olive leaf extract

Olive leaf extract is a botanical supplement made from the leaves of the olive tree (Olea europaea), the same plant that gives us olives and olive oil. The leaves contain plant compounds known as polyphenols, and many extracts are standardized to oleuropein, typically the most abundant of these compounds. It is sold in several forms, including capsules, softgels, liquids, and teas.

No US-government health agency publishes a dedicated summary of olive leaf extract: there is no NIH Office of Dietary Supplements fact sheet, no NCCIH "Usefulness and Safety" page, and no MedlinePlus health topic for it, so no authoritative government verdict on its effectiveness is available here. Independent human evidence is limited overall. Some early human and animal data suggest olive leaf extract may modestly lower blood pressure, but findings for blood sugar, immune or antimicrobial effects, and cholesterol come largely from laboratory and animal work, with human studies that are small, short, or lacking. Across the board, it has not been shown to prevent, treat, or cure any disease. The uses listed above reflect why people take it, not benefits that have been proven in people.

There is no established or government-recommended dose for olive leaf extract, and products differ widely in oleuropein content and serving size, so doses on labels are not standardized or independently verified. Because dietary supplements are not reviewed by the FDA for effectiveness before they are sold, and the right amount (if any) for an individual is unknown, talk with your doctor, pharmacist, or another qualified clinician before starting it — especially if you take any medication or have a health condition.

Olive leaf and its extracts appear to be reasonably well tolerated at the amounts used in studies, but long-term safety has not been well established, and government safety reviews are not available. If you are pregnant or breastfeeding, have a medical condition, or take prescription medicines, check with a clinician before use. Stop use and seek medical care if you notice signs of an allergic reaction. Because supplement quality and labeling can vary, choose products from reputable manufacturers, ideally with independent third-party testing.

Reported effects are usually mild and may include digestive upset or headache. Allergic reactions are possible, particularly in people sensitive to olive or related plants; note that olive-tree pollen is a recognized cause of respiratory allergy. Because olive leaf extract may lower blood pressure or blood sugar, it could in theory cause lightheadedness or low readings in susceptible people. Data on side effects are limited, so unexpected reactions cannot be ruled out.

Olive leaf extract may add to the effect of blood-pressure-lowering and diabetes (blood-sugar-lowering) medicines, potentially pushing your numbers too low, though the clinical importance of this is not fully established. It could also interact with other drugs, and supplement-drug interactions for it are not well studied. Tell your doctor and pharmacist about every supplement you take, particularly before surgery or if you take medicines for blood pressure, diabetes, or blood thinning.