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Pooled review (meta-analysis)

Pooled review of 23 trials: skin benefit overall, none in high-quality or independent studies

Myung and colleagues · The American journal of medicine · 2025

Original title: Effects of Collagen Supplements on Skin Aging: A Systematic Review and Meta-Analysis of 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

Mixed

All 23 trials together showed better hydration, elasticity and wrinkles. Studies not paid for by drug companies and high-quality studies showed no effect. The authors found no clinical evidence to support use.

The study at a glance

Type of study
Pooled review (meta-analysis)
Who or what was studied
23 studies, 1,474 people · Participants in 23 trials of collagen supplements for skin
What was tested
Collagen supplements compared with placebo, split by who paid for the study and by study quality
What it measured
The question itself: skin wrinkles, elasticity and hydration
Who has a stake
No disclosure in PubMed
No disclosure in PubMed.
Journal
The American journal of medicine, 2025
Source
PubMed record 40324552. This page is based on the abstract only.

How much this study counts

  • ✓Pools the results of 23 studies with 1,474 people.
  • •A pooled review is only as strong as the studies it pools.
  • ✓Measured the question itself: skin wrinkles, elasticity and hydration.
  • •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

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: wrinkles, skin elasticity and moisture

    15

    13 benefit, 2 mixed

  2. Trials in people: other measures

    1

    1 benefit

  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.

↓ 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 collagen reduce skin aging?”

Unclear; higher-quality trials found no effect.

Confidence: low. Based on 22 on-topic papers.

Read the full answer
  • Quoted in “What we found”: A 2025 review of 23 trials with 1474 people found benefits overall, but none in trials without drug-company funding or in high-quality trials.
  • Part of the finding “Benefit missing in independent and high-quality trials”.
  • Summed up in “What reviews found”: Pooled 23 randomized trials with 1474 people. Overall, collagen improved hydration, elasticity and wrinkles, but trials without drug-company funding and high-quality trials showed no effect. The authors found no clinical evidence to support collagen for skin aging.
  • Marked as a key paper in the research timeline: Turning point: no benefit in independent, high-quality trials.

Other reviews on this question

See all 22 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 1 field 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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