Olive
Standardised olive leaf extract (typically 20% oleuropein) has modest evidence for lowering mild-to-moderate blood pressure and improving LDL cholesterol, supported by a few small RCTs including one head-to-head non-inferiority trial against captopril. Antiviral, antimicrobial, and antitumour claims are based mostly on cell and animal studies; human clinical translation is lacking.
Quick decision guide
May help most
Adults with stage-1 hypertension or borderline-elevated cholesterol seeking a plant-derived adjunct under clinician oversight; useful as part of a Mediterranean-style approach to cardiovascular risk.
Common dosing range
500–1,000 mg/day of leaf extract standardised to ~20% oleuropein, or ~100–140 mg/day total oleuropein from concentrated phenolic extracts.
When to expect effects
6–8 weeks for blood pressure and lipid changes.
Watch out for
Can add to the effect of antihypertensive and diabetes medications — monitor BP and blood sugar when starting or stopping. Possible mild antiplatelet effect; stop 1–2 weeks before surgery.
Evidence snapshot
What is it
Olive (Olea europaea) is a small evergreen tree native to the Mediterranean basin whose fruit and leaves have been used for thousands of years as food, oil, and medicine. In supplement form, olive leaf extract and concentrated olive polyphenol preparations are used for cardiovascular and immune support. Olive oil itself is a foundational component of the Mediterranean diet.
Is it worth it for you?
Use this as a quick fit check, not a diagnosis.
Worth considering if…
Probably skip if…
Evidence at a glance
| Goal | Effect | Best fit | Time |
|---|---|---|---|
Mild-to-moderate hypertension Good Evidence | SBP: −3 to −11 mmHg; DBP: −2 to −5 mmHg over 6–8 weeks at standardised doses | Adults with stage-1 hypertension or borderline-elevated BP not yet requiring multidrug therapy | 6–8 weeks |
LDL / total cholesterol Limited Evidence | Total cholesterol −5 to −15 mg/dL; LDL −5 to −10 mg/dL; triglycerides −10 to −15 mg/dL over 6–8 weeks | Adults with borderline-elevated cholesterol not yet on a statin | 6–8 weeks |
Insulin sensitivity / type 2 diabetes risk Limited Evidence | HOMA-IR improvement ~15% over 12 weeks in overweight men | Overweight pre-diabetic adults seeking botanical adjuncts to lifestyle change | 12 weeks |
Inflammatory markers and antioxidant status Limited Evidence | Modest improvements in oxidative-stress and inflammation surrogates | Adults at elevated cardiovascular risk seeking polyphenol-rich adjuncts | 6–12 weeks |
Antiviral / antimicrobial / 'immune support' Weak Evidence | Robust in vitro antimicrobial activity; no controlled human trials for clinical infection | None established for clinical infection | Not established clinically |
Mild-to-moderate hypertension
- Effect
- SBP: −3 to −11 mmHg; DBP: −2 to −5 mmHg over 6–8 weeks at standardised doses
- Best fit
- Adults with stage-1 hypertension or borderline-elevated BP not yet requiring multidrug therapy
- Time
- 6–8 weeks
LDL / total cholesterol
- Effect
- Total cholesterol −5 to −15 mg/dL; LDL −5 to −10 mg/dL; triglycerides −10 to −15 mg/dL over 6–8 weeks
- Best fit
- Adults with borderline-elevated cholesterol not yet on a statin
- Time
- 6–8 weeks
Insulin sensitivity / type 2 diabetes risk
- Effect
- HOMA-IR improvement ~15% over 12 weeks in overweight men
- Best fit
- Overweight pre-diabetic adults seeking botanical adjuncts to lifestyle change
- Time
- 12 weeks
Inflammatory markers and antioxidant status
- Effect
- Modest improvements in oxidative-stress and inflammation surrogates
- Best fit
- Adults at elevated cardiovascular risk seeking polyphenol-rich adjuncts
- Time
- 6–12 weeks
Antiviral / antimicrobial / 'immune support'
- Effect
- Robust in vitro antimicrobial activity; no controlled human trials for clinical infection
- Best fit
- None established for clinical infection
- Time
- Not established clinically
Evidence for 5 uses
AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.
Mild-to-moderate hypertension
Supplement benefitThe best single trial randomised 232 adults with stage-1 hypertension to olive leaf extract (EFLA943, 500 mg twice daily, ~20% oleuropein) versus captopril (12.5–25 mg twice daily) for 8 weeks. Both arms achieved ~11.5 mmHg systolic and ~4.8 mmHg diastolic reductions — olive leaf was non-inferior. A smaller crossover trial in pre-hypertensive men using a more concentrated phenolic extract (136 mg oleuropein) showed ~3 mmHg reductions over 6 weeks. A twin-pair pilot showed dose-dependent BP reductions at 500 and 1,000 mg/day. Effect is consistent across small trials in mild hypertension.
