Olive Leaf Extract: The Ultimate Guide to This Powerful Herb

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Tatiana Alcazar
March 9, 2021

Olive Leaf Extract

A regular part of the Mediterranean diet, olives, olive leaf, and olive leaf extract also have a centuries-long history of use in Tunisia, Morocco, Greece and other countries as a traditional, natural treatment for a variety of symptoms and conditions, from high blood pressure to infections to constipation. 

The main active ingredient in olive leaf is a polyphenol called oleuropein. Polyphenols are a type of antioxidant, giving them many beneficial medicinal and therapeutic properties, including anti-inflammatory, antimicrobial, antiviral and anti-tumor properties as well as potentially helping to prevent osteoporosis, cancer and cognitive decline.

A secondary polyphenol in OLE is called oleacein. In addition to these, OLE contains an assortment other polyphenolic compound also attributing to those properties, including hydroxytyrosol, tyrosol and caffeic. (Sources: "Effects of the Olive-Derived Polyphenol Oleuropein on Human Health"; International Journal of Molecular Sciences"Hydroxytyrosol: Health Benefits and Use as Functional Ingredient in Meat"; Medicines)

Whereas the ancient Mediterranean cultures consumed the olive leaves they harvested directly from olive trees as a food, today, you can ingest only the active ingredient from olive leaves extracted into a convenient tincture known as olive leaf extract (OLE).  With similar benefits as olive oil, except in a much more concentrated form. In any form it may be, OLE offers an array of health benefits.

Conditions Olive Leaf Extract Benefits

People take olive leaf extract for a wide variety of conditions and symptoms. Many of those uses have even undergone extensive scientific study verifying their benefits. When available, those studies are referenced below.
olive leaf extract health benefits

Weak or Compromised Immune System

People with a weak or compromised immune system, such as the elderly and those with HIV or AIDS, struggle just to avoid catching the simple illnesses most people find so mild and fleeting, let alone the new global threat facing everyone of COVID-19. 

More than ever, those with a weak or compromised immune system face anxieties about their health and seek healthy and effective solutions to boost their natural immune response. (Source: "Oleuropein in Olive and its Pharmacological Effects"; Scientific Pharmaceutical)

Olive leaf extract may be one such solution.

Bacteria and Viruses; Olive Leaf Extract Antiviral


According to research and ancient tradition alike, OLE shows great promise for relieving and preventing colds, flus and other chronic illnesses.

In a review of research examining OLE's anti-microbial properties, called "Antimicrobial Efficacy of Olive Leaf Extract Antimicrobial Efficacy of Olive Leaf Extract: A systematic review of in vitro study" and published in 2016 in Advances in Bioresearch, multiple test-tube studies have verified and confirmed the anti-microbial properties of the compound.

Meanwhile, a 2007 review of research entitled "Colds and influenza: a review of diagnosis and conventional, botanical, and nutritional considerations" published in Alternative Medicine Review found that OLE halted the replication of the flu virus in animal studies.

The credit the Mediterranean diet is given for helping to reduce the rate, risk and incidence of chronic diseases like heart disease and cancer, Parkinson’s and Alzheimer’s, is due in part to its inclusion of olive leaves. 

In addition to its potent antioxidant effects, the oleuropein in OLE also combats bacteria and viruses, attacking and neutralizing them.

In addition, OLE may help cut down the length and degree of various infections, both chronic and acute, including:

  • Upper respiratory infections
  • Influenza and the common cold
  • Candidiasis
  • Shingles
  • Urinary tract infections
  • Mononucleosis
  • Rotavirus

OLE can also help to relieve symptoms related to viral and bacterial illnesses, like diarrhea and chronic fatigue.

High Blood Pressure; Olive Leaf Extract for Blood Pressure 

Hypertension is known as the silent killer because most sufferers don’t know they have it until it’s too late, and they have a heart attack or a stroke.

