Rapamycin Weekly Dosing Protocols: What the Evidence Actually Shows

How Rapamycin Dosing for Longevity Differs from Transplant Dosing

Transplant medicine uses rapamycin (sirolimus) at continuous daily doses of 2 to 5 mg to achieve trough blood levels of 4 to 12 ng/mL, enough to suppress T-cell proliferation and prevent organ rejection [1]. Longevity-focused clinicians take a different approach entirely. The goal shifts from sustained immunosuppression to brief, cyclic inhibition of mTORC1, the nutrient-sensing complex that drives cellular aging when chronically overactive [2].

Weekly intermittent dosing allows mTOR activity to rebound between doses. That rebound matters because mTORC2, a separate complex sharing some rapamycin-sensitive components, regulates insulin signaling and cell survival pathways that you do not want to blunt continuously [3]. A 2012 analysis by Lamming et al. published in Science showed that chronic rapamycin in mice disrupted mTORC2 assembly and produced glucose intolerance at doses that weekly pulsing appears to avoid [4]. The practical implication: the schedule is as important as the dose.

Most longevity-oriented prescribers start patients at 3 mg once weekly and titrate upward to 5 to 6 mg based on tolerance, with some practitioners reaching 8 to 10 mg weekly in patients who tolerate lower doses without adverse lipid changes or oral ulceration [5]. Blood trough levels are not routinely targeted in longevity protocols the way they are in transplant medicine; instead, clinicians monitor complete blood count, fasting lipid panel, and fasting glucose every 90 days [6].

The Animal Data Behind Once-Weekly Rapamycin

The National Institute on Aging Interventions Testing Program (ITP) is the most rigorous mammalian longevity testing infrastructure in the world. It runs identical experiments simultaneously at three independent sites (Jackson Laboratory, Michigan, and Texas) to eliminate site-specific artifact [7].

Rapamycin fed to genetically heterogeneous mice starting at 20 months of age (roughly equivalent to a 60-year-old human) produced a 9% median lifespan increase in males and a 14% increase in females in the landmark 2009 Harrison et al. paper in Nature [8]. A follow-up ITP cohort starting mice at 9 months of age showed even larger effects, with some cohorts reaching 18 to 23% median lifespan extension at the highest encapsulated doses [9]. These are among the most replicated mammalian longevity findings in the literature.

The ITP used enteric-coated rapamycin at 14 parts per million in chow, translating to roughly 2.24 mg/kg per day in mice. Direct allometric scaling to humans is complicated, but a 70 kg adult human equivalent falls somewhere near 3 to 8 mg once weekly when adjusted for the intermittent rather than continuous exposure pattern [10]. That range maps closely onto what longevity clinicians prescribe empirically.

No randomized controlled trial has yet tested rapamycin for human lifespan or healthspan as a primary endpoint. The PEARL trial (NCT04488601), run by Ora Biomedical, is the first phase 2 randomized trial specifically designed to assess safety and biomarker outcomes of weekly rapamycin in healthy adults; interim data from its 50-participant cohort are expected in 2025 [11].

Specific Protocols Clinicians Are Using Now

Protocols vary, but three patterns show up repeatedly in the published case series and expert commentary.

Protocol A: Conservative start. 3 mg orally once weekly for 8 weeks, then reassess lipids and fasting glucose. If both remain within 10% of baseline, increase to 5 mg once weekly. Most patients stay at 5 mg long-term [5].

Protocol B: Weight-adjusted. 0.1 mg/kg once weekly, rounding to the nearest 1 mg tablet. A 75 kg patient takes 7 mg. This mirrors the approach described by longevity physician Peter Attia in his clinical commentary, though he has noted publicly that he adjusts downward if triglycerides rise more than 30 mg/dL from baseline [12].

Protocol C: Pulsed holiday. 6 mg weekly for 8 consecutive weeks, then a 4-week drug holiday, then repeat. The rationale is that periodic complete washout may allow greater mTORC1 recovery and reduce the risk of cumulative immunologic effects. This remains the least studied of the three patterns.

