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Ole7.0
Olive Leaf Extract Research
Likely helps
76 peer-reviewed studies
What the evidence says
Too few graded studies
Olive Leaf Extract doesn't have enough studies with structured effect-size data yet to pool a verdict. Browse the studies below for individual findings.
Most evidence is from high-quality meta-analyses and randomised trials published 1991–2026 with a typical study size of 62 participants.
Based on 76 studies · 4 meta-analyses · 44 RCTs · 3,918 total participants
Confidence
High confidence
By outcome
Heart & blood pressureModest blood pressure reduction; lipid effects are mixed and inconsistent · 4-8 weeks
Too few graded studies60 studies
InflammationA meta-analysis found an inflammatory benefit in only 2 trials, and an RCT in people with high blood pressure found no change in inflammatory markers · 8 weeks
Too few graded studies18 studies
Glucose & metabolic
Too few graded studies11 studies
Cholesterol & lipidsModest blood pressure reduction; lipid effects are mixed and inconsistent · 4-8 weeks
Too few graded studies7 studies
Weight management
Too few graded studies7 studies
Immune supportIn 32 high-school athletes, no fewer respiratory infections but shorter ones. Antimicrobial activity is laboratory data · 2-4 weeks
Too few graded studies5 studies
Women's healthOne 60-woman RCT found improved overall menopause-specific quality of life scores. Effects on hot flashes and mood were not reported separately. · 4-8 weeks
Too few graded studies4 studies
Safety profile
Too few graded studies3 studies
Cold sores & HSV
Too few graded studies2 studies
Therapeutic & clinical
Too few graded studies2 studies
Joint pain & arthritis
Too few graded studies1 study
Liver health
Too few graded studies1 study
Digestive health
Too few graded studies1 study
By the numbers
Pulled from 29 studies with measurable effects
Likely real effects
100%
across studies
People studied
3,918
typical study: 62 people
Strongest designs
48
4 pooled, 44 randomised
How long studies ran
Under a week
1
1–3 months
2
Populations Studied
Hypertensive patients2
General population2
Patients with herpes labialis1
Individuals assessed for cardiometabolic risk factors1
Active research area
45 studies in the last 5 years · Latest meta-analysis: 2026
199120082026
1Herpes labialis symptomsSystematic ReviewCited 2×n=1,250 · large study2025
In plain English: Future well-designed, large-scale RCTs employing standardized methodologies are necessary to confirm these findings and to establish optimal treatment protocols for diverse patient populations (Inplasy protocol number: 202350038).
Anheyer M et al. · Journal of integrative and complementary medicine (2025)
Lemon balm preparations consistently reduced pain intensity and swelling, with some studies also reporting a significant decrease in lesion size compared with placebo or acyclovir.
Olive leaf extract demonstrated a statistically significant faster improvement in symptoms and a shorter healing time compared with acyclovir.
Discussion: The findings indicate that topical herbal therapies may provide effective and well-tolerated alternatives or adjuncts to conventional antiviral treatments for herpes labialis.
In plain English: Overall, the meta-analysis suggests that supplementation with OLE, HT, and TYR may beneficially impact some cardiometabolic parameters, though further studies are needed to confirm these findings.
Frumuzachi O et al. · Critical reviews in food science and nutrition (2025)
Fourteen human intervention studies with 594 participants were included.
Subgroup analysis showed that, in certain contexts, interventions may be more beneficial for BMI <30, non-Mediterranean, and cardiometabolic disease individuals, while intervention compound, type of intervention, and duration might have differential effects regarding considered outcomes.
Overall, the meta-analysis suggests that supplementation with OLE, HT, and TYR may beneficially impact some cardiometabolic parameters, though further studies are needed to confirm these findings.
3Fasting glycemiaMeta-AnalysisCited 7×n=703 · large study2024
In plain English: In the meta-analysis, fasting glycemia, as evaluated in studies using a low dose of OLE, showed a significant result favoring the control group.
Álvares AA et al. · Nutrition reviews (2024)
Systematic review and meta-analysis of 12 RCTs of pure olive leaf extract in 703 adults, lasting 2 days to 12 weeks.
Individual trials reported benefits for glucose metabolism (4 RCTs), blood pressure (2), lipids (2) and inflammatory markers (2).
In the pooled analysis, fasting glucose in the low-dose studies favoured the control group, not the extract.
In plain English: This review is the first to provide a compiled list of traditional medicinal plants used worldwide against diabetes.
Aumeeruddy MZ et al. · Current medicinal chemistry (2021)
2004 traditionally used plants belonging to 1112 genera and 197 families were reported across 92 countries for the management of diabetes. Olea europaea L. was among the species mostly reported.
This review is the first to provide a compiled list of traditional medicinal plants used worldwide against diabetes. It records traditional use, not clinical efficacy.
