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Olive Leaf Extract Side Effects & Safety

Evidence:Emerging
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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

  • Generally well-tolerated
  • Mild GI symptoms (nausea, acid reflux) in some individuals
  • Herxheimer-like die-off reactions reported anecdotally when starting supplementation (headache, fatigue)
  • May lower blood pressure — beneficial for most but monitor if already on antihypertensives

Drug & Supplement Interactions

  • Antihypertensive medications — olive leaf extract may lower blood pressure; monitor for additive effects
  • Diabetes medications — may lower blood glucose; monitor levels
  • Blood thinners — theoretical antiplatelet effects; consult physician

Maximum Dose

Do not exceed: No established upper limit; doses up to 1500mg/day used without adverse effects in studies

Full Olive Leaf Extract Guide

References

  1. ReviewBarbaro B, Toietta G, Maggio R, et al. (2014). Effects of the olive-derived polyphenol oleuropein on human health. International Journal of Molecular Sciences. DOI PubMed
  2. ObservationalMicol V, Caturla N, Perez-Fons L, Mas V, Perez L, Estepa A (2005). The olive leaf extract exhibits antiviral activity against viral haemorrhagic septicaemia rhabdovirus (VHSV). Antiviral Research. DOI PubMed
  3. Meta-analysisÁlvares AA, Garcêz A, Silva LT, Averbuch N, et al. (2024). Olive leaf extract effect on cardiometabolic risk factors: a systematic review and meta-analysis of randomized clinical trials.. Nutrition reviews. DOI PubMed
  4. RCTFladerer-Grollitsch JP, Bucar F, Klein T, Kompek A, et al. (2026). Effects of a combination of olive leaf extract and potassium on blood pressure in participants with mild to moderate hypertension: A double blind, randomized, placebo-controlled trial.. Phytomedicine : international journal of phytotherapy and phytopharmacology. DOI PubMed
  5. Câmara Rocha Menezes R, Peres KK, da Mata IR, Morelo Dal Bosco S, et al. (2026). Metabolic and inflammatory effects of oleuropein and olive leaf extract: a systematic review and meta-analysis.. Food & function. DOI PubMed
  6. Lasfar A, van Stratum SLM, Imperatrice M, van Kalkeren CAJ, et al. (2025). Effects of olive leaf extract supplementation on systemic markers of tissue aging and remodeling in postmenopausal women: a randomized controlled trial with exploratory skin outcomes.. Frontiers in nutrition. DOI PubMed
  7. Pinckaers PJ, Petrick HL, Horstman AM, Moreno-Asso A, et al. (2025). Oleuropein Supplementation Increases Resting Skeletal Muscle Fractional Pyruvate Dehydrogenase Activity but Does Not Influence Whole-Body Metabolism: A Randomized, Double-Blind, and Placebo-Controlled Trial in Healthy, Older Males.. The Journal of nutrition. DOI PubMed
Show 4 more references
  1. Imperatrice M, Lasfar A, van Kalkeren CAJ, Troost F (2024). Olive Leaf Extract Supplementation Improves Postmenopausal Symptoms: A Randomized, Double-Blind, Placebo-Controlled Parallel Study on Postmenopausal Women.. Nutrients. DOI PubMed
  2. Angelopoulos N, Paparodis RD, Androulakis I, Boniakos A, et al. (2023). Low Dose Monacolin K Combined with Coenzyme Q10, Grape Seed, and Olive Leaf Extracts Lowers LDL Cholesterol in Patients with Mild Dyslipidemia: A Multicenter, Randomized Controlled Trial.. Nutrients. DOI PubMed
  3. Meta-analysisRazmpoosh E, Abdollahi S, Mousavirad M, Clark CCT, et al. (2022). The effects of olive leaf extract on cardiovascular risk factors in the general adult population: a systematic review and meta-analysis of randomized controlled trials.. Diabetology & metabolic syndrome. DOI PubMed
  4. Lemonakis N, Mougios V, Halabalaki M, Dagla I, et al. (2022). Effect of Supplementation with Olive Leaf Extract Enriched with Oleuropein on the Metabolome and Redox Status of Athletes' Blood and Urine-A Metabolomic Approach.. Metabolites. DOI PubMed