What Is Olive Leaf Extract?

The extract may help infections, inflammation, and certain conditions

Olive leaf softgels, capsules, and tincture

Verywell / Anastasia Tretiak

Long used in traditional medicine, olive leaf extract comes from the leaves of the olive tree (Olea europaea) and has a variety of health benefits. Research shows oleuropein, the main component in olive leaf extract, has antioxidant, antibacterial, antimicrobial, anti-inflammatory, and immune-stimulating properties.

Historically, olive leaf extract has been used for the prevention or treatment of a variety of inflammation and infections. This article looks at the possible health benefits, along with side effects, dosage and preparation, and more.

What Is Olive Leaf Extract Used For?

Although there is currently a lack of clinical trials testing the health effects of olive leaf extract, some preliminary studies have given support to the following potential benefits:

Here's a look at some key findings from the available research.


Olive leaf extract may aid in diabetes control, according to a small study published in the Journal of Medicinal Food. For the study, 79 adults with type 2 diabetes took either a supplement containing olive leaf extract or a placebo every day for 14 weeks. By the study's end, participants given olive leaf extract showed a significantly greater decrease in blood sugar levels compared to members of the control group.

While this study sample size is small, it replicates earlier animal studies and shows promise in the treatment of type 2 diabetes. However, more research is needed.

High Blood Pressure

Olive leaf extract shows promise in the treatment of hypertension, as is supported by a 2017 study published in the European Journal of Nutrition which found that phenolic-rich olive leaf extract reduces blood pressure. 

Researchers gave 60 prehypertensive subjects either olive leaf extract—136 milligrams (mg) oleuropein; 6 mg hydroxytyrosol—or a placebo for six weeks while monitoring blood pressure and found clinically significant reductions in blood pressure, total cholesterol, LDL cholesterol, and inflammatory markers in the treatment group.

While this was a small study, it replicated previous human research and animal studies, and shows promise for olive leaf extract as a treatment for high blood pressure.


Olive leaf extract has antiviral properties and is used in holistic medicine to treat certain viruses. In laboratory testing, olive leaf extract was shown to effectively fight herpes, mononucleosis, and rotavirus, and it may also be useful against influenza and HIV.

While the research is limited to cell cultures and olive leaf extract's benefits have not been proven human studies, strong anecdotal evidence suggests it can effectively treat cold sores. 

Olive leaf extract capsules
Verywell / Anastasia Tretiak

Dosage and Preparation

Olive leave comes in capsules, softgels, and tinctures. There is no recommended daily allowance for olive leaf extract. The standard dose ranges from 500 mg to 1,000 mg daily. Most supplement labels recommend splitting the dose, taking 250 mg to 500 mg two to four times a day with food.

Possible Side Effects

Due to a lack of research, little is known about the safety of regular use of supplements containing olive leaf extract. However, there's some concern that olive leaf extract may trigger mild side effects like stomach pain and headache.

Some people may develop an allergy to olive leaf extract. The pollen from the olive leaf can trigger severe respiratory allergic reactions in people who are allergic to plants in the Oleaceae family, including:

  • Ash trees
  • Forsythia
  • Jasmine
  • Lilacs
  • Olive trees
  • Rivets


Olive leaf extract may interact with certain medicines. Do not take olive leaf without consulting your healthcare provider if you are taking the following:

  • Blood pressure medications, as it can cause your pressure to get too low
  • Insulin or other blood sugar medicine, as it may cause hypoglycemia
  • Certain chemotherapy drugs, due to its antioxidant properties

What to Look For

When selecting a brand of supplements, look for products that have been certified by one of the following:

  • ConsumerLab
  • NSF International
  • U.S. Pharmacopeia

It's important to keep in mind that supplements haven't been tested for safety and dietary supplements are largely unregulated. In some cases, the product may deliver doses that differ from the specified amount for each herb.


Olive leaf extract may help people with hypertension, diabetes, cold sores, and more, but science isn't settled. Research continues to look into how the antioxidant, antibacterial, antimicrobial, anti-inflammatory, and immune-stimulating properties of olive leaf extract may offer health benefits. Be sure to talk with your healthcare provider about side effects, drug interactions, and other concerns before adding olive leaf extract to your diet.

Frequently Asked Questions

Can olive leaf extract help me lose weight?

Olive leaf extract has been shown to prevent obesity in animal studies. Researchers believe it works by regulating the expression of genes that affect weight gain and may also serve as an appetite suppressant. These results have not been replicated in human trials.

How should olive leaf extract be stored?

According to supplement makers, olive leaf extract should be stored in a cool, dark place, such as a cabinet or the refrigerator.

A Word From Verywell

Due to the limited research, it's too soon to recommend olive leaf extract as a treatment for any condition. It's also important to note that self-treating a condition and avoiding or delaying standard care may have serious consequences. If you're considering using olive leaf extract for any health purpose, make sure to consult your healthcare provider first.

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8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  3. Lockyer S, Rowland I, Spencer JPE, Yaqoob P, Stonehouse W. Impact of phenolic-rich olive leaf extract on blood pressure, plasma lipids and inflammatory markers: a randomised controlled trial. Eur J Nutr. 2017;56(4):1421-1432. doi:10.1007/s00394-016-1188-y

  4. Omar SH. Oleuropein in olive and its pharmacological effects. Sci Pharm. 2010;78(2):133-54. doi:10.3797/scipharm.0912-18

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