What Is Olive Leaf Extract?

The extract may help infections, inflammation, and certain conditions

Olive leaf softgels, capsules, and tincture

Verywell / Anastasia Tretiak

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Olive leaf extract has long been used in traditional medicine. It comes from the leaves of the olive tree (Olea europaea) and has many health benefits. 

The main component of olive leaf extract is oleuropein. Medicinally, it acts as an:

This article looks at the possible health benefits of olive leaf extract, along with side effects, dosage and preparation, and what to look for when buying it.


Medical research on olive leaf extract is in its early stages. Some preliminary studies suggest it may help treat:

So far, research is strongest for its use in:


Olive leaf extract may aid in diabetes control. In one study, 79 adults with type 2 diabetes took either olive leaf extract or a placebo every day for 14 weeks.

In the end, the olive leaf extract group had significantly more improvement in blood sugar levels than the control group.

While this study was small, it supports findings from earlier animal studies. Still, more research is needed.

High Blood Pressure

Olive leaf extract shows promise for treating hypertension. In a small study comparing olive leaf extract to placebo, researchers found olive leaf lowered:

Again, this was a small study that built on previous research. It may lead to larger studies that offer more complete information about safety and effectiveness.


Olive leaf extract has antiviral properties. It's used in holistic medicine to treat certain viruses.

Lab tests show olive leaf extract can fight herpes, mononucleosis, and rotavirus. It may also be useful against influenza and HIV.

This research has been limited to cell cultures. The benefits remain to be proven in human studies. However, anecdotal evidence suggests it can effectively treat cold sores. 

Olive leaf extract capsules
Verywell / Anastasia Tretiak

Dosage and Preparation

Olive leave extract supplements come in capsules, softgels, and tinctures. The standard dose ranges between 500 milligrams (mg) and 1,000 mg daily.

Most supplement labels recommend splitting the dose. That gives you between 250 mg and 500 mg. It should be taken two to four times a day with food.

Always follow the instructions on the label when taking supplements. Or talk to your healthcare provider about the dosage that's right for you.


Olive leaf extract is an antioxidant, anti-inflammatory, and antimicrobial. It's claimed to help manage many conditions, but research best supports just a few: diabetes, high blood pressure, and viral illnesses.

There are no standard guidelines on dosages. Most supplement labels recommend between 500 mg and 1,000 mg, sometimes divided into up to four doses, per day.

Possible Side Effects

Little is known about the safety of regularly taking olive leaf extract. But there's some concern it 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 allergic to plants in the Oleaceae family, including:

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


Olive leaf extract may interact with certain medicines. Unless your healthcare provider approves it, don't take it if you're on:

  • Blood pressure medications, as it may cause hypotension (low blood pressure)
  • Insulin or other blood sugar medicine, as it may cause hypoglycemia (low blood sugar)
  • Certain chemotherapy drugs, due to its antioxidant properties

Chemo + Antioxidants?

The use of antioxidants during chemotherapy is controversial. Some oncologists (cancer specialists) believe it could prevent drugs from killing cancer cells. But some research suggests it may make chemotherapy drugs more effective while also curbing their side effects.

What to Look For

Supplements aren't tested and regulated like drugs. Sometimes, the dosages and ingredients on the label don't match what's in the bottle.

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

  • ConsumerLab
  • NSF International
  • U.S. Pharmacopeia

These are independent labs that evaluate supplements for purity. They help ensure you're getting what the label says. They don't guarantee safety and effectiveness, however.


Olive leaf extract may help treat hypertension, diabetes, cold sores, and more, but science isn't settled. Research continues to look into how the medicinal properties of olive leaf extract may be used.

Be sure to talk with your healthcare provider before taking olive leaf extract or any supplement. Watch for side effects and drug interactions when you add olive leaf extract to your diet.

If you're allergic to related plants—including forsythia, ash, and olive trees—you may be allergic to olive leaf extract, as well.

A Word From Verywell

Research isn't yet certain enough to recommend olive leaf extract for any condition. Self-treating a condition and avoiding or delaying standard medical care may have serious consequences.

If you're considering olive leaf extract for any health purpose, talk to your healthcare provider first.

Frequently Asked Questions

  • Can olive leaf extract help me lose weight?

    It might. In animal studies, olive leaf extract has been shown to prevent obesity. Researchers think it works by regulating the expression of genes that affect weight gain. It may also be an appetite suppressant. These results haven't been confirmed in human trials.

  • How should olive leaf extract be stored?

    Supplement makers say to store olive leaf extract in a cool, dark place, such as a cabinet or the refrigerator.

11 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.
  1. Memorial Sloan Kettering Cancer Center. Olive leaf.

  2. Wainstein J, Ganz T, Boaz M, et al. Olive leaf extract as a hypoglycemic agent in both human diabetic subjects and in rats. J Med Food. 2012;15(7):605-10. doi:10.1089/jmf.2011.0243

  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

  5. Motamedifar M, Nekooian AA, Moattari A. The effect of hydoralcoholic extract of olive leaves against herpes simplex virus type 1. Iran Journ Med Sci. Dec 2007;32(4):222-226.

  6. Basch, EM, Ulbricht, C. Natural standard herb & supplement guide. New York, NY: Elsevier Health Sciences

  7. 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 trialEur J Nutr. 2017;56(4):1421-1432. doi:10.1007/s00394-016-1188-y

  8. Abdel-Kader MS, Soliman GA, Abdel-Rahman RF, Saeedan AS, Abd-Elsalam RM, Ogaly HA. Effect of olive leaves extract on the antidiabetic effect of glyburide for possible herb-drug interactionSaudi Pharm J. 2019;27(8):1182-1195. doi:10.1016/j.jsps.2019.10.001

  9. Singh K, Bhori M, Kasu YA, Bhat G, Marar T. Antioxidants as precision weapons in war against cancer chemotherapy induced toxicity - Exploring the armoury of obscuritySaudi Pharm J. 2018;26(2):177-190. doi:10.1016/j.jsps.2017.12.013

  10. Consumer Reports. How to choose supplements wisely.

  11. Shen Y, Song SJ, Keum N, Park T. Olive leaf extract attenuates obesity in high-fat diet-fed mice by modulating the expression of molecules involved in adipogenesis and thermogenesis. Evid Based Complement Alternat Med. 2014;2014:971890. doi:10.1155/2014/971890

Additional Reading

By Cathy Wong
Cathy Wong is a nutritionist and wellness expert. Her work is regularly featured in media such as First For Women, Woman's World, and Natural Health.