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Open WellbeingWhat the studies actually measured

Blood sugar and insulin

Quercetinand Fasting plasma glucose

Both sources here found no clear difference in fasting plasma glucose.

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

No number has been put on this yet. Two sources recorded only which way the numbers went — for now, that is all we have here.

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, 2023

    Low certainty, level 2 of 4

    The effects of Quercetin supplementation on cardiometabolic outcomes: An umbrella review of meta-analyses of randomized controlled trials.

    Phytother Res. 2023;37(11):5080-5091. doi:10.1002/ptr.7971. PMID:37654199.

    Number reported
    Not in the abstract
    Which way it went
    No clear difference
    Likely range
    Not in the abstract
    Source’s own words
    weighted mean difference in fasting plasma glucose vs comparison (no pooled estimate reported for the null result)
    Who was studied
    Not stated in the abstract
    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: imprecision and inconsistency
    1. Starts at High
    2. Imprecision brought it down to Moderatethe abstract reports no confidence interval for the estimateNot in the abstract
    3. Inconsistency brought it down to Lowheterogeneity across pooled studies is high (I² = 88.3%)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.

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

    Read the abstract on PubMed

  • Systematic review, 2019

    Low certainty, level 2 of 4

    Effects of quercetin supplementation on glycemic control among patients with metabolic syndrome and related disorders: A systematic review and meta-analysis of randomized controlled trials.

    Phytother Res. 2019;33(5):1330-1340. doi:10.1002/ptr.6334. PMID:30848564.

    Number reported
    Not in the abstract
    Which way it went
    No clear difference
    Likely range
    Not in the abstract
    Source’s own words
    weighted mean difference in fasting plasma glucose vs comparison (no pooled estimate reported for the null result)
    Who was studied
    Patients with metabolic syndrome and related disorders
    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 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
    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

  • None gives a number at all, only which way it went.
  • Two give no likely range, so how precise those numbers are is unknown.
  • 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 Quercetin

Seven of the 19 things on our list for Quercetin have no reading here yet:

  • Common cold incidence
  • Endurance Performance (Time to Exhaustion)
  • Fasting insulin
  • HDL cholesterol
  • Interleukin-6
  • Oxidative stress (F2-isoprostanes)
  • Uric acid

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.