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Grape Seed Extract Side Effects & Safety

Evidence:Moderate
·

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, stomach upset)
  • Headache (usually transient)
  • Dizziness at higher doses
  • Allergic reaction in grape-sensitive individuals (rare)

Drug & Supplement Interactions

  • Anticoagulants/antiplatelets — OPCs may have mild antiplatelet effects; use with caution
  • Antihypertensive drugs — additive blood pressure lowering; monitor BP
  • Iron supplements — tannins in GSE may reduce iron absorption; take separately

Maximum Dose

Do not exceed: 600mg/day (well-tolerated in clinical trials)

Full Grape Seed Extract Guide

References

  1. Meta-analysisZhang H, Liu S, Li L, Liu S, Liu S, Mi J, Tian G (2016). The impact of grape seed extract treatment on blood pressure changes: A meta-analysis of 16 randomized controlled trials. Medicine. DOI PubMed
  2. Meta-analysisFeringa HH, Laskey DA, Dickson JE, Coleman CI (2011). The effect of grape seed extract on cardiovascular risk markers: a meta-analysis of randomized controlled trials. Journal of the American Dietetic Association. DOI PubMed
  3. Meta-analysisFoshati S, Rouhani MH, Amani R (2021). The effect of grape seed extract supplementation on oxidative stress and inflammation: A systematic review and meta-analysis of controlled trials.. International journal of clinical practice. DOI PubMed
  4. Meta-analysisAsbaghi O, Nazarian B, Reiner Ž, Amirani E, et al. (2020). The effects of grape seed extract on glycemic control, serum lipoproteins, inflammation, and body weight: A systematic review and meta-analysis of randomized controlled trials.. Phytotherapy research : PTR. DOI PubMed
  5. ReviewGrohmann T, Litts C, Horgan G, Zhang X, et al. (2021). Efficacy of Bilberry and Grape Seed Extract Supplement Interventions to Improve Glucose and Cholesterol Metabolism and Blood Pressure in Different Populations-A Systematic Review of the Literature.. Nutrients. DOI PubMed
  6. ReviewDelimont NM, Carlson BN (2020). Prevention of dental caries by grape seed extract supplementation: A systematic review.. Nutrition and health. DOI PubMed
  7. ReviewOlaku OO, Ojukwu MO, Zia FZ, White JD (2015). The Role of Grape Seed Extract in the Treatment of Chemo/Radiotherapy Induced Toxicity: A Systematic Review of Preclinical Studies.. Nutrition and cancer. DOI PubMed
Show 5 more references
  1. Chen B, Li Y, Li Z, Hu X, et al. (2025). Vitamin E ameliorates blood cholesterol level and alters gut microbiota composition: A randomized controlled trial.. Nutrition, metabolism, and cardiovascular diseases : NMCD. DOI PubMed
  2. RCTLira A, Boyer W, Gillum T, Sullivan S, et al. (2025). Effect of 7-day dietary supplementation with grape seed extract on cardiac autonomic and hemodynamic responses in elevated and stage 1 hypertension.. Clinical physiology and functional imaging. DOI PubMed
  3. RCTEshaghian N, Sadeghi O, Foroghi A, Khorvash F, et al. (2025). Effects of grape seed extract supplementation on inflammatory biomarkers, oxidative stress, clinical symptoms, and quality of life in patients with migraine: A double-blinded randomized placebo-controlled clinical trial.. Journal of research in medical sciences : the official journal of Isfahan University of Medical Sciences. DOI PubMed
  4. Meta-analysisAbdulla SA, Abdalla BA, Muhammed AA, Elawamy HA, et al. (2025). The Impact of Antioxidant Adjuncts on Periodontal Health in Type 2 Diabetes Patients: A Meta-Analysis.. Clinical and experimental dental research. DOI PubMed
  5. RCTGhanbari P, Raiesi D, Alboebadi R, Zarejavid A, et al. (2024). The effects of grape seed extract supplementation on cardiovascular risk factors, liver enzymes and hepatic steatosis in patients with non-alcoholic fatty liver disease: a randomised, double-blind, placebo-controlled study.. BMC complementary medicine and therapies. DOI PubMed