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Pooled review (meta-analysis)

Pooled review of 10 trials, 646 people: collagen raised skin hydration and elasticity

Danessa and colleagues · Indian journal of dermatology, venereology and leprology · 2025

Original title: Effects of collagen-based supplements on skin's hydration and elasticity: A systematic review and meta-analysis.

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

Points to benefit

Collagen raised skin hydration (SMD 1.25 (CI: 0.77-1.74)) and elasticity (SMD 0.61 (CI: 0.21-1.02)). Risk of bias was generally unclear and results vary between studies.

The study at a glance

Type of study
Pooled review (meta-analysis)
Who or what was studied
10 studies, 646 people · 646 people in 10 randomized trials, mostly women
What was tested
Collagen supplements at 1-10 g/day, compared with control; median 3.5 g/day
What it measured
The question itself: skin wrinkles, elasticity and hydration
Who has a stake
No disclosure in PubMed
No disclosure in PubMed.
Journal
Indian journal of dermatology, venereology and leprology, 2025
Source
PubMed record 40826844. This page is based on the abstract only.

How much this study counts

  • ✓Pools the results of 10 studies with 646 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
  • Part of the finding “Reviews find better hydration and elasticity”.
  • Summed up in “What reviews found”: Pooled 10 randomized trials with 646 people; findings apply mostly to women. Collagen at 1-10 g/day raised hydration (SMD 1.25) and elasticity (SMD 0.61). Bias risk was generally unclear, and results varied between 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 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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