Olive Leaf Extract
An olive-tree leaf extract with small, early trials on blood pressure and blood sugar — promising, not proven.
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What it is
Olive leaf extract comes from the leaves of the olive tree (Olea europaea) and is rich in polyphenols, especially oleuropein and hydroxytyrosol. It's distinct from olive oil, which is pressed from the fruit.
How it works
Oleuropein and related polyphenols act as antioxidants and may help blood vessels relax, possibly by supporting nitric oxide and, in lab studies, by mildly blocking calcium channels in vessel walls. Some research suggests they may also improve how the body responds to insulin. These mechanisms are plausible, but most come from lab and animal work, and effects in people appear small.
What it's been studied for
Commonly taken for blood pressure, blood sugar, immune support, and general antioxidant benefits.
What the evidence shows
Early and modest. A few small randomized trials suggest olive leaf extract may modestly lower blood pressure in people with mildly elevated readings and improve insulin sensitivity in overweight adults, but a 2024 meta-analysis found results inconsistent across studies, and claims that it fights infections come mostly from lab studies. The key limitation is that trials are few, small, short, and use different extracts.
Who should consider it
Adults with mildly elevated blood pressure or blood sugar who are interested in a plant-based option might discuss it with their provider as a complement to diet, activity, and any prescribed treatment. People whose blood pressure or blood sugar is already controlled with medicines should be cautious about stacking effects. It's not a substitute for medical care, and anyone hoping it will replace a prescription should talk to their provider first.
Amounts commonly studied
Studies typically used extracts providing roughly 50 to 150 mg of oleuropein per day, or about 500 mg of extract taken once or twice daily, for 6 to 12 weeks.
How to take it
Studies typically used extracts providing about 50 to 150 mg of oleuropein daily, often with meals, for 6 to 12 weeks. If you take medicine for blood pressure or diabetes, check your numbers more often when starting and let your provider know.
Forms & absorption
Capsules or tablets of standardized extract (labeled by oleuropein content), liquid extracts, and tea. Polyphenol content varies widely between products, so the oleuropein amount matters more than total extract weight.
Food sources
None — olive leaf is used as an extract or tea rather than a food; olives and extra virgin olive oil contain related polyphenols like hydroxytyrosol, but in smaller amounts.
Safety & interactions
Generally well tolerated; mild stomach upset or headache is possible. It may add to the effects of blood-pressure-lowering and diabetes medicines, raising the risk of dizziness or low blood sugar, so talk to your provider and monitor your numbers more closely if you take them. Safety in pregnancy and breastfeeding isn't established, and people allergic to olive tree pollen may react.
Myths & what it won't do
Myth: olive leaf extract is a natural antibiotic that can clear infections. Reality: it kills microbes in lab dishes, but there's no good evidence it does so in people. Myth: it delivers the same benefits as a Mediterranean diet rich in olive oil. Reality: the olive oil research comes from whole dietary patterns and different compounds — a leaf capsule isn't a substitute for the diet.
Common questions
- Is olive leaf extract the same as olive oil?
- No. The extract comes from the leaves and is much more concentrated in oleuropein, while olive oil comes from the fruit and contains smaller amounts of related polyphenols along with healthy fats.
- Can it replace my blood pressure medicine?
- No. Small trials suggest modest effects at best, and it isn't a substitute for medical care. If you take blood pressure medicine, talk to your provider before adding it, since the effects could add up.
- How long before it works?
- Studies typically ran 6 to 12 weeks. If you and your provider decide to try it, checking your blood pressure or blood sugar before and after that window is the most honest way to judge whether it's doing anything for you.
The amounts listed here are what published research has used — not a prescription or a recommended dose for you. Confirm anything you plan to take with your own healthcare provider, especially if you take medications, are pregnant or nursing, or have a health condition.
Related goals
Research on Olive Leaf Extract
Recommendations on this page are informed by published research. This is educational information, not medical advice.
- Lockyer S, Rowland I, Spencer JPE, Yaqoob P, Stonehouse W. Impact of phenolic-rich olive leaf extract on blood pressure, plasma lipids and inflammatory markers: a randomised controlled trial. Eur J Nutr. 2017;56(4):1421-1432. View study →Note: Six weeks of olive leaf extract modestly lowered blood pressure and cholesterol in 60 men with slightly high blood pressure.
- Álvares AA, Garcêz A, Silva LT, Averbuch N, Garavaglia J. Olive leaf extract effect on cardiometabolic risk factors: a systematic review and meta-analysis of randomized clinical trials. Nutr Rev. 2024;82(12):1710-1725. View study →Note: Pooled trials gave inconsistent results for blood sugar, blood pressure, and lipids; the authors called for more consistent studies.