A Mild Estrogen Extends Life in Male Mice, Not in Females
Graded Preliminary — a review without a systematic search whose findings come from mouse, rat and cell experiments; no studies in people exist yet.
Animal study. Findings may not carry over to people, which is why the grade is capped at Preliminary.
- Design
- Narrative review
- Participants
- N/A
- Duration
- —
- Funding
- National Institutes of Health (National Institute on Aging)
The mild estrogen 17-alpha-estradiol extended the lives of male mice but not of female mice.
A close chemical cousin of the female hormone estradiol helped male mice live longer. The hormone is called 17-alpha-estradiol, and it has only mild feminizing effects. A new review gathers what is known about it.
The key data come from a large US National Institute on Aging testing program run in three labs at once. At a first, lower dose, male mice lived 12 percent longer on average across sites, although two of the three labs saw no clear effect. At a higher dose the gain was 19 percent, while female lifespan did not change. Starting treatment late, at 16 or 20 months of age, still extended the males' lives. Treated males gained less weight, carried less body fat and responded better to insulin. In rats, the hormone curbed sugar production by the liver.
Why mainly males benefit is still unclear. Much points to one particular estrogen docking site on cells, but the exact route is unknown. One study found no harm to male mouse fertility. No clinical trials in people have tested its effects on metabolism or lifespan.
Conflict of Interest Disclosure: Two authors report funding from the US National Institutes of Health, a veterans' medical center and a research consortium.
Disclaimer: Research summaries are provided for informational purposes only and do not constitute medical advice. Always consult a qualified healthcare professional before making changes to your health routine.