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Open WellbeingWhat the studies actually measured

Energy and exercise

Creatineand Creatine Kinase (CK)

Two sources here, and they say different things: one found no clear difference in creatine Kinase (CK) and one reported mixed results.

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.

-121.5567.38256.31

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

We do not pick between these or average them into one number.

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, 2022

    Very low certainty, level 1 of 4

    The Paradoxical Effect of Creatine Monohydrate on Muscle Damage Markers: A Systematic Review and Meta-Analysis.

    Sports Med. 2022;52(7):1623-1645. doi:10.1007/s40279-022-01640-z. PMID:35218552.

    Number reported
    -1.09 standardised effect size
    Which way it went
    Mixed results
    Likely range
    Not in the abstract
    Source’s own words
    standardised mean difference in indirect muscle damage markers at 48-90 h post-exercise (acute training response)
    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, 4 steps down: risk of bias, indirectness, imprecision and inconsistency
    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. Indirectness brought it down to Lowthe outcome measured is a proxy for the target outcomeReported in the abstract
    4. Imprecision brought it down to Very lowthe abstract reports no confidence interval for the estimateNot in the abstract
    5. Inconsistency — already at Very low, the lowest rungpooled studies disagree on the direction of effectReported in the abstract
    6. Ends at Very low4 steps down.

    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, 2018

    Low certainty, level 2 of 4

    Creatine supplementation does not alter the creatine kinase response to eccentric exercise in healthy adults on atorvastatin.

    J Clin Lipidol. 2018;12(5):1305-1312. doi:10.1016/j.jacl.2018.05.018. PMID:29945780.

    Number reported
    67.38
    Which way it went
    No clear difference
    Likely range
    -121.55 to 256.31
    Source’s own words
    U/L, source-reported group mean difference in absolute peak CK change relative to baseline after eccentric exercise; subtraction order is not stated in the abstract
    Who was studied
    Healthy nonsmoking adult taking high dose atorvastatin
    Compared with
    atorvastatin 80 mg/d plus placebo
    Amount taken
    10 g/d creatine monohydrate plus atorvastatin 80 mg/d
    For how long
    28 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 confidence interval includes no effectReported 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 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

What is still missing from these readings

  • 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

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.