Does olive leaf extract lower blood pressure or blood sugar?

Olive leaf extract has some human evidence behind it for blood pressure, but the effect in trials is small, and the blood sugar evidence is mixed. A 2022 meta-analysis of 12 trials (819 people) found an average systolic drop of about 3.9 mmHg and no meaningful change in glucose measures. That is a modest result from specific extracts at specific doses, and it is not a substitute for prescribed treatment.

The bigger problem for shoppers is the label. Most olive leaf claims on sales pages lean on a trial dose, while the capsule hides its own amount inside a blend. This guide covers what the studies used, where the evidence is thin, and how to compare a product with the research. It is general information, not medical advice.

What do the blood pressure trials actually show?

The results are positive on average, but they vary a lot between trials and are small in size. Here are the ones we opened:

• Stage-1 hypertension, 8 weeks: an Indonesian trial gave 500 mg of one branded olive leaf extract twice a day and compared it with the drug captopril. Systolic pressure fell by 11.5 mmHg on olive leaf extract and 13.7 mmHg on captopril, and the difference between the two groups was not statistically significant. There was no placebo group.
• Pre-hypertensive men, 6 weeks: a crossover trial of 60 men used an extract providing 136 mg of oleuropein a day. Daytime systolic pressure came out about 4 mmHg lower than on the control, and 24-hour systolic pressure about 3.3 mmHg lower. About half of the funding came from the extract's manufacturer.
• Treated hypertension, 12 weeks: a 2025 trial of 621 people already treated for high blood pressure reported that 24-hour systolic pressure fell by 6.4 mmHg from baseline on olive leaf extract, against 1.5 mmHg on placebo. One author is affiliated with a pharmaceutical laboratory.
• Overweight adults, 8 weeks: a trial of 77 people with mildly raised cholesterol gave 500 mg of extract or placebo. It found no significant difference in lipids or blood pressure.

Put together, a 2022 meta-analysis pooled 12 controlled trials with 819 participants. It reported a systolic drop of 3.86 mmHg (95% confidence interval 1.28 to 6.44) and a triglyceride drop of 9.51 mg/dl. The effects were larger in people who already had hypertension. For comparison, the NCCIH page on hypertension says the effects of supplements on blood pressure are small and that no dietary supplement has been shown to match the effects of blood pressure drugs. That page lists cocoa, garlic, fish oil, flaxseed, tea, probiotics and hibiscus; olive leaf is not on it.

Does olive leaf extract lower blood sugar?

The honest answer is "maybe a little, in some people, and the evidence is not consistent." The most-cited human study is a 2013 New Zealand crossover trial in 46 overweight, middle-aged men. They took capsules providing 51.1 mg of oleuropein and 9.7 mg of hydroxytyrosol a day for 12 weeks. Insulin sensitivity was 15 percent better than on placebo and pancreatic beta-cell responsiveness was 28 percent better. The same trial found no effect on blood pressure, lipids or body composition. The extract maker supplied the capsules and co-funded the project.

Other reviews read the sugar data differently. The 2022 meta-analysis found no meaningful change in glucose measures, and rated the quality of that evidence low to very low. A 2024 review of 12 trials (703 adults) reported that four trials showed a positive link with glucose metabolism, then asked for more consistent studies before firm conclusions. The 8-week trial in overweight adults above also found no change in glucose or insulin.

So a fair summary for a shopper: olive leaf extract is a reasonable subject for research, but a sales page that promises steady blood sugar numbers is going further than the trials do. If you have diabetes, a change in supplements is a conversation for your doctor or pharmacist, especially if you take glucose-lowering medicine. Our blood sugar category shows how offers in that space compare.

Why does the dose on the label matter so much?

Because the studies above did not use "olive leaf" in general. They used defined extracts, and the amounts differ more than most people expect. One trial used 500 mg of extract twice a day (1,000 mg total). Another reported its dose as 136 mg of oleuropein. A third reported 51.1 mg of oleuropein. Oleuropein is only a fraction of an extract's weight, so 136 mg of oleuropein and 1,000 mg of extract are not the same statement.

