Rapamycin, also known as Sirolimus or Rapamune, is a synthetic compound originally isolated from the bacterium Streptomyces hygroscopicus. It belongs to the macrolide class of compounds and is not endogenously produced in humans. Rapamycin is primarily synthesized for pharmaceutical use and is classified as an mTOR (mechanistic target of rapamycin) inhibitor. Researchers have extensively studied its role in cellular growth, proliferation, and survival, making it a significant focus in metabolic and circadian hormone research. The primary physiological role of rapamycin is its ability to inhibit the mTOR pathway, which is crucial in regulating cell growth and metabolism. Researchers have found that rapamycin has potential applications in areas such as cancer therapy, immunosuppression, and longevity studies. Its ability to modulate immune responses has made it a valuable tool in preventing organ transplant rejection. Rapamycin acts by binding to the FK506-binding protein 12 (FKBP12), forming a complex that inhibits the mTOR complex 1 (mTORC1). This inhibition leads to a reduction in protein synthesis and cell proliferation, impacting various downstream pathways involved in cell growth and metabolism. The pharmacokinetic properties of rapamycin include a relatively long half-life, with oral administration resulting in a half-life of approximately 60 hours. It is metabolized primarily by the liver through the CYP3A4 enzyme and has variable bioavailability due to first-pass metabolism. Clinically, rapamycin is used as an immunosuppressant to prevent organ transplant rejection and is approved by regulatory agencies such as the FDA. It is also under investigation for its potential in treating certain cancers and age-related diseases. Its regulatory standing varies by country, with specific guidelines for its prescription and use.
Rapamycin acts on the mTOR pathway by forming a complex with FKBP12, which then inhibits mTORC1. This inhibition leads to decreased protein synthesis and cell proliferation, impacting cellular growth and metabolism.
| Formula | C51H79NO13 |
| Molecular Weight | 914.2 g/mol |
| CAS Number | 53123-88-9 |
| PubChem CID | 5284616 |
| Oral | Approximately 60 hours with variable bioavailability due to first-pass metabolism |
Bioavailability is affected by first-pass metabolism; primarily metabolized by CYP3A4
Temperature
Store at room temperature (15-30°C)
Light
Protect from light
Form
Stable in tablet form for extended periods
Notes
Avoid exposure to moisture
Rapamycin is poorly soluble in water but soluble in organic solvents such as ethanol.
🇩🇪DE
Prescription only (verschreibungspflichtig), not a controlled substance under BtMG.
🇺🇸US
FDA approved for use as an immunosuppressant; prescription required.
🇦🇺AU
TGA Schedule 4 (prescription only medicine).
🇬🇧UK
Prescription only medicine (POM) under MHRA guidelines.
Legal status information is provided for general reference only and may not reflect the most current regulatory changes. Always verify with official government sources before making any decisions.
Frontiers in aging · 2025
Researchers observed that rapamycin, an antibiotic from the 1970s, may have potential benefits for increasing lifespan. However, they also noted some drawbacks and highlighted the need for further research to fully understand its effects on longevity.
GeroScience · 2023
Researchers found that rapamycin, a drug typically used for other medical purposes, is being used off-label by some adults to potentially improve health and longevity. They observed initial evidence suggesting that rapamycin can be safely used in healthy adults, although more research is needed to fully understand its effects and side effects.
Oncotarget · 2023
Researchers observed that rapamycin and similar drugs may help prevent cancer by targeting pre-cancerous cells and slowing down aging. Studies in mice showed that rapamycin effectively delays cancer development, and its use in organ transplant patients supports its potential cancer-preventive effects. Further clinical trials are needed to explore its benefits for high-risk groups, such as smokers.
European archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery · 2022
Researchers observed that sirolimus may effectively treat children with large lymphatic malformations in the head and neck, potentially improving symptoms and reducing size. However, not all patients respond to the treatment, so decisions about its use should involve a team of specialists.
Transplantation proceedings · 2003
Researchers found that sirolimus, derived from a soil bacterium, has strong antifungal, anticancer, and immunosuppressive properties. It works by blocking a key protein that regulates cell growth, making it useful in preventing organ rejection after transplants.
Bulletin du cancer · 1999
Researchers found that rapamycin, an immunosuppressant, effectively targets cancer cells with minimal side effects in clinical studies. They also observed that CCI-779, a similar drug given intravenously, shows promise in fighting tumors without significant immune suppression and is currently being tested in early human trials.
Clinical biochemistry · 1998
Researchers found that Rapamune, an immunosuppressive drug being tested for kidney transplants, works by blocking certain cellular signals and slowing down cell growth. This unique action has sparked interest in understanding how it affects the immune system and its potential uses in medicine.
Therapeutic drug monitoring · 1995
Researchers found that Rapamune (Sirolimus) is an effective immunosuppressant that helps prevent organ rejection in transplant models. It works by interfering with specific cellular processes in T-cells, which are crucial for immune response. This mechanism involves blocking signals that would normally activate certain proteins involved in cell growth and division.
Current opinion in nephrology and hypertension · 1995
Researchers observed that rapamycin, an emerging immunosuppressive drug, shows promise in preventing organ rejection in transplant patients. The review highlights its biological properties and how it works in the body, along with its potential uses in therapy.
Log cycles, set reminders and visualize serum levels.
This page is for informational and research purposes only. All information is based on published scientific literature. Nothing on this page constitutes medical advice or replaces consultation with a qualified healthcare professional.