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Studies
Ole7.0
Olive Leaf Extract Research
Likely helps
103 peer-reviewed studies
What the evidence says
Likely helps
Olive Leaf Extract appears to help in 9 of 11 studies with measurable effects — the evidence leans clearly favourable.
Most evidence is from high-quality meta-analyses and randomised trials published 1991–2026 with a typical study size of 70 participants.
Based on 103 studies · 8 meta-analyses · 68 RCTs · 6,786 total participants
Confidence
High confidence
What the studies found
9helped1unclear1didn't help· 92 more without graded effect data
By outcome
Heart & blood pressureModest blood pressure reduction; lipid effects are mixed and inconsistent · 4-8 weeks
Cholesterol & lipidsModest blood pressure reduction; lipid effects are mixed and inconsistent · 4-8 weeks
Likely helps9 studies
Immune supportEnhanced immune function and antimicrobial activity · 2-4 weeks
Mostly mechanism / observational8 studies
Weight management
Mostly mechanism / observational7 studies
Women's healthMay help manage menopausal symptoms like hot flashes and mood changes · 4-8 weeks
Mostly mechanism / observational5 studies
Cold sores & HSV
Too few graded studies2 studies
Joint pain & arthritis
Too few graded studies2 studies
Digestive health
Too few graded studies2 studies
Safety profile
Too few graded studies2 studies
Liver health
Too few graded studies1 study
Therapeutic & clinical
Too few graded studies1 study
By the numbers
Pulled from 42 studies with measurable effects
Likely real effects
50%
across studies
People studied
6,786
typical study: 70 people
Strongest designs
76
8 pooled, 68 randomised
Showed benefit
82%
9/11 studies
How long studies ran
Under a week
1
1–3 months
4
Populations Studied
General population4
Hypertensive patients2
Patients with herpes labialis1
Individuals assessed for cardiometabolic risk factors1
Active research area
58 studies in the last 5 years · Latest meta-analysis: 2026
199120082026
1Herpes labialis healing time and symptom reductionSystematic ReviewCited 2×n=1,250 · large study2025
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.
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.
Despite these results, further multicenter clinical studies with a wider range of patients are required to confirm and better understand EVOO's effects on the prevention of cardiovascular risk.
Ussia S et al. · Nutrients (2025)
The beneficial effect was attributed to the polyphenols contained in EVOO.
Indeed, EVOO supplementation as part of the Mediterranean diet could improve patients' quality of life in secondary prevention by demonstrating a positive correlation with the cardioprotective role of polyphenols.
Discussion: A balanced diet with VOO represents a simple yet potent method to counteract metabolic dysfunctions associated with CVD.
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.
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.
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.
Further well-designed, long-term clinical trials are needed to establish causal relationships, optimize dosage, and explore biomarker-driven personalized nutrition approaches.
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.