That is why a label that says only "olive leaf extract" with no milligrams and no oleuropein percentage cannot be matched to any trial. Three things to look for:

1. The milligrams of olive leaf extract per serving, not just per blend.
2. The standardization, for example "x% oleuropein" or "x% hydroxytyrosol."
3. The number of capsules in a serving, since trial doses are often split across the day.

Our review method checks exactly this: whether the labeled amount is close to what the cited research used.

How do olive leaf products on sales pages compare?

We have reviews of several offers that contain olive leaf. We repeat what each review found and do not add anything new.

The Cardio Shield review describes hawthorn, hibiscus, olive leaf, green tea, garlic and nattokinase folded into one 570 mg proprietary blend. The ingredients have published research, but the label does not say how much of any one of them you get. The review credits a 180-day refund window as a real strength.

The Blood Pressure 911 review is a good example of the dose gap. The page leans on a study using 136 mg of oleuropein (the 60-man trial above), while the capsule shares 620 mg between seven herbs, so the match cannot be checked. The review also flags a sales letter that suggests using the capsule with or instead of prescriptions, which is exactly what the NCCIH warns against.

The MemoVolt review and the Neuro Serge review show a different pattern. In both, olive leaf is one of many ingredients with no amount stated, and in Neuro Serge the review notes that its ingredient benefits are mostly about heart health and blood sugar rather than the brain claim in the pitch. NeuroZoom lists olive leaf among a long ingredient list with amounts not stated.

The pattern across these reviews: the research is real, but the label rarely lets you compare. For more options in the same area, browse our heart health category.

Is olive leaf extract safe, and who should ask first?

The 2025 trial of 621 people reported no significant adverse events over 12 weeks. We did not find long-term safety data in the sources we opened, and that does not make an extract safe for everybody, since trials last weeks, not years.

Two situations call for a conversation with a doctor or pharmacist before you start:

• You take blood pressure or diabetes medicine. The NCCIH warns that some supplements can interact with medicines, including those used for high blood pressure. If an extract does lower pressure or sugar, it could add to a prescription.
• You are pregnant, nursing, planning surgery, or buying for a child. NCCIH notes that many dietary supplements have not been tested in pregnant women, nursing mothers or children, and that some can affect bleeding or anesthesia.

If you have high blood pressure, follow the plan your health care provider gave you. Do not swap a prescription for a capsule because a sales page says so.

What should you check before buying olive leaf extract?

1. Find the olive leaf amount in milligrams. If it sits inside a proprietary blend, you cannot tell your dose.
2. Look for an oleuropein or hydroxytyrosol percentage, and compare it with the trial numbers above.
3. Check whether the cited study tested the same extract and a similar amount.
4. Read who paid for the study. Several of the trials above had manufacturer funding, which is not a reason to dismiss them but is worth knowing.
5. Be wary of any page that suggests stopping or replacing a prescription.
6. Check the refund terms before ordering. See our ClickBank refund guide for how to claim one.

FAQ

Does olive leaf extract lower blood pressure?

In some trials it did, by a few mmHg on average. A 2022 meta-analysis of 12 trials reported about 3.9 mmHg lower systolic pressure. One 77-person trial using 500 mg found no difference, so results are not consistent.

How much olive leaf extract was used in studies?

One trial used 500 mg of a branded extract twice a day for 8 weeks. Others reported dose as oleuropein: 136 mg a day in one, 51.1 mg a day in another. A label must tell you its extract amount and standardization before you can compare.

Can olive leaf extract replace blood pressure medicine?

No. The NCCIH states that no dietary supplement has been shown to have effects comparable to those of drugs used to treat hypertension, and advises people not to replace prescribed treatment with an unproven product. The captopril comparison trial had no placebo group, so it cannot show that an extract can stand in for a drug.

Does olive leaf extract help with blood sugar?

One 12-week trial in overweight men found better insulin sensitivity, but a 2022 meta-analysis found no meaningful change in glucose measures and rated the evidence low. Talk to your doctor before using it with diabetes medicine.