Peptide & Experimental

Rapamycin (Sirolimus)

mTORC1 inhibitor · sirolimus, Rapamune

Rapamycin, approved as sirolimus in transplant medicine, inhibits the growth switch mTORC1 and extends lifespan in model organisms. In humans, the largest longevity trial clearly missed its primary endpoint, and in a training study placebo performed better.

What rapamycin is

Rapamycin is a prescription drug; under the name sirolimus it is approved for transplant medicine. Its use to extend healthspan takes place outside this approval, usually at low doses and weekly rather than daily.

What is rated is the state of knowledge, not the substance: the signaling pathway is one of the best understood in aging research, but mechanism and proof of effect are two separate questions.

How it is supposed to work

Rapamycin binds the protein FKBP12 and through it blocks the kinase mTORC1, a central switch for cell growth. The inhibition mimics the state of calorie restriction and activates autophagy, the cellular recycling of damaged components.

In model organisms, this pathway is convincingly established. In humans, endpoint data on aging are lacking; off-label use runs ahead of the evidence.

What has been tested in humans

A systematic search of Europe PMC and ClinicalTrials.gov found no randomized trial in healthy people with a hard endpoint – that is, death, heart attack, dementia or bone fracture. The largest registered trial included 129 participants.

What exists are small studies with body composition or muscle function as the outcome. Two of them failed their prespecified main comparison.

What is well supported

An approved drug with established clinical use. As sirolimus, the drug is approved in transplant medicine and available by prescription only. Its use in humans has therefore been documented under medical supervision for decades – for an indication that has nothing to do with the longevity question, but that establishes the origin, quality and tolerability profile of the substance well.
The mechanism of action is understood at the molecular level. Rapamycin binds the protein FKBP12 and through it inhibits the kinase mTORC1, the central switch for cell growth. This signaling pathway is one of the best understood in aging research, and lifespan extension in model organisms is convincingly established. What is missing is the translation to humans – not the understanding of the pathway.
The main longevity trial was well designed. PEARL (Moel 2025, NCT04488601) was decentralized, double-blind and randomized, included 129 healthy adults over 48 weeks and tested a prespecified primary endpoint, visceral fat by DXA. That this endpoint was missed – partial eta squared 0.001 at p=0.942 – is a robust result, not a data gap: the question was asked and answered.
The second study also reports in full. RAPA-EX-01 (Stanfield 2026) disclosed, for 40 people aged 65 to 85 over 13 weeks, both the intention-to-treat analysis (−2.13 repetitions; 95% CI −4.61 to 0.34; p=0.089) and the per-protocol analysis (−3.44; −5.86 to −0.99; p=0.007), and counted adverse events separately (99 versus 63). The data are thin, but what exists can be verified.

What the studies show

PEARL: primary endpoint clearly missed

In the decentralized, double-blind PEARL trial (Moel 2025), 129 healthy adults received 5 or 10 mg of rapamycin per week or placebo for 48 weeks. The primary endpoint was visceral fat, measured by DXA. It was not met: partial eta squared 0.001 at p=0.942, practically no difference. The positively reported findings on lean mass in women on 10 mg (partial eta squared 0.202; p=0.013) and on pain (0.168; p=0.015) come from exploratory subgroups and are hypotheses, not results. Conflict of interest: the sponsor of the trial was AgelessRx, a company that sells the drug; authors of the paper are affiliated with it.

Training study: placebo performed better

In the RAPA-EX-01 study (Stanfield 2026), 40 people aged 65 to 85 received 6 mg of sirolimus per week or placebo for 13 weeks, each in addition to a home training program. The primary endpoint, the 30-second sit-to-stand test, was missed: in the intention-to-treat analysis, that is, with all randomized participants, the result was −2.13 repetitions (95 percent confidence interval −4.61 to 0.34; p=0.089) – the direction favors placebo. Among participants who followed the protocol, the difference was statistically significant, also in favor of placebo: −3.44 (−5.86 to −0.99; p=0.007). The 6-minute walking distance did not differ (−4.87 meters; −28.97 to 19.71; p=0.706).

Review: no evidence as a senotherapeutic

A review by Hands (2025) states that the human data so far do not show that rapamycin is a proven senotherapeutic – that is, an agent that selectively removes aged cells that can no longer divide. This means the bridge between animal data and the expectations of users is missing.

