# Semaglutide Lifespan Study in Female Mice: 742 vs 834 Days | This GLP A Nature study found late-life semaglutide extended median lifespan in female mice from 742 to 834 days, outperforming a matched 24% calorie restriction on several measures. No human data exists. Publisher: This GLP Editorial Team Canonical: https://thisglp.com/research/semaglutide-lifespan-in-mice Updated: 2026-09-18 Published: 2026-09-16 [← Research](https://thisglp.com/research) Evidence # Semaglutide Lifespan Study in Female Mice: 742 vs 834 Days Semaglutide started late in life extended median lifespan from 742 to 834 days in female mice, and beat a calorie-restricted group matched to how much less they ate. [This GLP Editorial Team](https://thisglp.com/about)September 20267 min readUpdated September 2026 Median lifespan, female mice · vehicle · 742 days · semaglutide · 834 days · 92 days apart — and the comparison arm ate 24% less too · Treatment started at 20 months of age. No human data exists. **Research, not medical advice.** This GLP is independent and educational. Nothing here is a substitute for individualized care from a licensed clinician, and reading it creates no doctor–patient relationship. Talk to your own provider before starting, stopping, or changing any medication, peptide, or therapy. See our [methodology](https://thisglp.com/methodology) and [terms](https://thisglp.com/terms). ## Key takeaways - This is a mouse study. Female C57BL/6 mice, one strain, treated daily from 20 months of age. - Median lifespan was 742 days on vehicle and 834 days on semaglutide. - The semaglutide regimen cut food intake by 24%, and a comparison group was calorie-restricted by the same 24%. - Against that matched restriction, semaglutide did better on exploration, spatial memory and glucose control. - No trial has asked whether any of this happens in a person. Nothing in this paper is a reason to buy a GLP-1, and it is going to be reported as one. What it is, is the first careful attempt to separate a drug’s effect on aging from the effect of simply eating less — and it is the outcome that [the surrogate-marker literature keeps standing in for](https://thisglp.com/research/do-glp1-drugs-slow-aging), measured directly, in animals. ## What was done Female mice of a single common laboratory strain were given daily semaglutide by injection starting at twenty months of age, which is late middle age for a mouse rather than the start of life. [\[1\]](https://thisglp.com/research/semaglutide-lifespan-in-mice#ref-1) Treatment continued for the rest of their lives. Median lifespan came out at 742 days in the vehicle group and 834 days on semaglutide, compared by log-rank test. The gap of 92 days, about 12%, is this desk’s subtraction from those two published figures rather than a number the paper prints. Why the calorie-restriction arm matters so much Eating less is the oldest and most reliable way known to extend life in a laboratory animal, and a drug that suppresses appetite will do that by default — so a lifespan result from an appetite suppressant tells you nothing on its own about the drug. The authors measured how much less their mice ate, found 24%, and then ran a separate group restricted by exactly that 24% for five months as the comparison. Against it, semaglutide preserved baseline function, tracked calorie restriction on most measures, and did better on exploratory drive, spatial memory and glucose control. That is the part of the paper that is actually new. ## What it also found Three months of treatment improved physiological function, attenuated recognized hallmarks of aging, and shifted nutrient-sensing pathways and conserved genetic regulators of aging in the direction calorie restriction shifts them. The authors read the whole picture as semaglutide acting like a calorie-restriction mimetic, with some effects beyond what reduced intake explains — which is a mechanistic claim about mice, and a different kind of evidence from [a biomarker moving in people](https://thisglp.com/research/glp1-pcos-insulin-resistance). ## Every reason to hold it loosely Female mice only, one strain, one laboratory. Strain and sex both change lifespan results in this field routinely, and a finding in female C57BL/6 mice is a finding in female C57BL/6 mice until somebody repeats it elsewhere. The schedule is not a human schedule either. These animals were injected daily; people take semaglutide weekly, at doses that do not map across species by any simple ratio. Drugs that extend rodent lifespan have a long history of not doing so in humans, and there is no registered trial asking this question in people. ## What a reader should take from it That the mechanism question is now genuinely open, and that it was mostly closed before this — the reasonable default was that any longevity effect of these drugs is a weight effect wearing a lab coat. This is real evidence against that default, in mice. What it is not is a purchase. The drugs on this site are sold for weight, at prices set by sellers, to people who will take them for a year or two at most, and [what happens outside a controlled study](https://thisglp.com/research/glp1-weight-loss-in-ordinary-care) looks nothing like a mouse facility. A first-in-class result has to survive a long way before it means anything at a checkout — the same distance [an early-phase weight figure](https://thisglp.com/research/triple-agonist-first-in-human) has to travel. ## Frequently asked Does semaglutide extend lifespan? In female mice of one strain, started at twenty months, median lifespan went from 742 to 834 days. Nothing equivalent has been measured in people, and no trial is asking. Is it just because the mice ate less? That is the question the study was built to answer. Semaglutide cut food intake by 24%, and a separate group was restricted by the same 24% — against it, the drug still did better on exploration, spatial memory and glucose control. How much longer is 92 days for a mouse? About 12% on the vehicle group's median. That percentage is arithmetic from the two published figures, not a number the paper reports. Should this change what I do? No. It was daily injection in mice at doses that do not translate across species, and rodent lifespan results have a long record of not carrying over to people. ## Sources 1. \[1\] Feng Y, et al. (2026). Late-life semaglutide treatment slows ageing and extends lifespan in female mice Nature. [PMID 42686906](https://pubmed.ncbi.nlm.nih.gov/42686906/) ## Where to get it ### Best GLP-1 injections Every injectable seller we can verify, with the price each one publishes and an honest read of what the trials measured. 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