Rapamycin dosage for longevity: where the numbers actually come from

Why there is no established rapamycin dosage for longevity

A dose is normally set by finding the amount that produces a measurable benefit at acceptable risk. For longevity there is no measurable benefit to titrate against. There is no biomarker anyone agrees tracks the outcome, no clinical endpoint short of decades, and therefore nothing to optimize toward. What exists instead is a tolerability ceiling, and a great deal of convention.

That is not a technicality. Every dose figure you will read is either an animal number, a transplant number, or a description of what people are already doing. None of them is an answer to the question being asked.

What the animal data actually specify

Strong human evidence The 2009 result that started this used food containing 14 parts per million, roughly 2.24 mg per kilogram per day, given from 600 days of age.^[1] Later work tested higher concentrations, and a review of the dose and timing literature found that mid-life initiation extends mouse lifespan by roughly 9 to 14 percent depending on the regimen.^{[2] [3]}

Two things follow. First, the animal evidence is for continuous exposure, not weekly pulses, which is a substantial difference from what humans actually do. Second, converting milligrams per kilogram in a mouse into milligrams in a person requires metabolic scaling assumptions that have never been validated for this drug. Reviews of animal regimens note intermittent schedules as the ones that avoided adverse metabolic effects, which is where the human intermittent logic originates.^[4]

Where 6 mg weekly came from

A systematic review of rapamycin and rapalog use in humans found the most common off-label regimens were 6 mg once per week and 6 mg once every 14 days.^[5] A 2025 GeroScience analysis of real-world cohorts reached the same conclusion independently: 6 mg per week was by far the most commonly administered longevity dose.^[6]

Note what those two papers are describing. They are documenting behavior, not validating it. The figure spread through clinician networks, podcasts and forums, and its main qualification is that a lot of people use it. That is how a convention forms, and it is not the same as evidence.

There's nothing saying that 6 mg is the best dose.

The finding that undermines milligram thinking

The same 2025 cohort work measured blood levels rather than just doses, and found wide variation between individuals taking identical amounts.^[7] Absorption, body composition, CYP3A4 activity and whether the tablet was taken with food all move the number.

So two people on 6 mg weekly may not be running the same experiment at all. The transplant world solved this decades ago by dosing to a measured blood concentration rather than to a milligram figure. Longevity use cannot copy that solution, because no target concentration for the intended effect has ever been defined.

What the human trials used

Early / mixed evidence The PEARL trial compared 5 mg and 10 mg weekly against placebo over 48 weeks in healthy older adults, reporting tolerability alongside changes in lean tissue and self-reported pain.^[8] It was a safety and feasibility study. It did not test a dose range against an efficacy endpoint, because there is no agreed efficacy endpoint to test against.

A recent review of off-label use in healthy adults reached the conclusion that the clinical picture remains insufficient to guide practice.^[9] That assessment applies to the dose question with particular force.

Why weekly rather than daily

The pharmacological argument is specific. Brief exposure inhibits mTORC1. Sustained exposure also reaches mTORC2, and mTORC2 inhibition is where much of the insulin resistance and metabolic disturbance seen in transplant patients is thought to originate. A weekly dose with six days of clearance is an attempt to separate the two.

The argument is plausible and not proven in humans. It is also the reason the transplant side effect list may not transfer, which we go through in detail in our page on what changes at different doses.

For the most part, I think once a week seems to work out best.

What responsible dosing looks like in practice

Clinicians who prescribe it off-label generally start low, extend the interval, and adjust on tolerability. Mouth ulcers are the practical signal that exposure has risen, and the response is a smaller dose or a longer gap. Monitoring covers the effects that produce no symptoms: lipids, blood counts, fasting glucose or HbA1c, liver and kidney function.

Grapefruit is avoided outright rather than adjusted for, because CYP3A4 inhibition raises the effective exposure by an unpredictable amount. The same applies to several common medicines, which is why a prescriber needs the full list before any figure is chosen. Access and prescribing routes are covered in our page on cost and access.

