17α-Estradiol (17αE2) is a non-aromatizable estrogen that activates estrogen receptor-α and -β with minimal uterotrophic activity, thereby engaging classical ER-mediated transcriptional pathways without systemic feminization. The compound modulates multiple aging pathways including mitochondrial function, oxidative stress resistance, and NAD+ metabolism through both genomic and rapid non-genomic ER signaling. In preclinical models, 17αE2 extends lifespan in male mice by 5-10% and improves healthspan metrics including metabolic flexibility, muscle mass retention, and vascular endothelial function. Limited human data suggest improvements in cardiometabolic markers and insulin sensitivity, though longevity effects in humans remain uncharacterized and require prospective clinical investigation.
17α-estradiol is a non-feminizing estrogen studied primarily in male longevity research, distinct from the 17β-estradiol used in conventional hormone therapy. It is not FDA-approved for any longevity indication.
Interventions Testing Program (ITP) data has shown lifespan extension in male mice specifically. Human trial recruitment is tracked in the full profile as it becomes available.
Current ITP lifespan data for 17α-estradiol has not shown the same effect in female mice, an important caveat reflected directly in Geroevidence's profile rather than omitted.
As a non-feminizing estrogen studied primarily in preclinical models, comprehensive human safety data — including any hormonal effects — is not yet established.
Sex-specific differences in baseline estrogen physiology are thought to underlie this pattern; the mechanistic basis for the sex-specific lifespan effect remains an active area of research.