17-a-estradiol late in life extends lifespan in aging UM-HET3 male mice; nicotinamide riboside and three other drugs do not affect lifespan in either sex - Harrison,DE; Strong,R; Reifsnyder,P; Kumar,N; Fernandez,E; Flurkey,K; Javors,MA; Lopez-Cruzan,M; Macchiarini,F; Nelson,JF; Markewych,A; Bitto,A; et al. (AGING CELL, 2021)