Olive leaf extract benefits: what it does and what the research shows

What is olive leaf extract?

Olive leaf extract is a concentrated preparation made from the leaves of the olive tree, Olea europaea.

It is different from olive oil, which is pressed from the fruit. The leaves contain plant compounds called polyphenols, the best known of which is oleuropein. Supplements are usually sold as capsules or liquids, often standardised to a stated amount of oleuropein.

Olive leaf has a long history in Mediterranean herbal practice. In our olive leaf ingredient guide we describe it in those terms: traditionally used to support immune and heart health. As a botanical, it has no authorised health claim, so we stick to describing tradition and research.

What does olive leaf extract do?

Olive leaf extract has been studied mainly for blood pressure and blood fats, with modest and mixed results.

Most of the human research has looked at adults with raised or borderline blood pressure. The findings are interesting, but the trials are small, and the reviews that pool them do not all agree.

What does the research say about blood pressure?

Reviews suggest a small average drop in systolic blood pressure, but the evidence is low certainty.

Study	Who took part	What it found
Susalit and colleagues, 2011	Adults with stage 1 high blood pressure	500 mg twice a day for 8 weeks lowered systolic pressure by 11.5 mmHg, compared with 13.7 mmHg for the medicine captopril. The difference was not statistically significant.
Systematic review, 2021	5 trials, 325 adults with raised or high blood pressure	500 mg a day lowered systolic pressure by about 5.8 mmHg compared with control in two trials. Other comparisons showed no significant difference. Certainty of evidence was low.
Systematic review, 2022	12 trials in the general adult population	Systolic pressure fell by about 3.9 mmHg and triglycerides fell slightly. There was no significant effect on diastolic pressure or blood sugar markers.

The 2011 trial is often quoted because olive leaf extract performed similarly to a blood pressure medicine. A single trial like this does not prove the two are equivalent, and nobody should swap prescribed medicine for a supplement.

The reviewers behind the 2022 analysis called for stronger trials testing different doses and durations. That is a fair summary of where the science sits.

What about blood fats?

The 2022 review found a small reduction in triglycerides, a type of fat in the blood. It found no meaningful changes in blood sugar control, liver or kidney markers, or inflammation markers.

Does olive leaf extract support the immune system?

Olive leaf is traditionally used to support immune health, but good human trials on immunity are lacking.

You will see bold immune claims for olive leaf online. We would treat those with caution. The honest position is that its immune reputation rests on tradition and laboratory interest, not on solid evidence in people.

If immune support is your main goal, nutrients with authorised claims are a better starting point. Vitamin C, vitamin D and zinc each contribute to the normal function of the immune system.

Is olive leaf extract the same as olive oil?

No. They come from different parts of the tree and have different evidence behind them.

The European Food Safety Authority has assessed olive oil polyphenols. The authorised claim is that they contribute to the protection of blood lipids from oxidative stress, for olive oil providing at least 5 mg of hydroxytyrosol and related compounds per 20 g of oil a day. That claim applies to olive oil only. It is not a dose guide for olive leaf extract.

The European Medicines Agency recognises olive leaf as a traditional herbal medicine for a different purpose: to help the kidneys flush water in mild water retention, once a doctor has ruled out anything serious.

Is olive leaf extract safe?

Olive leaf extract is generally well tolerated in trials, but some people need to check first.

• Blood pressure medicines. Because olive leaf has been studied for lowering blood pressure, taking it alongside blood pressure medicine could add to the effect. Speak to your GP or pharmacist first, and never stop or change prescribed medicine yourself.
• Diabetes medicines. If you take medicine to lower blood sugar, ask your GP or pharmacist before adding any herbal supplement.
• Pregnancy and breastfeeding. The European Medicines Agency says safety has not been established and use is not recommended.
• Low blood pressure. If you are prone to feeling dizzy or faint, check with your GP before trying it.

How do you choose an olive leaf supplement?

Look for a clearly labelled extract, a stated amount per serving, and a sensible daily dose.

The trials used around 500 mg to 1,000 mg of extract a day, but extracts vary in strength, so compare like with like. A good label lists the amount of extract and, ideally, its oleuropein content. Avoid products that promise to treat infections or replace medicine.

Where to go from here

We do not currently stock a dedicated olive leaf supplement, but our immune range brings together ingredients with stronger evidence or long traditional use.

You can read more in our olive leaf guide, and browse the immune collection. It includes NAC, which the body uses to make glutathione, and Liposomal Glutathione. There is also our Immune Boost Protocol, a bundled option from the same range. If you take regular medicine, a quick check with your pharmacist is always a good idea.