, methylene blue for mitochondrial support, and the basics — 7–8 hours of sleep, four training sessions a week, sub-12% body fat, and a real social life. The drugs are not a substitute for the basics. They are the icing on the cake when the basics are handled.

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