Rapamycin is primarily used in medicine as an immunosuppressant to prevent rejection in organ transplant patients. It works by inhibiting the mTOR pathway, which is crucial for cell growth and proliferation. This mechanism also makes it effective in treating certain types of cancer, as it can slow the growth of tumor cells. Additionally, Rapamycin is being researched for its potential to extend lifespan and delay age-related diseases, showing promise in studies on various organisms. In dermatology, it is used in topical formulations to treat conditions like facial angiofibromas in patients with tuberous sclerosis complex. Its ability to modulate immune responses and cell growth continues to make it a valuable compound in both clinical and research settings.