Thanks to @Krister_Kauppi for creating these summaries for lifespan increases (%) seen in males and females (started at different ages) from the data and testing results from the National Institutes on Aging Interventions Testing Program (ITP), the leading longevity drug / supplement testing program in the world.
Increasingly, the ITP is doing combination tests, such as the rapamycin + acarbose study that resulted in as much as a 37% median lifespan improvement (as shown at the top of the above graphic). In most of these studies the earlier that the drug was started (in terms of months of age), the larger the longevity benefit. We look forward to more tests like this, and many people here in our forums are already trying combinations of these drugs: New Paper: Lifespan Benefits for the Combination of Rapamycin plus Acarbose in mice
See discussion here: Best ITP longevity interventions