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Open WellbeingWhat the studies actually measured

Blood sugar and insulin

Magnesiumand Hemoglobin A1c

Both sources here measured lower hemoglobin A1c.

How sure anyone can be

Moderate certainty, level 3 of 4

Further research may 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.

-0.26-0.15 percentage points-0.03

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, 2026

    Moderate certainty, level 3 of 4

    Comprehensive Effects of Magnesium Supplementation on Cardiometabolic Risk Factors: A Systematic Review and Dose-Response Meta-Analysis.

    Nutrients. 2026;18(15). doi:10.3390/nu18152435. PMID:42588058.

    Number reported
    -0.15 percentage points
    Which way it went
    Lower
    Likely range
    -0.26 to -0.03
    Source’s own words
    percentage points HbA1c, weighted mean difference vs controls
    Who was studied
    Not stated in the abstract
    Compared with
    controls
    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, one step down: imprecision
    1. Starts at High
    2. Imprecision brought it down to Moderatethe abstract does not state how many participants were pooledNot in the abstract
    3. Ends at ModerateOne step down.
    Checked, nothing to step it down for
    risk of bias and indirectness
    Inconsistency
    No disagreement reported, and no count of studies behind it

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

    Source saved; quote checked byte-for-byte against it by software; no signature.

    Read the abstract on PubMed

  • Systematic review, 2022

    Low certainty, level 2 of 4

    The effects of oral magnesium supplementation on glycaemic control in patients with type 2 diabetes: a systematic review and dose-response meta-analysis of controlled clinical trials.

    Br J Nutr. 2022;128(12):2363-2372. doi:10.1017/S0007114521005201. PMID:35045911.

    Number reported
    -0.73 percentage points
    Which way it went
    Lower
    Likely range
    -1.25 to -0.22
    Source’s own words
    percentage points HbA1c, dose-response mean difference at 500 mg/d
    Who was studied
    Adult with type 2 diabetes
    Compared with
    not stated in the abstract
    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 abstract does not state how many participants were pooledNot in the abstract
    4. Ends at Low2 steps down.
    Checked, nothing to step it down for
    indirectness
    Inconsistency
    No disagreement reported, and no count of studies behind it

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

    Source saved; quote checked byte-for-byte against it by software; no signature.

    Read the abstract on PubMed

What is still missing from these readings

  • Two do not say how many people took part.
  • 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 Magnesium

Nine of the 21 things on our list for Magnesium have no reading here yet:

  • Atrial fibrillation incidence
  • Bone mineral density
  • Cognitive performance
  • Depression
  • Generalized Anxiety Disorder-7 (GAD-7)
  • Insomnia Severity Index
  • Patient Health Questionnaire-9 (PHQ-9)
  • Sleep efficiency
  • 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.