A 2011 study published in Phytomedicine called "Olive (Olea europaea) leaf extract effective in patients with stage-1 hypertension: Comparison with Captopril", researchers gave subjects with stage 1 hypertension a twice-daily dose of either OLE or the high-blood-pressure medication captopril.

After eight weeks, blood pressure had lowered significantly in both groups, demonstrating that OLE was as effective as captopril in achieving those results.

high blood pressure

In a 2017 study published in European Journal of Nutrition called "Impact of phenolic-rich olive leaf extract on blood pressure, plasma lipids and inflammatory markers: a randomised controlled trial", researchers gave either OLE or a placebo to 60 subjects with prehypertension for six weeks while monitoring their blood pressure throughout.

From the results, they concluded that OLE may lower both diastolic and systolic blood pressure, as well as cholesterol, triglycerides and inflammatory markers of high blood pressure.


In a 2018 review of medical research into the potential of the anti-inflammatory properties of OLE to benefit people with Alzheimer’s disease, studies in test tubes and on animals showed promising results. 

The study, "Benefit of Oleuropein Aglycone for Alzheimer's Disease by Promoting Autophagy" published in Oxidative Medicine and Cellular Longevity, found that OLE could reduce the harm that oxidative stress causes to the brain.

In a 2016 research review called "Olives and Bone: A Green Osteoporosis Prevention Option" published in the International Journal of Environmental Research and Public Health, researchers found that OLE might even stave off age-related bone loss by preventing fat from accumulating in the individuals' bone marrow.

Joints and Bones

joints & bones

Not exclusively a problem for the aging, issues of joint pain, chronic and otherwise, and conditions like osteoporosis and osteoarthritis may all benefit from OLE.

In a 2017 Nutrients review of research called "Therapeutic Effects of Olive and Its Derivatives on Osteoarthritis: From Bench to Bedside", osteoarthritis patients showed improvements after taking OLE.

The study also speaks to the autophagic property of OLE, which is its ability to clean out damaged cells and replace the area with fresh, newly generated healthy cells.

Type 2 Diabetes

olive leaf extract on diabetes
Studies of olive leaf extract’s effects on blood sugar have led researchers to conclude that it may be beneficial in both treating and preventing the illness.

In a review of "Functional foods in the treatment of type 2 diabetes: olive leaf extract, turmeric and fenugreek" published in Functional Foods in Health and Disease, researchers found that OLE could potentially improve the secretion of insulin in the body’s cells. 

The review detailed the findings of multiple animal studies including that OLE could help raise serum insulin levels and both lower and stabilize:

  • Cholesterol
  • Serum glucose
  • Blood glucose and plasma malondialdehyde levels and other indications of oxidative stress, in which an excess of free radicals causes damage to the body’s cells
  • Hyperglycemia, or high blood sugar
  • Hyperinsulinemia, or excessive insulin in the blood

A human study recounted in the review found that, while taking OLE didn’t significantly affect insulin levels, it may help reduce insulin resistance in the body, one of the main risk factors for the illness.

In the same human study, OLE did, however, lower fasting plasma insulin levels, as well as average blood sugar levels.

In a 2011 study, "Olive Leaf Extract as a Hypoglycemic Agent in Both Human Diabetic Subjects and in Rats" published in the Journal of Medicinal Food, Israeli researchers found that blood sugar levels in adult patients with type 2 diabetes who took OLE for 14 weeks decreased significantly more than other patients fed only a placebo for the same period. 

This study replicated an earlier animal study with comparable results.