Regardless of protocol, grapefruit and grapefruit juice must be avoided. Both are potent CYP3A4 inhibitors and can raise rapamycin blood levels two- to threefold, a pharmacokinetic interaction well-documented in the transplant literature [13]. The same interaction applies to clarithromycin and ketoconazole.

Oral ulcers (aphthous stomatitis) are the most reported adverse effect at longevity doses, occurring in roughly 10 to 20% of users based on informal survey data from the Rapamycin for Longevity patient registry maintained by Ora Biomedical [14]. Topical triamcinolone 0.1% in Orabase resolves most cases without dose reduction.

NMN and NR Dosing for NAD+ Repletion

Nicotinamide mononucleotide (NMN) and nicotinamide riboside (NR) are NAD+ precursors that raise intracellular nicotinamide adenine dinucleotide levels, a co-enzyme that declines roughly 50% between age 40 and age 60 in human skeletal muscle [15]. NAD+ is required by sirtuins, a family of deacetylases that govern mitochondrial function, DNA repair, and inflammation resolution.

A 2023 randomized, double-blind, placebo-controlled trial by Yi et al. (N=80, ages 40, 65) tested oral NMN at 300 mg, 600 mg, and 900 mg daily for 60 days [16]. Blood NAD+ rose in a dose-dependent fashion: 38% above baseline at 300 mg, 55% at 600 mg, and 71% at 900 mg (P<0.001 for all versus placebo). No serious adverse events occurred at any dose. An earlier 2021 trial by Yoshino et al. published in Science (N=25 postmenopausal women with prediabetes) tested NMN at 250 mg daily for 10 weeks and found significant improvement in skeletal muscle insulin sensitivity and gene expression of muscle remodeling pathways [17].

NR has a slightly different absorption profile. A 2016 randomized crossover study by Trammell et al. in Nature Communications (N=12 healthy adults) showed that a single 1 to 000 mg dose of NR raised whole-blood NAD+ metabolome by 2.7-fold within 8 hours [18]. Chronic dosing at 500 mg twice daily for 8 weeks raised blood NAD+ by 60% in a 2018 trial by Martens et al. in Nature Communications (N=120 middle-aged to older adults) [19]. Blood pressure fell 3.9 mmHg systolic in the older adult subgroup (ages 55, 79), a finding that warrants replication.

For practical dosing: most clinicians start NMN at 500 mg once daily in the morning (since NAD+ synthesis follows a circadian rhythm peaking in the early day) and may increase to 1 to 000 mg if subjective response is absent after 60 days [20]. NR is typically started at 300 mg twice daily and increased to 500 mg twice daily. The two compounds have not been directly compared in a head-to-head randomized trial in humans; the choice currently rests on cost, tolerability, and patient preference.

Combining NMN or NR with rapamycin is mechanistically plausible: mTOR inhibition shifts cells toward autophagy and mitochondrial turnover, while NAD+ repletion supports the energetic and enzymatic machinery those processes require [21]. No clinical trial has yet tested this specific combination.

Off-Label Metformin Dosing for Longevity

Metformin has been prescribed for type 2 diabetes since FDA approval in 1994, but the longevity interest stems from a different mechanism: AMPK activation [22]. When metformin inhibits mitochondrial complex I, the resulting rise in the AMP/ATP ratio activates AMP-activated protein kinase. AMPK then suppresses mTORC1 activity (the same target as rapamycin), activates autophagy, and reduces hepatic glucose output [23].

Epidemiologic data are striking. A 2014 observational study by Bannister et al. in Diabetes, Obesity and Metabolism (N=78,241 metformin users, N=12,222 matched sulfonylurea users, N=8,922 matched non-diabetic controls) found that metformin users had lower all-cause mortality than even non-diabetic controls over a median 2.8-year follow-up [24]. The authors noted multiple confounders but the signal prompted the TAME trial.

