Olive Leaf Extract for Elevated Blood Pressure

The short answer: olive leaf extract has a modest and inconsistent effect on high blood pressure. A 2022 meta-analysis of 12 studies with 819 participants found systolic pressure 3.86 mmHg lower than control, and 4.81 mmHg lower in people with hypertension (Razmpoosh 2022). In the largest trial, 621 people already on treatment, 24-hour systolic pressure fell 6.4 mmHg with the extract against 1.5 mmHg with placebo over 12 weeks (Lamti 2025).

Other trials were less encouraging. Placebo-controlled trials in 56 adults with systolic pressure of 130 mmHg or more, and in 77 overweight adults, found no significant blood pressure difference (Lauwers 2026; Stevens 2021). We rate it mixed: a plausible add-on for mildly raised blood pressure, with an effect smaller than lifestyle changes or medicines, and not a replacement for either.

Olive leaves are rich in oleuropein and hydroxytyrosol, polyphenols (plant compounds) that most trials used to standardise their extracts. In isolated rabbit hearts and cultured rat heart cells, an olive leaf extract lowered left ventricular pressure and heart rate and directly, reversibly blocked L-type calcium channels (Scheffler 2008), the same target as calcium channel blocker drugs.

A second line of evidence comes from the lipid and metabolic effects seen alongside the blood pressure changes: lower LDL cholesterol and triglycerides in some trials (Lockyer 2017; Fladerer-Grollitsch 2026), and better insulin sensitivity in overweight men (de Bock 2013). These are markers of overall cardiovascular risk, not proof of a blood pressure mechanism.

The calcium-channel finding comes from animal tissue exposed to extract directly, not from people taking capsules, and it says nothing about how much oleuropein reaches blood vessels. In the crossover trial in 60 men, blood pressure fell slightly while vascular function markers did not change (Lockyer 2017).

Extracts also differ. Oleuropein in African wild olive leaf extracts ranged from undetectable to 59.4 mg/g depending on where the leaves were collected (Mmopele 2018), so a mechanism shown with one extract may not carry over to another product.

Trials used 500 to 1,000 mg of extract a day. The captopril comparison used 500 mg twice daily (Susalit 2011), and in the twin study only the 1,000 mg daily dose lowered blood pressure (Perrinjaquet-Moccetti 2008). By oleuropein content, the positive crossover trial used 136 mg a day (Lockyer 2017) and the combination trial at least 160 mg a day (Fladerer-Grollitsch 2026); the null 8-week trial used about 124 mg (Lauwers 2026). The largest trial's abstract doesn't state its dose (Lamti 2025).

Label reality matters: extracts are standardised differently, and oleuropein content can vary widely between leaf sources (Mmopele 2018). Choose a product that states its oleuropein content per dose. No blood pressure trial lasted longer than 12 weeks, so there's no evidence on long-term use.

Lamti 2025 is the largest trial: a multicentre, double-blind study of 621 people already treated for hypertension. After 12 weeks, 24-hour systolic pressure had fallen 6.4 mmHg with olive leaf extract against 1.5 mmHg with placebo (P < 0.01), and the share of readings above the threshold (systolic blood pressure load) fell from 53.9% to 42.2%. Lockyer 2017, a double-blind crossover trial in 60 pre-hypertensive men, found 24-hour systolic 3.33 mmHg lower and diastolic 2.42 mmHg lower than with control after 6 weeks.

In Fladerer-Grollitsch 2026, 70 adults with untreated mildly to moderately raised pressure took 1,000 mg olive leaf extract with 300 mg potassium a day; office pressure fell in both groups, but morning home systolic fell 5.4 mmHg more than with placebo. Because the product also contained potassium, the result can't be credited to the extract alone.

Susalit 2011 compared 500 mg twice daily with captopril 12.5-25 mg twice daily in stage 1 hypertension. After 8 weeks systolic pressure had fallen 11.5 mmHg with the extract and 13.7 mmHg with captopril, from about 149/94 mmHg, with no significant difference between groups. Without a placebo arm, it can't show how much of that fall was the extract.

Perrinjaquet-Moccetti 2008 was an open study of 40 borderline hypertensive twins. Blood pressure fell from 137/80 to 126/76 mmHg on 1,000 mg a day but didn't change on 500 mg a day or lifestyle advice. Its double-digit figures are often quoted, but an unblinded study of 20 twin pairs is weak evidence.

Three placebo-controlled trials found no significant blood pressure effect. In 56 adults with systolic pressure of 130 mmHg or more, systolic fell 8.3 mmHg with an olive extract and 7.3 mmHg with placebo (Lauwers 2026). In 77 overweight adults with raised cholesterol, 500 mg a day for 8 weeks changed neither lipids nor blood pressure (Stevens 2021), and in 46 overweight men, ambulatory blood pressure was unchanged after 12 weeks (de Bock 2013). Only the first selected people by blood pressure, and at a modest threshold.

The reviews reflect this. Razmpoosh 2022 pooled 12 studies (819 people) and found systolic 3.86 mmHg lower. Ismail 2021 found 500 mg a day lowered systolic pressure by 5.78 mmHg but judged the five trials too few and small for a robust conclusion. Lachovicz 2025 reported an 11.45 mmHg fall at 1,000 mg a day, but from three studies analysed before and after rather than against a control. A 2026 review of 11 trials found no significant effect on glucose or lipids (Câmara Rocha Menezes 2026).

Olive leaf extract was well tolerated in the trials. The 621-person trial reported no significant adverse events (Lamti 2025), the combination trial reported no product-related serious adverse events (Fladerer-Grollitsch 2026), and a 24-week pilot in type 2 diabetes found no severe or serious adverse events (Leach 2025). In the 8-week Belgian trial, side effects such as muscle pain and headache were no more common than on placebo (Lauwers 2026).

No trial lasted more than 24 weeks, and none we found included pregnant or breastfeeding women. The bigger risk is relying on a supplement with a 4 mmHg average effect instead of treatment that works: NHLBI notes many people need two or more medicines to manage high blood pressure (NHLBI).

Lifestyle changes come first. NHLBI recommends a heart-healthy eating plan such as DASH, noting that DASH combined with a low-salt diet can be as effective as medicines; limiting alcohol; regular physical activity, even 10 minutes of walking a day; losing 3-5% of body weight if you're overweight; quitting smoking; managing stress; and 7-9 hours of sleep (NHLBI). When those aren't enough, ACE inhibitors, angiotensin receptor blockers, calcium channel blockers and thiazide diuretics are the standard medicines.

If you want a supplement with more consistent trial evidence, see potassium for high blood pressure and garlic extract for high blood pressure.

Interactions in people haven't been studied directly. The likeliest is an additive effect with blood pressure medicines; the largest trial was run in treated patients without significant adverse events (Lamti 2025). Glucose effects are inconsistent: one trial in type 2 diabetes found lower HbA1c (Wainstein 2012) and the large blood pressure trial lower blood glucose (Lamti 2025), while a later pilot and a 2026 meta-analysis found no significant effect (Leach 2025; Câmara Rocha Menezes 2026). If you also have type 2 diabetes, monitor your glucose.

In a cell model, an African wild olive leaf extract increased the absorption of propranolol and diltiazem, which could raise their blood levels, but this hasn't been checked in people (Mmopele 2018).