Another study, this one published in the journal PLOS ONE in 2013 entitled "Olive (Olea europaea L.) Leaf Polyphenols Improve Insulin Sensitivity in Middle-Aged Overweight Men: A Randomized, Placebo-Controlled, Crossover Trial", found that, after taking either OLE or a placebo for 12 weeks, a group of 46 overweight middle-aged men, those taking the OLE experienced notable improvements in pancreatic responsiveness and insulin sensitivity, both significant factors in whether type 2 diabetes develops, versus those taking the placebo.
clinical studies on olive leaf

Alzheimer’s and Parkinson’s disease

olive leaf for alzheimer's & Parkinson's

According to a 2014 study published in the International Journal of Molecular Sciences entitled "Effects of the Olive-Derived Polyphenol Oleuropein on Human Health", the antioxidant properties of oleuropein may help protect against Alzheimer’s disease and prevent loss or damage of dopamine neurons related to Parkinson’s disease.

Olive Leaf Extract Herpes

In a 2016 study published in the African Journal of Microbiology Research, researchers found that the antimicrobial and antiviral properties in olive leaf extract impeded the herpes virus’ ability to invade the cells around it. (Source: Anti-HSV type-1 activity of olive leaves extract crude form acting as a microemulsion dosage form)

In addition, powerful anecdotal evidence exists supporting OLE's use to treat cold sores, although research has been restricted to cell cultures so far, and no human studies have verified this finding as yet. (Source: "The Effect of Hydroalcoholic Extract of Olive Leaves against Herpes Simplex Virus Type 1"; Iranian Journal of Medical Sciences)

To use olive leaf extract to treat herpes, place a cotton ball with one or two droplets of OLE on it onto the sore.
olive leaf for herpes


cancer pink ribbon
A 2009 cell study published in Molecular Nutrition and Food Research entitled Phytochemicals in olive-leaf extracts and their antiproliferative activity against cancer and endothelial cells" found olive leaf extract able to halt the growth and spread of cancer cells.

In a 2016 study published in the journal Nutrients entitled "Evidence to Support the Anti-Cancer Effect of Olive Leaf Extract and Future Directions", researchers found the anti-inflammatory and antioxidant properties of OLE able to combat the growth of several types of cancer cells, including:

  • Breast cancer
  • Prostate cancer
  • Pancreatic cancer
  • Colorectal cancer

Cardiovascular Health and Cholesterol

heart and cholesterol health
Olive leaf extract has undergone extensive studies into its potential benefits for atherosclerosis and other cardiovascular conditions associated with high levels of LDL cholesterol, on bad cholesterol.

In one 2015 animal study published in Phytotherapy Research called "Olive Leaf Extract Improves the Atherogenic Lipid Profile in Rats Fed a High Cholesterol Diet", the cholesterol levels in rats decreased after taking OLE for eight weeks. 

The study also found that OLE helped to restore the heart rates of rats with arrhythmia to normal.
A 2008 study on human subjects called, "Food supplementation with an olive (Olea europaea L.) leaf extract reduces blood pressure in borderline hypertensive monozygotic twins" published in the same journal looked at 40 identical twins, all of whom had high blood pressure. The researchers divided the pairs into two groups and, for eight weeks, gave one group OLE and the other group food supplementation. 

At the end of the study, they discovered that the OLE decreased LDL cholesterol levels in both pairs of twins in the group receiving it. What's more, they discovered that the larger the dose they administered, the more it lowered those levels.

By helping prevent LDL cholesterol buildup in your arteries, OLE can help increase the flow of blood and reduce heart disease risk.

Weight Management

In a 2014 animal study published in Evidence-Based Complementary and Alternative Medicine called "Olive Leaf Extract Attenuates Obesity in High-Fat Diet-Fed Mice by Modulating the Expression of Molecules Involved in Adipogenesis and Thermogenesis", OLE affected particular genes in the body involved in its natural formation and burning up of fat cells, thereby helping to prevent obesity related to a high-fat, high-cholesterol diet. 

OLE may also help lower appetite and increase the sensation of fullness, thereby helping to reduce overeating.