How to read any dose figure you see

Ask which question it answers. If it comes from transplant medicine, it targets a blood concentration for immunosuppression. If it comes from oncology, it targets the maximum the patient can tolerate. If it comes from a mouse, it is continuous exposure in an animal with a much faster metabolism. If it comes from a longevity protocol, it describes what people do, and nothing more.

None of those is a rapamycin dosage for longevity in the sense the question implies, because that number does not exist yet. Anyone quoting one with confidence is quoting a convention. Our main evidence guide sets out what a trial would have to show before a real number could be written down.

Frequently asked questions

What is the rapamycin dosage for longevity?

There is no established one. The dose that appears most often in surveys of people already taking it is 6 mg once a week, and that number reflects convergent practice rather than any trial that compared doses. No regulator has approved a longevity dose and no trial has identified an optimal one.

How much rapamycin do people actually take?

A systematic review of off-label use found the most common regimens were 6 mg once a week and 6 mg every 14 days, with a minority reporting much higher amounts. A 2025 real-world cohort analysis reached the same conclusion: 6 mg weekly dominates.

Why is rapamycin taken weekly instead of daily?

Because the two mTOR complexes respond differently to exposure length. Brief inhibition hits mTORC1, the growth and nutrient sensor. Sustained inhibition also reaches mTORC2, which is where much of the insulin resistance and metabolic disturbance of transplant dosing is thought to come from. Weekly dosing is an attempt to get one without the other.

Does blood level testing help with dosing?

It reveals how variable the picture is. A 2025 cohort study found that identical weekly doses produced widely different blood concentrations between individuals, which means milligrams are a poor proxy for exposure. What nobody knows is which blood level, if any, corresponds to a longevity benefit.

What dose was used in the PEARL trial?

Five milligrams and 10 mg weekly, compared against placebo across 48 weeks in healthy older adults. It reported tolerability and some changes in lean tissue and self-reported pain. It was not designed to find an optimal dose and did not compare a range of them.

What dose extends lifespan in mice?

In the landmark 2009 result, 14 parts per million in food from 600 days of age, roughly 2.24 mg per kilogram per day. Later work tested higher concentrations. Translating any of these into a human milligram figure requires assumptions about metabolic scaling that nobody has validated.

Is more rapamycin better?

There is no evidence for that and reason to think the opposite. Higher and more continuous exposure is exactly what produces the transplant side effect profile, and the animal dose-response is not simply linear. The people taking 20 mg or more are running an experiment on themselves with no supporting data.

How do clinicians decide where to start?

In practice, low and slow: a small starting amount, a long interval, and adjustment based on tolerability rather than any measured endpoint. That is a reasonable way to manage side effects. It is not a way to find an effective dose, because the effective dose has never been defined.

Should the dose be based on body weight?

The animal data are expressed per kilogram, and some clinicians scale accordingly. Human off-label practice mostly does not, which is one of several inconsistencies between the animal evidence people cite and the human protocols they follow.

Does grapefruit change the dose?

Effectively yes, and unpredictably. Grapefruit inhibits CYP3A4, the enzyme that clears the drug, so it raises blood concentration by an amount nobody can estimate in advance. This is why it is avoided rather than accounted for.

How long should someone stay on it?

Unknown. Every off-label protocol in circulation is open-ended, and no trial has run long enough to say whether a benefit accumulates, plateaus or reverses. The animal work suggests that starting in mid-life is sufficient, which at least argues against the idea that earlier is obviously better.

Is there a standard cycling protocol?

No. Some people take breaks of a few weeks or months, usually reasoning about immune function or wound healing around surgery or illness. None of these schedules has been tested against continuous weekly dosing.

What monitoring goes with any dose?

A lipid panel, complete blood count, fasting glucose or HbA1c, and liver and kidney function, taken before starting and repeated periodically. These catch the effects that produce no symptoms, which are the ones self-directed use misses entirely.

Why do the published figures disagree with each other?

Because they answer different questions. Transplant doses target a blood concentration. Oncology doses target the maximum tolerated ceiling. Longevity doses target nothing measurable, so they converge on convention instead, which is how 6 mg weekly became a standard without ever being tested as one.