Here is a commentary on rapamycin research results (only available in PDF format, I'm afraid to say), which you might compare with an earlier commentary on the same work: "Anisimov et al. report that lifelong administration of rapamycin, starting at 2 mo of age, increases the maximum lifespan of female 129/Sv mice. This finding corroborates, in a different genetic background, the landmark discovery by the National Institute on Aging Intervention Testing Program (ITP) that rapamycin increases mouse lifespan in both sexes when given orally starting at either 9 or 20 mo of age. In contrast to the ITP study, Anisimov et al. administered rapamycin via subcutaneous injection, following a schedule of three injections per week for 2 weeks, followed by a 2 week break. The efficacy of this protocol suggests the intriguing possibility that intermittent administration may be one means of addressing potential side effects of chronic rapamycin usage, an obstacle to the clinical translation of these findings to a practical anti-aging drug in humans. Rapamycin is widely used clinically to suppress immune function during organ transplants, in addition to its use as an anticancer agent. Indeed, the established clinical use of this drug and its analogs represents a crucial opportunity in facilitating the move from basic research on the biology of aging toward agents that could prolong 'healthspan' by protecting against a wide spectrum of age-related diseases, while potentially extending the maximum human lifespan."