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Beta-Sitosterol Side Effects & Safety

Evidence:Moderate
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This content is for informational purposes only and does not constitute medical advice. Statements about dietary supplements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease. Individual results may vary — consult your healthcare provider before starting any supplement. Full disclaimer

Safety Profile

Overall safety rating: Generally Safe

Potential Side Effects

  • Mild GI discomfort (nausea, bloating, diarrhea) at higher doses
  • May reduce absorption of fat-soluble vitamins (A, D, E, K) at very high doses
  • Rare: erectile dysfunction reported in isolated cases at high doses
  • Contraindicated in sitosterolemia (rare genetic condition)

Drug & Supplement Interactions

  • May reduce absorption of ezetimibe and other cholesterol-lowering drugs
  • Separate from fat-soluble vitamins by 2 hours at high doses
  • Potential additive effect with statin medications on cholesterol
  • May reduce absorption of carotenoids (beta-carotene, lycopene)

Maximum Dose

Do not exceed: 2g daily (plant sterol blend); no established UL for isolated beta-sitosterol

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References

  1. RCTBerges RR, Windeler J, Trampisch HJ, Senge T (1995). Randomised, placebo-controlled, double-blind clinical trial of beta-sitosterol in patients with benign prostatic hyperplasia. The Lancet. DOI PubMed
  2. ReviewWilt TJ, MacDonald R, Ishani A (1999). Beta-sitosterol for the treatment of benign prostatic hyperplasia: a systematic review. BJU International. DOI PubMed
  3. RCTKlippel KF, Hiltl DM, Schipp B (1997). A multicentric, placebo-controlled, double-blind clinical trial of beta-sitosterol for benign prostatic hyperplasia. British Journal of Urology. DOI PubMed
  4. Meta-analysisAbumweis SS, Barake R, Jones PJH (2008). Plant sterols/stanols as cholesterol lowering agents: a meta-analysis of randomized controlled trials. Food & Nutrition Research. DOI PubMed
  5. ReviewUlbricht CE (2016). An Evidence-Based Systematic Review of Beta-Sitosterol, Sitosterol (22,23- dihydrostigmasterol, 24-ethylcholesterol) by the Natural Standard Research Collaboration.. Journal of dietary supplements. PubMed
  6. Ontawong A, Pengnet S, Thim-Uam A, Munkong N, et al. (2024). A randomized controlled clinical trial examining the effects of Cordyceps militaris beverage on the immune response in healthy adults.. Scientific reports. DOI PubMed
  7. Meng H, Matthan NR, Angellotti E, Pittas AG, et al. (2020). Exploring the effect of vitamin D3 supplementation on surrogate biomarkers of cholesterol absorption and endogenous synthesis in patients with type 2 diabetes-randomized controlled trial.. The American journal of clinical nutrition. DOI PubMed
Show 1 more reference
  1. Ho XL, Loke WM (2017). Dietary Plant Sterols Supplementation Increases In Vivo Nitrite and Nitrate Production in Healthy Adults: A Randomized, Controlled Study.. Journal of food science. DOI PubMed