Olive Leaf Extract

Supplements · Immune & Antimicrobial Herbs · Supplement, Typed Supps

A concentrated extract of the compound also found in olive oil — with a small, real effect on blood pressure.

Stage by stage

Intake (Extract capsule): Active oleuropein compound absorbed in the small intestine.
Small intestine (Absorbed): Absorbed alongside other plant compounds.
Bloodstream (Antioxidant activity): Circulates with antioxidant activity.
Blood pressure & immune markers (Modest studied effects): Studied for modest effects on blood pressure and immune-related markers.

What the evidence supports

Modestly lowering blood pressure — limited evidence. A meta-analysis of small randomised trials found systolic reductions of a few mmHg, somewhat larger in people who were already hypertensive, but the trials are small and heterogeneous.
Improving cholesterol or general immune resistance — insufficient evidence. Effects on lipids and immunity are proposed from the oleuropein content but not established in good human trials.

Typical dose

500–1,000 mg/day of a standardised extract, delivering roughly 100–140 mg oleuropein, is the range used in trials

Upper limit: No established UL

Timing

With food, standard dosing.

Time to effect

Weeks: Any reported blood pressure or immune effect in studies.

Medication interactions

Blood-pressure medication: May add to the blood-pressure-lowering effect, risking readings that are too low. (moderate)
Diabetes medication: May lower blood glucose further, adding to the risk of hypoglycaemia. (moderate)

Common myth

“Olive leaf extract is as well-studied as olive oil itself.” In reality: Whole olive oil, especially extra virgin, has a far larger and more consistent research base than the concentrated leaf extract.