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Open WellbeingWhat the studies actually measured

Joints, muscles and pain

Collagen peptidesand Joint pain (osteoarthritis)

Both sources here measured lower joint pain (osteoarthritis).

How sure anyone can be

Low certainty, level 2 of 4

Further research is likely to change this.

The most certain of the two findings here; each record carries its own.

The numbers reported

One source’s range, drawn against its own line of no difference and scaled to its own numbers.

-20.67-13.63-6.58

This range stays on one side of the no-difference line.

Bar the confidence interval — the range the true effect is likely to sit inNotch the number the source reportedLine where there would be no difference at all

Two sources, newest first

What we read is the published abstract, not the full paper, so a blank below may still be printed in the paper itself. A fixed rule worked this out from the source’s own fields. Nobody checked this rating by hand.

  • Systematic review, 2025 · 11 studies pooled · 870 participants

    Low certainty, level 2 of 4

    Effect of collagen supplementation on knee osteoarthritis: an updated systematic review and meta-analysis of randomised controlled trials.

    Clin Exp Rheumatol. 2025;43(1):126-134. doi:10.55563/clinexprheumatol/kflfr5. PMID:39212129.

    Number reported
    -13.63
    Which way it went
    Lower
    Likely range
    -20.67 to -6.58
    Source’s own words
    mean difference in knee osteoarthritis pain score vs placebo (pooled across VAS/WOMAC pain scales)
    Who was studied
    Adult with knee osteoarthritis
    Compared with
    placebo
    Amount taken
    Not in the abstract
    For how long
    Not in the abstract
    Disagreement between studies
    I2=88%
    Kind of record
    Journal article
    How this rating was reachedstarts at High, 2 steps down: imprecision and inconsistency
    1. Starts at High
    2. Imprecision brought it down to Moderatethe interval excludes no effect but spans a 3-fold range of effect size, from trivial to largeReported in the abstract
    3. Inconsistency brought it down to Lowheterogeneity across pooled studies is high (I² = 88%)Reported in the abstract
    4. Ends at Low2 steps down.
    Checked, nothing to step it down for
    risk of bias and indirectness

    Imprecision stops at the first check that applies; others may apply too.

    AI review could not confirm it — an AI agent re-read this finding against the saved source and at least one check failed. The batch record names the check and quotes the sentence that caused the doubt. No person read it.

    Read the abstract on PubMed

  • Systematic review, 2023 · 4 studies pooled · 507 participants

    Very low certainty, level 1 of 4

    Analgesic efficacy of collagen peptide in knee osteoarthritis: a meta-analysis of randomized controlled trials.

    J Orthop Surg Res. 2023;18(1):694. doi:10.1186/s13018-023-04182-w. PMID:37717022.

    Number reported
    -0.58 standardised effect size
    Which way it went
    Lower
    Likely range
    -0.98 to -0.18
    Source’s own words
    standardized mean difference in knee osteoarthritis pain vs placebo
    Who was studied
    Adult with knee osteoarthritis
    Compared with
    placebo
    Amount taken
    Not in the abstract
    For how long
    Not in the abstract
    Disagreement between studies
    I2: 68%
    Kind of record
    Journal article
    How this rating was reachedstarts at High, 3 steps down: risk of bias, imprecision and inconsistency
    1. Starts at High
    2. Risk of bias brought it down to Moderatethe abstract's own appraisal reports serious study limitationsReported in the abstract
    3. Imprecision brought it down to Lowthe interval excludes no effect but spans a 5-fold range of effect size, from trivial to largeReported in the abstract
    4. Inconsistency brought it down to Very lowheterogeneity across pooled studies is high (I² = 68%)Reported in the abstract
    5. Ends at Very low3 steps down.
    Checked, nothing to step it down for
    indirectness

    Imprecision stops at the first check that applies; others may apply too.

    AI-reviewed & signed — an AI agent re-read this finding against the saved source and checked that the quote, the numbers, the units and the direction match it. No person read it. The owner authorised the agent to sign the batch with the owner's key, and every build rechecks that signature against these exact bytes.

    Read the abstract on PubMed

What is still missing from these readings

  • Amount taken — Not in the abstract.
  • For how long — Not in the abstract.

Something nobody wrote down is never a zero and never a guess.

Still to read for Collagen peptides

Two of the seven things on our list for Collagen peptides have no reading here yet:

  • Heart Rate (Continuous)
  • Interleukin-6

Still to read means nobody here has got to it, not that it was tried and did nothing or that no research exists. A pairing on no list is not a gap: we never set out to read it.

Read next

This is a library, not advice. No recommendation, no dose, no diagnosis, no ranking. We never ask about your symptoms, and nothing here is tailored to you.