Rapamycin (Sirolimus): Half-Life, Label and Studies
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Rapamycin: half-life, strengths and approval status

Tablet strengths · Approval status · Half-life ~62 hours (about 2.6 days)

Short answer: Rapamycin has a half-life of about 62 hours (about 2.6 days). Levels peak about 1 to 3.5 hours after a dose. People vary, so treat these as estimates.

What is rapamycin?

Rapamycin, also called sirolimus, is an mTOR inhibitor that suppresses the immune system. The FDA label approves it to prevent kidney transplant rejection and to treat lymphangioleiomyomatosis (LAM), a rare lung disease. Use for aging or longevity is off-label.

Also known as: sirolimus, Rapamune.

Tablet strengths

Generic sirolimus tablets come in 0.5 mg, 1 mg and 2 mg strengths, and an oral solution is also sold. The label says not to crush, chew or split the tablets.

Approval status and how it is used

The FDA sirolimus label approves it to prevent organ rejection in kidney transplant patients aged 13 and older, and to treat LAM. It is taken once a day by mouth, the same way each day either with or without food. For LAM the label starts at 2 mg a day and adjusts the dose by blood levels (a trough of 5 to 15 ng/mL). For kidney transplants it starts with a loading dose (6 mg on day 1, then 2 mg a day in the main regimen with cyclosporine). Grapefruit juice must not be taken with it, and live vaccines should be avoided.

The label carries a boxed warning: immune suppression raises the risk of infections and of lymphoma and other cancers, and use in liver or lung transplants is not recommended because of deaths, graft loss and airway healing problems in studies.

Use for aging is off-label and rests mostly on animal data. In a 2009 study in genetically mixed mice (Harrison, Nature), rapamycin started late in life raised lifespan, measured at 90% mortality, by 14% in females and 9% in males. In older adults, a 2014 trial of everolimus, a related mTOR inhibitor, found about a 20% better response to the flu vaccine (Mannick). The 48-week PEARL trial (2025) gave healthy adults placebo or 5 mg or 10 mg compounded rapamycin once a week: side effects were similar across groups, visceral fat (the main outcome) did not change, and lean mass and pain improved in women on 10 mg. Its authors work for the company that ran it. These are trial protocols, not personalized advice; confirm any dosing with your prescriber.

Rapamycin half-life and time to peak

  • Half-lifeabout 62 hours (about 2.6 days)
  • Time to peak (Tmax)about 1 to 3.5 hours

The FDA sirolimus label gives a mean terminal half-life of about 62 hours after repeated dosing in stable kidney transplant patients. Peak levels came about 1 hour after the oral solution in healthy people and about 2 hours in transplant patients; at steady state in transplant patients the mean time to peak was 2.1 hours for the solution and 3.5 hours for tablets. A high-fat meal raised total exposure by 23% to 35%.

Numbers shown are taken from the source above. Half-life varies from person to person.

How to track rapamycin in Dose Track

  1. Add rapamycin as a custom compound. Start typing its name and Dose Track fills in the details from its research library for you to check, and it sits next to everything else you take.
  2. Log each tablet when you take it, so your history shows exactly what you took and when.
  3. Set reminders on your own schedule, whether that is daily, weekly or every few days.
  4. Your log is stored on your phone and no account is needed. Data only leaves it for features you choose, like AI answers and lab reading.

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Frequently asked questions

What is the half-life of rapamycin?+
The FDA sirolimus label gives a mean terminal half-life of about 62 hours after repeated dosing in stable kidney transplant patients. Peak levels came about 1 hour after the oral solution in healthy people and about 2 hours in transplant patients; at steady state in transplant patients the mean time to peak was 2.1 hours for the solution and 3.5 hours for tablets. A high-fat meal raised total exposure by 23% to 35%.
Is rapamycin approved for longevity?+
No. The FDA sirolimus label approves it only to prevent kidney transplant rejection and to treat LAM. Use for aging is off-label. The evidence is mostly in animals, plus small human trials such as PEARL, which used 5 mg or 10 mg once a week for 48 weeks.
Why is rapamycin sometimes taken once a week?+
The label doses sirolimus once a day for transplants and LAM. Weekly schedules come from off-label longevity studies such as the PEARL trial. The label half-life is about 62 hours, so each dose stays in the body for days.
What should not be taken with rapamycin?+
The FDA label says grapefruit juice must not be taken with sirolimus, because it raises sirolimus levels. Strong drugs that block or speed up the CYP3A4 enzyme also change its levels, and live vaccines should be avoided.
Can I track rapamycin in Dose Track?+
Yes. Rapamycin is in Dose Track's research library, so when you add it as a custom compound its details are filled in for you to check. You can then log each tablet next to your other compounds, set reminders on your own schedule, and see your history next to your lab results. Your log is stored on your phone and no account is needed. Data only leaves it for features you choose, like AI answers and lab reading.

Sources

  1. Sirolimus tablets (Glenmark) prescribing information, boxed warning and sections 1, 2, 3, 5, 7 and 12.3. DailyMed, January 2026.
  2. Harrison DE, et al. Rapamycin fed late in life extends lifespan in genetically heterogeneous mice. Nature. 2009;460(7253):392-395.
  3. Mannick JB, et al. mTOR inhibition improves immune function in the elderly. Sci Transl Med. 2014;6(268):268ra179.
  4. Moel M, et al. Influence of rapamycin on safety and healthspan metrics after one year: PEARL trial results. Aging (Albany NY). 2025;17(4):908-936.

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