In plain English: We conclude that EVOO and its OOPCs can regulate gene expression by modifying epigenetic mechanisms that impact human pathophysiology.
Del Saz-Lara A et al. · Advances in nutrition (Bethesda, Md.) (2022)
We conclude that EVOO and its OOPCs can regulate gene expression by modifying epigenetic mechanisms that impact human pathophysiology.
A full elucidation of the epigenetic effects of EVOO and its OOPCs may contribute to developing different pharma-nutritional strategies that exploit them as epigenetic agents.
In plain English: Further investigations are necessary to clarify the real chemopreventive potential of olive oil secoiridoid phenols on humans performing intervention studies on populations at high cancer risk.
Fabiani R · Food & function (2016)
All human intervention trials have investigated the effects of olive oil phenols on DNA damage.
Among the five selected studies, three have shown a significant preventive effect on oxidative DNA damage in terms of reduction of 8-oxo-7,8-dihydro-2'-deoxyguanosine in urine, in mitochondria DNA of mononuclear cells and in lymphocyte DNA.
The other two studies failed to see an effect on the urinary excretion of either etheno-DNA adducts or oxidation products of guanine.
In plain English: Current evidence supports the Mediterranean diet as a promising dietary strategy to slow the progression of neurodegenerative diseases.
Fekete M, Jarecsny T, Lehoczki A, Major D, Fazekas-Pongor V, Csípő T, Lipécz Á, Szappanos Á, Pázmándi EM, Varga P, Varga JT. · Nutrients (2025)
Clinical studies, although limited, indicate beneficial effects of polyphenol-rich interventions on cognitive and metabolic biomarkers.
Conclusions: Current evidence supports the Mediterranean diet as a promising dietary strategy to slow the progression of neurodegenerative diseases.
Polyphenols, including resveratrol and oleuropein, may play a role in mediating these effects.
In plain English: Special attention is given to their mechanistic actions and therapeutic potential in the context of iron-related disorders.
Freitas SML et al. · Critical reviews in food science and nutrition (2026)
Emerging evidence suggests that these compounds influence the expression and activity of iron-regulatory proteins such as hepcidin, ferroportin (FPN), ferritin, transferrin, and divalent metal transporter 1 (DMT1).
Their biological effects are frequently attributed to antioxidant, metal-chelating, and anti-inflammatory properties.
This review provides a comprehensive overview of selected plant-derived bioactive compounds-curcumin, catechins, quercetin, resveratrol, sulforaphane, tannins, myricetin, apigenin, and oleuropein-and their roles in iron metabolism and homeostasis.
1224-hour systolic blood pressureRCTCited 1×n=621 · large study2025
In plain English: OLE can decrease 24-h BP, BPL, and diastolic BPV with improvement of lipid profile, systemic inflammation, and body weight in hypertensive patients.
Lamti F et al. · Journal of hypertension (2025)
OLE significantly reduced 24-h SBP compared to baseline and placebo group [respectively -6.4 mmHg (95% confidence interval, 95% CI -10 to -2.1) and -1.5 mmHg (95% CI -3.9 to 0.51); P < 0.01].
In OLE group, systolic BPL decreased from 53.9% at baseline to 42.2% at 12-week ( P = 0.03); in placebo group, it did not change significantly ( P = 0.55).
Diastolic BPL decreased from 30.7 to 21.2% ( P = 0.03) in OLE group and did not change significantly in placebo group ( P = 0.12).
18Blood pressureCrossoverCited 17×n=37 · small study2014
In plain English: Further dose-response evaluation of olive leaf, green coffee bean or beetroot extracts is required to confirm or refute the purported benefits.
Wong RH et al. · Nutrients (2014)
Adults with high normal or borderline elevated blood pressure took a combination of 500 mg olive leaf extract, 100 mg green coffee bean extract and 150 mg beet powder, or placebo, twice daily for six weeks each.
Baseline clinic BP in 37 overweight middle-aged men and women who completed the trial averaged 145/84 mmHg.
There was no significant effect of treatment on ABP or any other outcome measure.
19LDL cholesterol reductionRCTCited 7×n=105 · medium study2023
In plain English: Our results confirm the LDL-C-lowering properties of monacolin are clinically meaningful even in lower doses of 3 mg/day.
Angelopoulos N et al. · Nutrients (2023)
105 people with mild hypercholesterolemia were randomised to lifestyle modification alone or with a supplement combining monacolin K (3 mg or 10 mg) with coenzyme Q10, grape seed and olive leaf extracts, for 8 weeks. The effect cannot be credited to olive leaf extract, and the authors attribute it to monacolin.
LDL-C decreased by 26.46% on average (p < 0.001) during treatment with 10 mg of monacolin and by 16.77% on average during treatment with 3 mg of monacolin (p < 0.001).
Triglycerides fell slightly only in the high-dose group (mean -4.25%). The authors call this significant, although the reported 95% CI (-11.11 to 2.61) includes zero.