Fiber

How long does fiber take to lower cholesterol?

Updated 4 Nov 2026

Short answer

Trials measured the fall after about 3 to 12 weeks. Reviews included trials of at least 3 weeks, and barley beta-glucan lowered LDL cholesterol after a median of 4 weeks.[1][2] Oat beta-glucan lowered it by about 5% in 4 weeks.[3] With psyllium, LDL fell by 8.7% to 9.7% after 12 weeks, and by 10.6% to 13.2% over 6 months together with a change in diet.[4]

Longer use has little evidence behind it, because few trials lasted more than 12 weeks.[5] A 1999 review found that the effect did not depend on the length of treatment.[6]

Sources (6)

  1. Effect of psyllium (Plantago ovata) fiber on LDL cholesterol and alternative lipid targets, non-HDL cholesterol and apolipoprotein B: a systematic review and meta-analysis of randomized controlled trials. Jovanovski E, Yashpal S, Komishon A, Zurbau A, Blanco Mejia S, Ho HVT, et al. Am J Clin Nutr, 2018. PMID 30239559
  2. A systematic review and meta-analysis of randomized controlled trials of the effect of barley β-glucan on LDL-C, non-HDL-C and apoB for cardiovascular disease risk reduction(i-iv). Ho HV, Sievenpiper JL, Zurbau A, Blanco Mejia S, Jovanovski E, Au-Yeung F, et al. Eur J Clin Nutr, 2016. PMID 27273067
  3. Physicochemical properties of oat β-glucan influence its ability to reduce serum LDL cholesterol in humans: a randomized clinical trial. Wolever TM, Tosh SM, Gibbs AL, Brand-Miller J, Duncan AM, Hart V, et al. Am J Clin Nutr, 2010. PMID 20660224
  4. Ispaghula husk in the treatment of hypercholesterolaemia: a double-blind controlled study. MacMahon M, Carless J J Cardiovasc Risk, 1998. PMID 10201553
  5. Dietary fibre for the primary prevention of cardiovascular disease. Hartley L, May MD, Loveman E, Colquitt JL, Rees K Cochrane Database Syst Rev, 2016. PMID 26758499
  6. Cholesterol-lowering effects of dietary fiber: a meta-analysis. Brown L, Rosner B, Willett WW, Sacks FM Am J Clin Nutr, 1999. PMID 9925120

More about fiber

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For education; not medical advice. Talk to a doctor before you start, stop or change a supplement.