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Ole8.5
Olive Leaf Extract Research
Likely helpsHigh safety
44 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 2009–2026 with a typical study size of 74 participants.
Based on 44 studies · 5 meta-analyses · 27 RCTs · 6,197 total participants
Confidence
High
What the studies found
9helped1unclear1didn't help· 33 more without graded effect data
Immune supportEnhanced immune function and antimicrobial activity · 2-4 weeks
Mostly mechanism / observational5 studies
Weight management
Mostly mechanism / observational5 studies
Women's healthMay help manage menopausal symptoms like hot flashes and mood changes · 4-8 weeks
Too few graded studies2 studies
Cold sores & HSV
Too few graded studies1 study
Joint pain & arthritis
Too few graded studies1 study
Liver health
Too few graded studies1 study
Digestive health
Too few graded studies1 study
Therapeutic & clinical
Too few graded studies1 study
Safety profile
Too few graded studies1 study
By the numbers
Pulled from 37 studies with measurable effects
Likely real effects
50%
across studies
People studied
6,197
typical study: 74 people
Strongest designs
32
5 pooled, 27 randomised
Showed benefit
82%
9/11 studies
How long studies ran
Under a week
1
1–3 months
4
Populations Studied
General population5
Hypertensive patients2
Patients with herpes labialis1
Individuals assessed for cardiometabolic risk factors1
Active research area
26 studies in the last 5 years · Latest meta-analysis: 2026
200920172026
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 (2025)
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
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)
Noticeable benefit
← WorseNo effectBetter →
Likely real
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).
14LDL cholesterol reductionRCTCited 6×n=105 · medium study2023
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)
Large benefit
← WorseNo effectBetter →
Likely real
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).
We observed a slight but significant reduction of the triglyceride levels only in the high-dose-treated group (mean -4.25%; 95% CI of mean -11.11 to 2.61).
No severe adverse events occurred during the study.
15Blood pressureCrossoverCited 15×n=500 · large study2014
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)
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.
The failure to confirm prior evidence of the antihypertensive benefits of these extracts emphasises the importance of placebo control and the value of ABP monitoring.
16Postmenopausal symptoms (MENQoL score)RCTCited 5×n=60 · small study2024
Further studies are needed to elucidate the mechanisms underlying the observed effects.
Imperatrice M et al. · Nutrients (2024)
No clear effect
← WorseNo effectBetter →
Likely real
After six and twelve weeks of OLE supplementation, the overall MENQoL score significantly improved (estimated mean difference [95% CI]: -0.2 [-0.4-0.2], p = 0.027) compared to the placebo.
A significant improvement (+0.017 [0.003, 0.030], p = 0.019) was recorded in the BMD in the right arm in the OLE group compared to the placebo.
TG concentrations and the TG/HDL-C ratio were significantly decreased (-0.1 [-0.2, 0.0], p = 0.010; -0.1 [-0.2, -0.0], p = 0.029, respectively) in the OLE group compared to the placebo.
17Skeletal muscle fractional PDH activityRCTCited 6×n=40 · small study2025
Chronic OLE supplementation resulted in higher skeletal muscle fractional PDH activity in healthy, older males, which may impact resting energy metabolism.
Pinckaers PJ et al. · The Journal of nutrition (2025)
Large benefit
← WorseNo effectBetter →
Likely real
Ribonucleic acid sequencing revealed upregulation of oxidative phosphorylation gene pathways (false discovery rate < 0.05), whereas PDH-Serine293-phosphorylation was higher after acute OLE compared with PLA ingestion (P = 0.015).
Following chronic supplementation, fractional PDH activity was ∼25% greater in OLE compared with PLA (49 ± 14 compared with 38 ± 10%; P = 0.016) with no differences in absolute PDH activity and PDH-Serine293-phosphorylation between groups.
Plasma low-density lipoprotein cholesterol was lower after chronic OLE compared with PLA (P = 0.043), with no differences in other blood metabolic markers.
20Pain reduction in knee osteoarthritisRCTCited 3×2025
Hydroalcoholic olive leaf extract effectively reduces pain and improves physical functioning in elderly patients with knee osteoarthritis, offering a promising complementary treatment option for managing osteoarthritis symptoms.
Roshani M et al. · Explore (New York, N.Y.) (2025)
Borderline
The intervention groups showed significantly more significant reductions in mean pain scores than the control group (p < 0.05).
The mean score for daily functioning improved significantly over time in all groups (p = 0.007).
A decrease of 1.19 units per time increment was observed in the group using the ointment, while the oral capsule group showed a decrease of 0.89 units, both statistically significant (p = 0.006).