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Longevity supplements › Urolithin A and Muscle › Studies

Randomized trial · measured other health measures

8-week trial in 20 male lifters: no clear max-lift gain, more reps to failure

Zhao and colleagues · Journal of the International Society of Sports Nutrition · 2024

Original title: Assessment of Urolithin A effects on muscle endurance, strength, inflammation, oxidative stress, and protein metabolism in male athletes with resistance training: an 8-week randomized, double-blind, placebo-controlled study.

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

Mixed

Versus placebo, bench press and squat maximums rose but not clearly (p = 0.462; p = 0.710). Isometric strength (p = 0.048) and reps to failure (p = 0.011) improved more. CRP fell more (p = 0.032).

The study at a glance

Type of study
Randomized trial
Who or what was studied
20 people · 20 male athletes who do weight training
What was tested
1 g urolithin A a day for 8 weeks, vs placebo
What it measured
Several kinds of outcomes
Daily amount
1 g a day
How long
8 weeks
Who has a stake
No stake declared
No potential conflict of interest was reported.
Journal
Journal of the International Society of Sports Nutrition, 2024
Source
PubMed record 39487653. This page is based on the abstract only.

How much this study counts

  • ✓Randomized: people were put into groups by chance, so the groups start out alike.
  • ✓Compared with a placebo, a dummy treatment.
  • –Small: 20 people. Small trials can miss real effects or find chance ones.
  • –Short: 8 weeks. Longer-term effects are unknown.
  • •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

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: 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

    ↑ This study is the ringed dot

  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

Of the other 3 papers on the same step: 2 mixed, 1 no difference. This one found mixed. It agrees with most of them.

  • Quoted in “What we found”: Four placebo-controlled trials in people tested urolithin A on muscle: two in middle-aged or older adults (one with 66 people) and two in trained male athletes (20 and 42).
  • Quoted in “What we found”: Three trials gave 1000 mg (1 g) a day; one compared two doses with placebo. Trials lasted from 4 weeks to 4 months.
  • Part of the finding “Strength rose in some tests, not others”.
  • Open item for a person: Zhao 2024: CRP rose from baseline in the urolithin A group yet fell versus placebo; check the full text.

Other papers on the same step

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 reviewer corrected 2 fields after reading the abstract. 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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