Scientists report that adult cells reprogrammed to become primitive stem cells, called induced pluripotent stem cells (iPSCs), make tiny ‘cargo packets’ able to deliver potentially restorative or repairing proteins, antibodies or other therapies to aged cells. They say the human iPSCs they studied produced much more of the packets, formally known as extracellular vesicles, than other kinds of adult stem cells commonly used for this purpose in research.