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Open WellbeingWhat the studies actually measured

Cholesterol and blood fats

Piperineand LDL cholesterol

Three sources here, and they say different things: one measured lower LDL cholesterol and two found no clear difference.

How sure anyone can be

Low certainty, level 2 of 4

Further research is likely to change this.

The most certain of the three 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.

-7.22-2.22.8

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

Three 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, 2026 · 16 studies pooled

    Low certainty, level 2 of 4

    Effects of Curcuminoids Plus Piperine Co-Supplementation on Serum Lipid Profile in Adults: A Systematic Review and Meta-Analysis of RCTs.

    Lipids. 2026;61(1):91-107. doi:10.1002/lipd.70004. PMID:41057035.

    Number reported
    -2.2
    Which way it went
    No clear difference
    Likely range
    -7.22 to 2.8
    Source’s own words
    LDL cholesterol weighted mean difference vs control, printed as mg/mL in the abstract (almost certainly a typesetting error for mg/dL)
    Who was studied
    Adult
    Compared with
    control
    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 16 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

  • Systematic review, 2023

    Low certainty, level 2 of 4

    A systematic review and meta-analysis of randomized controlled trials investigating the effect of the curcumin and piperine combination on lipid profile in patients with metabolic syndrome and related disorders.

    Phytother Res. 2023;37(3):1212-1224. doi:10.1002/ptr.7730. PMID:36649934.

    Number reported
    Not in the abstract
    Which way it went
    Lower
    Likely range
    Not in the abstract
    Source’s own words
    no effect size is reportable: the abstract states the pooled direction without a magnitude, interval, trial count or participant total
    Who was studied
    Adult with metabolic syndrome
    Compared with
    control (comparator not detailed 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.

    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, 2023 · 66 participants

    Low certainty, level 2 of 4

    The effects of curcumin-piperine supplementation on inflammatory, oxidative stress and metabolic indices in patients with ischemic stroke in the rehabilitation phase: a randomized controlled trial.

    Nutr J. 2023;22(1):69. doi:10.1186/s12937-023-00905-1. PMID:38082237.

    Number reported
    Not in the abstract
    Which way it went
    No clear difference
    Likely range
    Not in the abstract
    Source’s own words
    no effect size is reported: the abstract gives only a p value for the between-group comparison, with no magnitude or interval
    Who was studied
    Adult with ischemic stroke in rehabilitation
    Compared with
    placebo
    Amount taken
    5 mg/day piperine (with 500 mg/day curcumin)
    For how long
    84 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 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

  • Two give no 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 — Two of Three readings: Not in the abstract.
  • For how long — Two of Three readings: Not in the abstract.

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

Still to read for Piperine

Five of the 17 things on our list for Piperine have no reading here yet:

  • Atrial fibrillation incidence
  • Carotid intima-media thickness (CIMT)
  • Fibrinogen
  • Oxidative stress (F2-isoprostanes)
  • 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.