Bottom line: Real but modest BP effect at standardised doses. Useful adjunct, not a replacement for prescription therapy in higher-risk patients.
LDL / total cholesterol
Supplement benefitThe captopril head-to-head trial showed olive leaf reduced triglycerides by ~7.8 mg/dL over 8 weeks, while captopril nudged them up. The Lockyer 2017 crossover trial in pre-hypertensive men reported reductions in total cholesterol (~7 mg/dL), LDL (~5 mg/dL), and triglycerides (~13 mg/dL) over 6 weeks. EFSA approved a related health claim for olive OIL polyphenols and LDL oxidation protection at ≥5 mg hydroxytyrosol-derivative daily — overlapping but not identical to olive leaf extract. Magnitudes are modest and trials are small.
Bottom line: Modest lipid effect in line with other polyphenol-rich approaches. A small reasonable add-on in early dyslipidemia.
Insulin sensitivity / type 2 diabetes risk
Supplement benefitA 12-week randomised crossover trial in 46 overweight middle-aged men found olive leaf extract (51 mg oleuropein + 10 mg hydroxytyrosol/day) improved HOMA-IR by 15% and pancreatic β-cell responsiveness versus placebo. Plausible mechanism via olive polyphenols' antioxidant and anti-inflammatory effects. Trial is small and replication has been limited.
Bottom line: Promising but under-replicated. Reasonable as an adjunct, not as primary therapy for diabetes.
Inflammatory markers and antioxidant status
Biomarker supportOlive leaf polyphenols modestly improve markers of oxidative stress (MDA, ox-LDL) and inflammation (CRP, IL-6) in small trials, consistent with the broader EFSA-recognised effect of olive oil polyphenols on protecting blood lipids from oxidation. The clinical importance of these surrogate marker changes is unclear, but the direction is consistently favourable.
Bottom line: Direction is favourable but the clinical-endpoint value of these biomarker shifts is small.
Antiviral / antimicrobial / 'immune support'
Mechanism onlyOleuropein and its metabolite hydroxytyrosol show direct antibacterial activity against various Gram-positive and Gram-negative organisms in vitro, and antiviral activity against HIV, influenza, herpes, and respiratory viruses in cell and animal models. None of this has translated to controlled clinical trials in humans for infection prevention or treatment. Olive leaf marketed for COVID, flu, herpes, or 'immune support' has no clinical-trial backing for those uses.
Bottom line: Skip olive leaf for infection prevention or treatment. The preclinical hype hasn't been confirmed in trials.
Evidence is mixed
Strong preclinical data + heavy marketing claims, but no controlled clinical trial showing infection prevention or treatment. Don't use as a substitute for antibiotics, antivirals, or vaccines.
How it works
How to take it
What to track
Bottom line: 500 mg twice daily of 20%-oleuropein extract for 6–8 weeks, with BP measured weekly. Discuss with your clinician if you're already on cardiac or diabetes medication.
5 commercial forms
Compare the main delivery options and what they’re best suited for.
Standardised olive leaf extract (~20% oleuropein)
Most studiedDried leaf extract standardised to 18–20% oleuropein content (e.g. EFLA943, the form used in the captopril head-to-head trial). The benchmark for clinical evidence — when you see RCT-supported dosing, this is what was used. 500 mg twice daily is the studied dose.
Oleuropein and its metabolite hydroxytyrosol are absorbed and bioavailable after oral dosing.
Concentrated phenolic extract (Bonolive-type)
Higher polyphenol densityHighly concentrated extract delivering 100–140 mg oleuropein per dose from much less plant material. Used in the Lockyer 2017 pre-hypertensive crossover trial. Once-daily dosing is feasible.
Same active polyphenols at higher concentration per pill.
Whole olive leaf powder
Less standardisedCrushed dried olive leaf in capsules or tea. Oleuropein content varies widely with harvest, season, and processing. Not suitable when you want a clinically-relevant dose.
Variable; harder to dose-target than standardised extract.
Olive leaf tea (loose leaf or bag)
TraditionalHot-water infusion of dried leaf. Mediterranean folk-medicine use. Polyphenol delivery is modest and inconsistent vs standardised extracts; pleasant but not therapeutic-strength.
