The Study
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
This study is like testing different medicines on groups of mice to see if they live longer. It's not a randomized test like flipping a coin to decide which mouse gets which medicine. The researchers found that one medicine (17-α-estradiol) seemed to help male mice live longer, but they can't prove the medicine actually caused the longer life - it could just be a coincidence. And even if it works for mice, that doesn't mean it will work for people.
Analysis score
Maximum 72 for a cohort study.
Where the score came from
Scientists tested five different pills to see if any could help mice live longer. One pill called 17-α-estradiol (a non-feminizing estrogen) worked really well for male mice - they lived about 19% longer when given the pill starting at middle age, and even 11% longer when started at older age. But it didn't help female mice at all. The other four pills (including nicotinamide riboside) didn't help mice of either sex live longer.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 513 / 100
Quality score
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
Key takeaways
Summary
Based on the study abstract and findings.
- 1This study shows that 17-α-estradiol can extend lifespan in male mice even when treatment starts in middle or older age.
- 2However, this is basic research in mice - we don't know if it would work the same way in humans, and the effect was only seen in males.
- 3Male mice given 17-α-estradiol lived 19% longer (started at 16 months) and 11% longer (started at 20 months).
- 4Maximum lifespan increased 7%.
- 5Female mice showed no benefit.
- 6Four other drugs showed no significant lifespan extension.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Aging Cell
Year
2021
Authors
D. Harrison, R. Strong, P. Reifsnyder, Navasuja Kumar, Elizabeth Fernandez, K. Flurkey, M. Javors, M. Lopez-Cruzan, F. Macchiarini, James F. Nelson, Alessandro Bitto, Amy L. Sindler, G. Cortopassi, K. Kavanagh, L. Leng, R. Bucala, N. Rosenthal, A. Salmon, Timothy M. Stearns, M. Bogue, Richard A. Miller
Related Content
Claims (10)
A popular anti-aging supplement called nicotinamide riboside (NR) was given to mice to see if it could help them live longer, but the study found it didn't extend their lifespan at the doses tested.
Scientists tested three different compounds at specific doses in mice to see if they could help the mice live longer, but none of them made a meaningful difference in how long the mice lived.
Scientists fed old male mice a special chemical called 17-α-estradiol and found they lived about 19% longer than mice that didn't get the chemical.
Scientists gave old male mice a special compound called 17-alpha-estradiol in their food starting at 20 months old (roughly equivalent to late middle age in humans), and the mice lived about 11% longer than mice that didn't get the compound.
Giving male mice a special compound called 17-α-estradiol when they were middle-aged (16 months) helped them live about 7% longer, specifically extending their maximum lifespan.
Scientists fed mice a special vitamin supplement called nicotinamide riboside in their food starting when the mice were middle-aged, then tracked how long they lived. The supplement didn't make the mice live longer.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.