Herb ·Emerging evidence ·Reviewed May 2026
Rich in oleuropein with antimicrobial, antioxidant, and cardiovascular benefits.
The bottom line
Evidence rating emerging. Most-documented uses: immune support, blood pressure, antioxidant. 19 sources indexed (2010–2026), with 5 interaction records on file.
Core mechanism
Oleuropein and hydroxytyrosol inhibit bacterial, viral, and fungal growth. Modulate eNOS for blood pressure support. Potent antioxidant via radical scavenging and metal chelation.17,3
Dosing protocol
Oleuropein content drives effect; check standardization.
Ranked by evidence and value.
Real-world pricing across three quality tiers. Assumes Oleuropein-Standardized Olive Leaf.
Assumes 500-1,000 mg/day. Vendor basis: NOW/iHerb, Vitacost, Life Extension, and Amazon marketplace; 18-20% oleuropein extracts set the mid tier. Updated 2026-05-28.
How much you'd eat to match a supplemental dose.
Leaf extract is much more concentrated in oleuropein than common olive foods.
What to test, the optimal window inside the conventional range, and how long a response takes.
Olive leaf extract (500 to 1000 mg per day, standardized to 16 to 24 percent oleuropein) lowers SBP by roughly 5 to 11 mmHg in hypertensives in small RCTs.14,1
Pair with LDL since olive leaf also modestly lowers cholesterol. Oleuropein content drives effect; check standardization.
Olive leaf extract is expected to modestly lower diastolic blood pressure, with effects that are typically small, dose-dependent, and clearest when a baseline elevation (pre-hypertension or stage 1 hypertension) is present.4,14
Measure after 5 minutes seated rest, feet flat, arm supported at heart level, no caffeine, exercise, or smoking in the prior 30 minutes. Use the average of 2 to 3 readings on the same arm and track at the same time of day. Home readings across several days are more reliable than a single clinic measurement.
Olive leaf extract is expected to modestly lower fasting glucose, with effects that are typically small, dose-dependent, and clearest when baseline glucose is elevated.1,2
Requires an 8 hour fast. Recent illness, poor sleep, stress, and acute carbohydrate intake can transiently raise readings, so test under consistent morning conditions. Pair with HbA1c for a longer-term view.
Where this appears in the symptom-to-supplement map, ranked by relevance.
Oleuropein has shown antimicrobial and antifungal effects in vitro, providing a plausible but largely untested rationale for candida support.3,5
Human evidence is minimal; treat as a complementary option rather than a primary therapy.
Olive leaf polyphenols such as oleuropein have antimicrobial and immune-modulating activity in laboratory and early human studies.11,13
Human evidence is preliminary and mostly mechanistic; treat as adjunctive only and discuss with a clinician if you take blood pressure medication.
Olive leaf extract has Captopril-comparable blood pressure lowering effects (500mg BID). Oleuropein is a CYP3A4 mechanism-based inhibitor.
Recommendation: Monitor blood pressure closely. May need medication dose adjustment.
Both olive leaf extract and berberine can lower blood glucose and blood pressure, so combining them may produce additive hypoglycemic and hypotensive effects.
Recommendation: Monitor blood glucose and blood pressure when combining, especially alongside antidiabetic or antihypertensive medication, and adjust as needed.
Olive leaf extract and garlic extract both modestly lower blood pressure, so combined use may produce additive hypotensive effects.
Recommendation: Monitor blood pressure when used together, particularly in those already on antihypertensive therapy, and watch for symptoms of low blood pressure.
Olive leaf polyphenols and quercetin are complementary antioxidant and anti-inflammatory flavonoids that may also additively support healthy blood pressure and endothelial function.
Recommendation: Reasonable to combine for antioxidant and vascular support; monitor blood pressure if also taking antihypertensives.
Olive Leaf Extract lowers blood pressure (about 4-11 mm Hg systolic depending on dose) and was non-inferior to captopril for stage 1 hypertension in one randomized trial. Combined with lisinopril the effects are additive and generally well tolerated, though mild hypotension is possible if blood pressure is already at goal.
Recommendation: Olive Leaf Extract 500-1000 mg/day is a typical research dose. Monitor home blood pressure after starting and tell your prescriber so your lisinopril dose can be reviewed.
Numbered references. Citations throughout the page link here.
Systematic review and meta-analysis of 12 RCTs (703 patients) found OLE showed positive correlations with glucose metabolism (4 RCTs), blood pressure (2 RCTs), lipid profile (2 RCTs), and inflammatory markers (2 RCTs).
Reductions in total cholesterol, LDL cholesterol, triglycerides, and interleukin-8 observed with olive leaf extract compared to control.
Menezes RCR, Peres KK, Costa-Valle MT et al.. Oral administration of oleuropein and olive leaf extract has cardioprotective effects in rodents: A systematic review. Revista portuguesa de cardiologia : orgao oficial da Sociedade Portuguesa de Cardiologia = Portuguese journal of cardiology : an official journal of the Portuguese Society of Cardiology. 2022
Five trials (325 patients) showed olive leaf extract decreased 24-hour BP, BP load, and diastolic BP variability with improvements in lipid profile and inflammation.
Fladerer-Grollitsch JP, Bucar F, Klein T et al.. 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. 2026
Forbes-Hernández TY, Vargas-Corral FG, Bullón B et al.. Adjuvant treatment with an oleuropein-enriched olive leaf extract improves periodontal outcomes in older adults with periodontitis: Metabolomic insights from a randomized controlled trial. Phytomedicine : international journal of phytotherapy and phytopharmacology. 2026
RCT of 70 obese women found OLE (250 mg/day) combined with a hypocaloric diet for 8 weeks significantly reduced serum malondialdehyde compared to placebo + hypocaloric diet.
RCT of 100 elderly patients with knee osteoarthritis found OLE (oral and/or topical) significantly reduced pain scores and improved daily functioning. Combination of oral and topical showed the most pronounced effects.
Lasfar A, van Stratum SLM, Imperatrice M et al.. 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. 2025
Gaizeh Al-Hallak MA, Hsaian JA, Aljoujou AA. Evaluating the effectiveness of topical olive leaf extract emulgel in managing recurrent herpes labialis: a randomized controlled clinical study. Scientific reports. 2024
Olive leaf extract supplementation demonstrated effects on cardiovascular health markers in a placebo-controlled trial.
Olive leaf extract supplementation produced a significant 28% reduction in sick days in high school athletes, though illness incidence was not significantly different.
In pre-hypertensive males, 136 mg oleuropein daily significantly lowered daytime and 24-hour systolic and diastolic blood pressure.
At 62.5 mg/ml concentration, olive leaf extract almost completely inhibited growth of Listeria monocytogenes, E. coli O157:H7, and Salmonella Enteritidis.
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