Key takeaways:
In the 1960s, researchers on Easter Island were investigating local indigenous peoples’ claims that the soil has healing properties. After testing various soil samples, the researchers isolated a small molecule they believed was responsible for the effects. They named it rapamycin5, after the traditional name for the island, Rapa Nui. Since its discovery, rapamycin has been used in various settings, from an antifungal agent to more recently a beacon of hope in anti-aging medicine. Additionally, it is showing promise in extending lifespan and preventing neurodegenerative diseases such as Alzheimer’s.
From anti-rejection med to longevity enhancer
The transition from an antifungal to a potential longevity drug has been intriguing. Rapamycin, approved in 1999 for its immunosuppressant qualities, is still commonly used in kidney transplants to prevent organ rejection. However, a 2014 study1 on older adults revealed a paradox: at much smaller doses, rapamycin boosted the immune response to flu vaccinations, despite their age-related weakened immune function. This unexpected enhancement suggests that rapamycin might have broader applications for disease prevention in older adults, potentially making it a valuable tool in combating age-related declines in the human immune system.
How rapa works
To understand how rapamycin works, it’s important to understand the molecule that it targets: a cellular receptor named mTOR. mTOR is present in nearly all cells in the human body and is responsible for mediating pathways that regulate cell growth, metabolism, and survival. Inhibiting mTOR completely is catastrophic - it prevents cells from making energy, eventually leading to their death. However, partial inhibition means that mTOR has a harder time forming a cluster with other proteins, which makes the cell act as if it's not getting enough food. This starts a process where the cell breaks down unneeded or damaged parts, like proteins that aren't folded correctly, which can otherwise impair the cell’s ability to function. This leads to improved cellular survival and resilience and is particularly relevant to brain health since one of the main features of Alzheimer’s is the accumulation of misfolded amyloid beta protein plaques in neurons.
The partial inhibition of mTOR therefore shows potential for slowing down the progression of Alzheimer’s disease and improving the survival rate of neurons. Animal studies2,3 suggest that rapamycin may help mitigate or improve many of the pathologies associated with Alzheimer's disease and potentially restore cognitive function.
Growing evidence yet limited human trials
While animal studies have robustly demonstrated lifespan and healthspan extensions—with remarkable outcomes like a 20-30% increase in the lifespan of mice4—human data remains scarce. The gap in human trials can be largely attributed to the fact that rapamycin use for longevity is considered “off-label”. This means that the Federal Drug Administration (FDA) has not yet approved rapamycin for this use, which diminishes incentives for comprehensive research funding. However, the evidence from animal studies across a variety of species strongly suggests a significant potential for rapamycin in anti-aging treatments.
Rapamycin’s mainstream use
As mentioned earlier, the FDA has only approved rapamycin for use as an immunosuppressant. It’s important to recognize that rapamycin use for longevity is still considered experimental and will not be reimbursed by insurance. Because the FDA hasn’t established guidelines around its use, there is no single accepted protocol for rapamycin dosage. Given the drug’s complex effects, the risk of experiencing side effects is real. Nonetheless,many individuals already use rapamycin “off-label” under the supervision of a physician for its longevity benefits. This is a perfectly legitimate use of the molecule, even though there is a lot we have yet to learn.
A promising option for the future
Rapamycin offers a compelling glimpse into the future of longevity and neuroprotection. Although its journey from a soil sample to a potential anti-aging miracle has been gradual, the promise it holds could change the landscape of preventive health. As research continues, both the medical community and potential users must weigh the benefits against the uncertainties of translating animal model successes to human health outcomes.
Learn more
Listen to the Peter Attia Drive episode on rapamycin to learn more about the molecule, its history, how it works, and the most recent evidence on its effects.