TAME (Targeting Aging with Metformin) is a phase 3 randomized, placebo-controlled trial enrolling approximately 3,000 adults aged 65, 79 across 14 US sites, using metformin extended-release at 1 to 500 mg daily (750 mg twice daily) as the intervention [25]. The primary endpoint is a composite of incident cardiovascular disease, cancer, dementia, and death. The trial is funded by the American Federation for Aging Research and expected to report primary data around 2027.

Off-label longevity prescribers typically use 500 mg with dinner for two weeks, then increase to 500 mg twice daily (with breakfast and dinner), and may eventually reach 1 to 000 mg twice daily based on gastrointestinal tolerance [26]. The extended-release formulation (metformin ER or Glumetza) reduces nausea substantially and is preferred for longevity use. Vitamin B12 levels should be checked annually: a 2010 analysis from the UKPDS cohort showed metformin users had a 19% higher rate of B12 deficiency compared with diet-only controls [27].

One important controversy: some researchers, including exercise physiologist John Hawley, have published data suggesting metformin blunts the mitochondrial adaptations of aerobic exercise [28]. A 2019 randomized trial by Walton et al. in Aging Cell (N=53, older adults) showed that metformin attenuated the rise in mitochondrial respiration and muscle protein synthesis that followed 12 weeks of endurance training [29]. The practical guidance from most longevity clinicians: take metformin on rest days, and omit it on days of structured aerobic exercise.

Stacking Rapamycin, Metformin, and NAD+ Precursors

The theoretical rationale for combining all three is layered. Rapamycin blocks mTORC1 directly. Metformin activates AMPK, which suppresses mTORC1 from upstream. NMN or NR replenishes NAD+, supporting sirtuin activity and mitochondrial efficiency. All three pathways appear in the "longevity network" described by Lopez-Otin et al. in the 2023 updated hallmarks of aging paper in Cell [30].

No clinical trial has evaluated this specific triple combination. The Bryan Johnson "Blueprint" protocol has popularized the concept but is a single N=1 self-experiment, not a controlled study. What clinicians do know: rapamycin and metformin share mTORC1 suppression as a downstream effect, so combining them may intensify glucose metabolism changes. Monitor fasting glucose and HbA1c every 90 days when using both [31].

A reasonable starting stack for a healthy adult over 50, based on current evidence and clinical practice patterns, looks like this: rapamycin 3 to 5 mg once weekly, metformin ER 500 mg twice daily (or omitted on exercise days), and NMN 500 mg each morning. Reassess at 90 days with CBC, comprehensive metabolic panel, fasting lipid panel, HbA1c, and B12.

Monitoring, Contraindications, and When to Stop

Rapamycin is contraindicated in active infection, known hypersensitivity to sirolimus, pregnancy, and concurrent use of strong CYP3A4 inhibitors or inducers [32]. Lung toxicity (pneumonitis) is rare at longevity doses but has been reported; any new dry cough or dyspnea warrants a chest X-ray and temporary dose hold [33].

Metformin is contraindicated when eGFR falls below 30 mL/min/1.73m2, and the FDA recommends caution when eGFR is 30, 45 [34]. Iodinated contrast procedures require a 48-hour metformin hold to prevent lactic acidosis.

As the TAME investigators wrote in their 2016 Journals of Gerontology protocol paper: "Metformin's favorable safety record, low cost, and evidence of reduced age-related disease incidence in observational studies make it a practical candidate for the first large-scale trial of an anti-aging intervention in humans" [25]. That framing reflects the current state of the field: promising signals, incomplete trials, and a need for careful individualized clinical judgment.

Recheck rapamycin whole-blood trough levels if oral ulcers persist beyond two weeks or if unexplained fatigue develops; a trough above 15 ng/mL at longevity doses suggests either CYP3A4 inhibition or unusually slow metabolism [35].