Where the data stop

No effect on lifespan or disease incidence in humans. PEARL explicitly does not show this, and there is no study in healthy people with a hard endpoint.
No demonstrated gain in muscle mass or pain relief. The figures from PEARL come from exploratory subgroups after a failed main comparison and would first have to be tested in a dedicated study.
No confirmation of the training hypothesis. In RAPA-EX-01, the advantage was with placebo. An added benefit for training is therefore not just unproven but contradicted by the only available study.
No evidence as a senotherapeutic. The 2025 review states exactly that.

Status, approval and legal situation

As sirolimus (Rapamune), the drug is approved for transplant medicine and available by prescription only. Any use to extend healthspan is off-label use, meaning use outside the tested indication. Gray-market sources bypass medical supervision and quality control of the product.

Safety

In RAPA-EX-01, 99 adverse events were documented under sirolimus compared with 63 under placebo. One serious event, a case of pneumonia, was classified as possibly drug-related. With 40 participants over 13 weeks, no measure of risk can be derived from this, but the direction can: the side-effect burden was higher in the active-treatment group.

With continuous use, rapamycin suppresses the immune system; pulsed protocols are meant to mitigate this, but this has not been tested. Blood sugar and blood lipids are considered parameters to monitor. This text does not replace medical advice and contains no dosage recommendation.

BK-Score Thin human evidence

Human evidence		5
Mechanism		9
Safety data		5
Hype gap		4
Track record of use		9

The mTOR pathway is one of the best understood in aging research and convincing in model organisms. In humans, there are approved uses in transplant medicine but no longevity endpoint data; off-label use runs ahead of the evidence.

The score rates the state of knowledge, not the substance. “Safety data 9” means well studied – not harmless. “Track record of use 9” means used long and widely – that is not proof of efficacy.
Subjective assessment by Biohacking Kompakt based on published scoring rules – not a scientific rating and not a medical recommendation. Rules and all ratings (German)

Frequently asked questions about rapamycin (sirolimus)

Does rapamycin really work against aging?

In humans, this has not been shown. There is no randomized trial in healthy people that has examined a hard endpoint such as death, heart attack or dementia. The largest registered trial included 129 people and missed its own main goal. The convincing lifespan-extension data come from model organisms, not from human research.

What did the PEARL trial find?

PEARL clearly missed its primary endpoint. In 129 healthy adults over 48 weeks, visceral fat showed an effect size of partial eta squared 0.001 at p equal to 0.942, meaning practically no difference from placebo. The positively reported results on lean mass and pain come from exploratory subgroups and count as hypotheses.

Who funded the PEARL trial?

The sponsor was AgelessRx, a company that sells rapamycin. Authors of the publication are affiliated with it. A conflict of interest does not automatically invalidate a study, but it has to be taken into account when interpreting it, especially when a failed main comparison takes a back seat to positive secondary findings in how the results are communicated.

Does rapamycin improve the effects of strength training?

No, in the only available study it was the other way around. In RAPA-EX-01, 40 people aged 65 to 85 received sirolimus or placebo in addition to home training. In the sit-to-stand test, the advantage was with placebo, at minus 3.44 repetitions and p equal to 0.007 in the per-protocol analysis. Walking distance did not differ.

What side effects does rapamycin have?

In the training study, 99 adverse events occurred under sirolimus compared with 63 under placebo. One serious event, a case of pneumonia, was considered possibly drug-related. With continuous use, the drug suppresses the immune system. Safety data from controlled trials on low-dose, pulsed use over years are entirely lacking.

Is rapamycin approved in Germany?

As sirolimus, the drug is approved for transplant medicine and available by prescription only. There is no approval for use to extend healthspan; such use is off label, meaning outside the tested indication. Gray-market sources bypass medical supervision and quality control of the product.

The podcast episode (in German)

Episode 30

Rapamycin: mTOR, Easter Island & the star of longevity research

The podcast by Paul Höser (Episode 30) · with Paul & Paula. A fresh, upbeat AI dialogue episode about the hottest longevity candidate: from the Easter Island soil sample (1964) to the mTOR switch that trades growth for cellular cleanup (autophagy). With the milestones Harrison (Nature 2009, +9–14 % lifespan in mice), the PEARL human trial (2024) and the everolimus vaccine study (Sci Transl Med 2014) – and why low & pulsed rather than high & daily is the key. Information only, no dosage or usage recommendation – off-label, prescription only.

Listen on Spotify

Same topic area: metabolic pathwayMetformin

Sources

Open in the database – with search, filters and comparison (German app)

Information only, not medical advice and no usage or dosage recommendation. Prescription and unapproved drugs belong in the hands of a physician. Last updated: 2026-09-13.