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Open WellbeingWhat the studies actually measured

Liver, kidney and digestion

Creatineand Estimated GFR

Both sources here found no clear difference in estimated GFR.

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.

-15-5.24.6

This range crosses the no-difference line, so these numbers fit a real difference and no difference at all equally well.

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, 2026 · 8 studies pooled

    Low certainty, level 2 of 4

    The effect of creatine supplementation on kidney function: a systematic review and meta-analysis of randomized controlled trials.

    J Ren Nutr. 2026. doi:10.1053/j.jrn.2026.04.010. PMID:42035842.

    Number reported
    -5.2
    Which way it went
    No clear difference
    Likely range
    -15 to 4.6
    Source’s own words
    mL/min/1.73 m2 eGFR, mean difference versus control (not statistically significant)
    Who was studied
    Adult
    Compared with
    placebo
    Amount taken
    Not in the abstract
    For how long
    Not in the abstract
    Disagreement between studies
    Not in the abstract
    Kind of record
    Journal article
    How this rating was reachedstarts at High, 2 steps down: risk of bias and imprecision
    1. Starts at High
    2. Risk of bias brought it down to Moderatethe abstract reports no risk-of-bias or quality appraisal, so study limitations cannot be ruled outNot in the abstract
    3. Imprecision brought it down to Lowthe confidence interval includes no effectReported in the abstract
    4. Ends at Low2 steps down.
    Checked, nothing to step it down for
    indirectness
    Inconsistency
    No high disagreement reported between the 8 studies it pooled

    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

  • Randomised trial, 2020

    Low certainty, level 2 of 4

    Novel renal biomarkers show that creatine supplementation is safe: a double-blind, placebo-controlled randomized clinical trial.

    Toxicol Res (Camb). 2020;9(3):263-270. doi:10.1093/toxres/tfaa028. PMID:32670557.

    Number reported
    Not in the abstract
    Which way it went
    No clear difference
    Likely range
    Not in the abstract
    Source’s own words
    between-group difference in eGFR after 35 days (magnitude not reported in abstract)
    Who was studied
    Healthy young active male university students
    Compared with
    placebo
    Amount taken
    3 to 5 g/d creatine in separate 3 g/d and 5 g/d groups
    For how long
    35 days
    Disagreement between studies
    Not in the abstract
    Kind of record
    Journal article
    How this rating was reachedstarts at High, 2 steps down: risk of bias and imprecision
    1. Starts at High
    2. Risk of bias brought it down to Moderatethe abstract reports no risk-of-bias or quality appraisal, so study limitations cannot be ruled outNot in the abstract
    3. Imprecision brought it down to Lowthe abstract reports no confidence interval for the estimateNot in the abstract
    4. Ends at Low2 steps down.
    Checked, nothing to step it down for
    indirectness
    Inconsistency
    One study, so there was nothing to disagree

    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

  • One give no number at all, only which way it went.
  • One gives no likely range, so how precise that number is is unknown.
  • Two do not say how many people took part.
  • Amount taken — One of Two readings: Not in the abstract.
  • For how long — One of Two readings: Not in the abstract.

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

Still to read for Creatine

Five of the 14 things on our list for Creatine have no reading here yet:

  • Estimated VO2max
  • Heart rate variability (RMSSD)
  • Resting heart rate
  • Total sleep time
  • Total testosterone

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

  • Creatine

    Eight other questions read for it

  • Liver, kidney and digestion

    22 questions read under it

  • Estimated GFR

    No other ingredients read against it

    Alphabetical, and by nothing else.

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.