We use essential cookies (authentication, your saved goals/stack) by default. With your permission we'll also enable privacy-respecting analytics (Vercel Web Analytics, anonymous load-time metrics) and error-replay diagnostics (Sentry — DOM snapshots only when an error fires) so we can fix bugs faster. Learn more about cookies
Flx5.0
Flaxseed Research
Mostly mechanism / observationalHigh safety
5 peer-reviewed studies
What the evidence says
Mostly mechanism / observational
Most Flaxseed studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from high-quality meta-analyses and randomised trials published 2012–2022 with a typical study size of 110 participants.
Based on 5 studies · 3 meta-analyses · 2 RCTs · 1,502 total participants
Confidence
High
By outcome
Heart & blood pressureRoughly 2-3 mmHg lower systolic/diastolic blood pressure and modest LDL reduction with whole/milled flaxseed · 8-12 weeks
Too few graded studies2 studies
Women's healthWeak, inconsistent effect on climacteric symptoms via lignan phytoestrogens · Up to 6 months
Too few graded studies2 studies
Glucose & metabolicSmall reductions in fasting glucose and insulin resistance (whole flaxseed only; no HbA1c change) · 12 weeks
Too few graded studies1 study
Steady research
1 study in the last 5 years · Latest meta-analysis: 2022
201220172022
1Meta-Analysisn=1,302 · large study2016
Meta-analysis of 15 RCTs found significant reductions in systolic (-2.85 mmHg) and diastolic (-2.39 mmHg) blood pressure with flaxseed, with larger effects for trials lasting 12 weeks or more and for flaxseed powder rather than lignan extract.
Ursoniu S, Sahebkar A, Andrica F, Serban C, Banach M; LBPMC Group · Clin Nutr (2016)
15 trials (19 treatment arms), 1302 participants
Systolic BP reduced by -2.85 mmHg (95% CI -5.37 to -0.33, p=0.027)
Diastolic BP reduced by -2.39 mmHg (95% CI -3.78 to -0.99, p=0.001)
In peripheral artery disease patients, 30g/day of milled flaxseed lowered systolic BP by ~10 mmHg and diastolic BP by ~7 mmHg versus placebo over 6 months, with the largest effect in those who started hypertensive.
Across 25 RCTs, flaxseed modestly reduced fasting glucose, insulin, and HOMA-IR — but only whole flaxseed (not oil or lignan extract) helped, and there was no effect on HbA1c.
Mohammadi-Sartang M, Sohrabi Z, Barati-Boldaji R, Raeisi-Dehkordi H, Mazloom Z · Nutr Rev (2018)
25 RCTs (30 treatment arms)
Fasting glucose reduced by -2.94 mg/dL (95% CI -5.31 to -0.56, p=0.015)
Insulin and HOMA-IR significantly reduced; insulin sensitivity (QUICKI) increased
In postmenopausal women, flaxseed intake significantly lowered total cholesterol, LDL, and HDL cholesterol, suggesting a favorable effect on the lipid profile.
Błaszczuk A, Barańska A, Kanadys W, et al. · Nutrients (2022)
Systematic review and meta-analysis in postmenopausal women
Total cholesterol reduced (WMD -0.26 mmol/L, p=0.0001)
Flaxseed meal and extract showed a trend toward reduced Kupperman menopausal symptom scores, but ANOVA found no significant between-group difference, so the menopausal benefit remains uncertain.
Colli MC, Bracht A, Soares AA, et al. · J Med Food (2012)
90 menopausal women randomized to flaxseed extract, flaxseed meal, or placebo, 6 months
Paired t-tests showed symptom reduction within flaxseed groups (p<0.01)
ANOVA of change scores found no significant between-group difference (p=0.084)