Actuarial baseline, since Johnson turned 49 in August: on the SSA 2023 period life table for US males, 50,785 of the 91,565 alive at 49 reach 80, so 55%; 21% reach 90 and 1.1% reach 100. Part of the gap to this market's 77% is ordinary selection, since the richest 1% of US men live about 15 years longer at age 40 than the poorest 1% (Chetty et al., JAMA 2016). The rest is a bet that his regimen cuts his mortality hazard by roughly half from here, which is more than any drug has done in a controlled trial in any mammal (the best replicated effect, rapamycin in the NIA mouse program, is a 23 to 26% gain in median lifespan). Whether a regimen moves a survival curve at all is now being tested in dogs rather than people, because the answer arrives in about 4.6 years instead of 21. The arithmetic with sources (mine): https://w0lph.github.io/k9/why-dogs.html?v=2

Why the path to human longevity runs through dogs

Computed from the cited life tables and trials: a lifespan answer takes 4.6 years in dogs and 21 in people; dogs share our environment and diseases, lifespan has already been extended in dogs, and a regulator has accepted lifespan extension as an indication for dog drugs.

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