The Navel of the World -- see, they weren't kiddin' around.
“A key challenge is to avoid adverse side effects from continuous dosing.”
https://www.nature.com/articles/s43587-022-00278-w
Rapamycin for longevity: opinion article
Mikhail V. Blagosklonny
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6814615/
“Sirolimus, also known as rapamycin and sold under the brand name Rapamune among others, is a macrolide compound that is used to coat coronary stents, prevent organ transplant rejection, treat a rare lung disease called lymphangioleiomyomatosis, and treat perivascular epithelioid cell tumor (PEComa). It has immunosuppressant functions in humans and is especially useful in preventing the rejection of kidney transplants. It is a mechanistic target of rapamycin (mTOR) kinase inhibitor that reduces the sensitivity of T cells and B cells to interleukin-2 (IL-2), inhibiting their activity. This compound also has a use in cardiovascular drug-eluting stent technologies to inhibit restenosis.”
https://en.wikipedia.org/wiki/Sirolimus