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Longevity supplements › Metformin and Aging › Studies

Animal study

In worms and lab-grown human cells, metformin given late in life shortened lifespan

Espada and colleagues · Nature metabolism · 2020

Original title: Loss of metabolic plasticity underlies metformin toxicity in aged Caenorhabditis elegans.

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What the study found

Points to harm

Metformin shortened lifespan when provided in late life, contrary to its positive effects in young organisms. In aged worms and late-passage human cells it caused lethal ATP exhaustion.

The study at a glance

Type of study
Animal study
Who or what was studied
Roundworms (C. elegans) of different ages and human cells grown in dishes
What was tested
Metformin given early or late in life, and to young vs old cells
What it measured
The question itself: aging, frailty and death in people without diabetes
Trial registration
10.6084/m9.figshare.c.5124524
Who has a stake
No disclosure in PubMed
No disclosure in PubMed.
Journal
Nature metabolism, 2020
Source
PubMed record 33139960. This page is based on the abstract only.

How much this study counts

  • –Done in animals. Results in animals often do not carry over to people.
  • •The PubMed record has no conflict-of-interest statement.
  • •Summarized from the PubMed abstract only. The full paper may hold details the abstract leaves out.

✓ Strength– Limit• Note

These points come from fixed rules about the type of study, its size and length, what it measured, and who has a stake. Every study on Digestery gets the same rules.

Where this study sits

Each dot is one on-topic paper on this question. Steps near the top answer the question more directly.

↑ Stronger evidence

  1. Trials in people: aging and age-related disease

    1

    1 benefit

  2. Trials in people: other measures

    3

    2 no difference, 1 harm

  3. Trials in people: lab tests or safety

    6

    2 benefit, 2 mixed, 2 no difference

  4. Population studies

    8

    6 benefit, 2 no difference

  5. Blood levels and genes

    0

    None among the papers we read.

  6. Animals

    3

    2 benefit, 1 harm

    ↑ This study is the ringed dot

↓ Weaker evidence

  • Points to benefit
  • Mixed
  • No difference
  • No direction
  • Points to harm

How it fits with the other research

The short answer to “Does metformin slow aging in people without diabetes?”

Not shown in people without diabetes.

Confidence: low. Based on 26 on-topic papers.

Read the full answer

Of the other 2 papers on the same step: 2 benefit. This one found harm. It differs from most of them.

  • Quoted in “What we found”: Animal results split: metformin at 0.1% of food from middle age lengthened life in male mice, but metformin given late in life shortened life in worms.
  • Part of the finding “Animals: longer life in mice, shorter in old worms”.
  • Marked as a key paper in the research timeline: Late-life metformin shortened lifespan in worms.
  • On the watch list: Large aging trials in people without diabetes.

Other papers on the same step

See all 26 studies on this question

How this page was made

Label

First read of the abstract
Claude Sonnet
Independent second read
Claude Haiku
Differences settled
The two reads agreed on every checked field. Claude Opus 5.5.
Headline
Claude Sonnet, from the checked study record. A script checked its numbers and wording.
Numbers
Checked against the abstract by a script
“How much this study counts”
Fixed rules, the same for every study
Source check by a person
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