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Pooled review (meta-analysis)

Pooled review of 5 trials: urolithin A did not clearly change 6-minute walk distance

Dao and colleagues · Frontiers in nutrition · 2026

Original title: Effects of Urolithin A supplementation on muscle health outcomes in humans from randomized controlled trials.

Under review. A person has not yet checked this summary against the paper. It is written from the PubMed abstract. Until a person checks it, search engines are asked not to list this page.

What the study found

No difference

Pooling two trials for the 6-minute walk gave +17.03 m (95% CI -5.33 to 39.40 m; p = 0.135), low certainty. Strength, endurance and marker results were not pooled and called exploratory.

The study at a glance

Type of study
Pooled review (meta-analysis)
Who or what was studied
5 studies, 236 people · People in five small trials with different health backgrounds
What was tested
Urolithin A by mouth vs placebo, pooled for the 6-minute walk test
What it measured
Several kinds of outcomes
Who has a stake
No stake declared
Authors declared no commercial or financial relationships.
Journal
Frontiers in nutrition, 2026
Source
PubMed record 42559151. This page is based on the abstract only.

How much this study counts

  • ✓Pools the results of 5 studies with 236 people.
  • •A pooled review is only as strong as the studies it pools.
  • •Measured several kinds of outcomes.
  • ✓No competing interests declared.
  • •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

This paper is not on the ladder. It is a pooled review (meta-analysis), and reviews and opinion pieces discuss studies that are already counted on the steps below.

↑ Stronger evidence

  1. Trials in people: muscle strength and endurance

    0

    Not done yet. This is the step that would answer the question.

  2. Trials in people: other measures

    4

    3 mixed, 1 no difference

  3. Trials in people: lab tests or safety

    0

    None among the papers we read.

  4. Population studies

    0

    None among the papers we read.

  5. Blood levels and genes

    0

    None among the papers we read.

  6. Animals

    2

    2 benefit

  7. Cells in a dish

    1

    1 no direction

↓ 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 urolithin A improve muscle health with age?”

Unclear: small trials, mixed results.

Confidence: very low. Based on 9 on-topic papers.

Read the full answer
  • Quoted in “What we found”: A 2024 review said urolithin A raised strength and endurance; a 2026 pooled analysis called those results exploratory and found no clear walking gain.
  • Summed up in “What reviews found”: Combined five randomized trials (236 people). Only the 6-minute walk could be pooled, from two trials: +17.03 m, with a likely range of -5.33 to 39.40 m, which includes no effect. Certainty was rated low.
  • Marked as a key paper in the research timeline: Pooled analysis of five trials: walking gain unclear.
  • Open item for a person: Reviews Kuerec 2024 and Dao 2026 likely include trials Singh 2022 and Liu 2022; avoid counting the same trials twice.
  • Open item for a person: Singh 2022 abstract gives no sample size or doses; Dao 2026 mentions 500 mg and 1,000 mg arms of Singh et al.

Other reviews on this question

See all 9 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 differed. The reviewer checked the abstract and kept the first read. 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
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