It's so frustrating to get seemingly contradictory results across species with the same treatment. The Interventions Testing Program found no increase in median or maximum lifespan in mice, male or female, treated with metformin (though it did in combination with rapamycin) [0].

I realize "decelarating the aging clock" might be subtly different than increasing lifespan, but it's a reasonable enough comparison, imho. Hopefully we can soon capitalize on improvements in AI to faithfully model human biology in silico, and conduct experiments that way.

[0] https://www.nia.nih.gov/research/dab/interventions-testing-p...