Lower polyphenol delivery per cup than standardised extract.
Liquid tincture (1:1 fluid extract)
Quality variesAlcohol- or glycerine-based liquid extract. Less commonly trialled than dried-extract capsules; oleuropein content per drop varies widely between manufacturers.
Standardisation is rare; clinical evidence base is weaker than capsules.
Safety
Know the common side effects, key cautions, and who should avoid it.
Common side effects
Serious risks
Symptomatic hypotension if combined with prescription antihypertensives — the BP-lowering effect is additive. Monitor closely when starting and reduce dose if dizziness occurs.
Additive hypoglycemia with diabetes medication — olive leaf modestly lowers glucose. Monitor closely if on insulin or sulfonylureas.
Possible mild antiplatelet effect — limited clinical data. Stop 1–2 weeks before surgery to be safe.
Who should avoid it
- People on multiple antihypertensives whose BP is already well-controlled — risk of symptomatic hypotension.
- People on insulin or sulfonylureas without endocrine input — risk of hypoglycemia.
- People allergic to olive pollen or olive products — cross-reactive allergy possible.
- Anyone within 2 weeks of scheduled surgery.
Pregnancy & breastfeeding
Olive leaf extract in supplement doses has not been adequately studied in pregnancy or breastfeeding. Olives and olive oil in normal food amounts are safe. Avoid supplement-dose olive leaf during pregnancy unless under obstetrician oversight.
Bottom line: Generally well-tolerated at studied doses. Watch for additive effects with BP and diabetes medications, and stop before surgery.
Interactions
Additive BP-lowering effect. Monitor BP weekly when starting; reduce one or other dose if symptomatic hypotension.
Additive hypoglycemia risk. Monitor blood glucose closely; dose-adjustment may be needed.
Possible mild additive antiplatelet effect; clinical relevance limited but stop 1–2 weeks before surgery.
Theoretical bleeding risk via mild antiplatelet effect; no major case-report literature. Monitor INR if on warfarin.
Olive leaf has mild diuretic action that could affect lithium clearance. Monitor lithium levels.
Food sources
| Food | Amount | %DV |
|---|---|---|
| Extra-virgin olive oil (high-polyphenol) | 1 tbsp / ~14 g (5–10 mg hydroxytyrosol-equivalents) | — |
| Black olives, ripe | 10 olives / ~40 g (~5 mg total polyphenols) | — |
| Green olives, brined | 10 olives / ~40 g (~3–5 mg polyphenols) | — |
| Olive leaf tea | 1 cup brewed from 1 g leaf (~10–20 mg oleuropein, variable) | — |
Extra-virgin olive oil (high-polyphenol)
- Amount
- 1 tbsp / ~14 g (5–10 mg hydroxytyrosol-equivalents)
- %DV
- —
Black olives, ripe
- Amount
- 10 olives / ~40 g (~5 mg total polyphenols)
- %DV
- —
Green olives, brined
- Amount
- 10 olives / ~40 g (~3–5 mg polyphenols)
- %DV
- —
Olive leaf tea
- Amount
- 1 cup brewed from 1 g leaf (~10–20 mg oleuropein, variable)
- %DV
- —
Choosing a product
What to look for on the label — and what to be skeptical of.
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Frequently asked questions
Should I use olive oil or take olive leaf extract?⌄
Extra virgin olive oil as part of a Mediterranean dietary pattern has the strongest cardiovascular evidence. Olive leaf extract is more concentrated in oleuropein and may have specific effects on blood pressure. They serve different purposes.
How much olive oil should I eat daily?⌄
Mediterranean dietary studies show benefit with 20 to 40 mL (about 1.5 to 3 tablespoons) of extra virgin olive oil daily. The EFSA-approved health claim requires at least 20 mg of hydroxytyrosol-type polyphenols daily.
Does olive leaf extract really lower blood pressure?⌄
Multiple trials show modest blood pressure reductions in prehypertension and mild hypertension. Effects are smaller than prescription medications but clinically meaningful for some users.
What's special about extra virgin olive oil?⌄
Extra virgin olive oil is cold-pressed and minimally processed, preserving the highest polyphenol content. Refined olive oils lose most polyphenols during processing, reducing the antioxidant benefits.
Are olives healthy too?⌄
Yes. Whole olives provide many of the same polyphenols as the oil, plus fiber. Sodium content from curing can be high, so moderate intake and choose lower-sodium varieties when possible.
References by claim
Track Olive with Pilora
Set up dose reminders, check interactions, and join the community in the Pilora iPhone app.
Coming to App StoreDisclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.