The drug rapamycin has been shown to extend lifespan in lab animals, yet rapamycin has also been linked to impaired glucose tolerance and insulin sensitivity, two hallmarks of diabetes. By teasing apart rapamycin's activity at the cellular level, researchers at Whitehead Institute and the University of Pennsylvania have determined that inhibiting only the protein cluster known as the mechanistic target of rapamycin complex 1 (mTORC1) prolongs life in mice without adversely affecting glucose tolerance or insulin sensitivity. With this novel understanding of how rapamycin produces its anti-aging effects, researchers may be able to develop a drug that specifically targets mTORC1, thereby promoting longevity while preventing the adverse effects associated with rapamycin.