In a similar study, published in Science Direct in 2018 and called, "Evaluation of hypocholesterolemic effect of oleuropein in cholesterol-fed rats", obese rats fed a high-cholesterol diet experienced a reduction in fatty tissue, metabolic profile improvements and lower overall body weight after being administered oleuropein for eight weeks.

losing weight with olive leaf
There is also evidence from one study, from Food Science and Technology Research, called "Identification of Anti-α-Amylase Components from Olive Leaf Extracts" that yielded evidence supporting the conclusion that OLE may help inhibit carbohydrate absorption, thereby also potentially moderating weight. 

Specifically, the researchers found: "1g of olive leaves taken alongside 300g of rice was able to decrease the subsequent glucose AUC from the meal in persons with borderline glucose levels, but not in fully healthy persons." 

As studies reported in 2004 in Alternative Medicine Review from a clinical trial entitled Blocking carbohydrate absorption and weight loss: a clinical trial using Phase 2 brand proprietary fractionated white bean extract" reveal, blocking carbohydrate absorption may, indeed, promote weight loss. 

While this particular study was not conducted using OLE per se, the effects of the carbohydrate-absorption-inhibitor utilized, that being white bean extract, in particular, can be reasonably extrapolated to correlate. (Source: "Olive Leaf Extract"; Examine.com)

While more human studies on OLE for weight loss are still warranted, these studies on rats have at least led researchers to conclude already that OLE can help to prevent unwanted weight gain and, thereby, lower obesity risk.

Olive Leaf Extract Dosage

olive leaf extract dosage

Once you know that you'd like to try taking OLE, the next questions are: how much to take and where to obtain it?

Olive leaf extract comes in several forms, including:

  • Supplement - In which the OLE is dried and powdered and delivered in a tablet, softgel or capsule form
  • Tincture - In which the OLE is infused into an alcohol or glycerin
  • Tea - In which the OLE is steeped in hot water

While no official dosing recommendations exist, WebMD reports that studies find daily doses of 500-1,000 mg of OLE appropriate.

On the label of many OLE supplements, you’ll read the recommendation to split this dosage into between two and four servings spread out throughout the day and taken with food.

olive leaf tea

That said, specific dosing most appropriate for men, women or children is not currently available and, for that reason, you should consult with your doctor if you'd like more guidance about precisely how much OLE is right for you. Your doctor can even monitor you while you're taking it to help assess its effects.

OLE for Pregnant Women

olive leaf extract dosage for pregnant women

There is currently a lack of sufficient data to conclude whether or not OLE is safe or effective for pregnant or breastfeeding women.

Olive Leaf Extract Side Effects

olive leaf extract side effects

The relatively small amount of research into OLE to date leaves little known about the potential side effects from taking it.

One of the most severe known potential side effects of olive leaf extract is an allergic reaction affecting the respiratory system, particularly in people who are allergic to pollen, and of those, particularly those allergic to the pollen from the Oleaceae family of plants that also includes privets, forsythia, jasmine, lilacs and ash trees. (Source: ”Natural Standard Herb & Supplement Guide - E-Book: An Evidence-Based Reference”; Natural Standard)

Drug Interactions

If you have diabetes or take any blood thinners or blood pressure medications, consult with your doctor before trying OLE. When taking blood pressure medication in particular, olive leaf extract can bring your blood pressure down too low.

Similarly, those taking blood sugar medications or insulin should be cautious using olive leaf extract, as it can bring on hypoglycemia. If you are taking chemotherapy drugs, the antioxidant properties in OLE can interfere with the treatment’s actions.

Also consult with your doctor before taking OLE if you have kidney disease.

While mild, other potential side effects of OLE include:

  • Discomfort
  • Headaches
  • Stomach pains
  • Coughing
  • Vertigo
olive leaf extract drug interaction

While the US Food and Drug Administration (FDA) doesn’t regulate OLE or any other nutritional supplements, its centuries-long history of use by people from thriving Mediterranean cultures may give you some comfort as to its relative safety.

That said, if you experience any concerning or severe side effects while taking OLE, certainly cease taking it until you at least first speak with a doctor.

Where to buy OLE

where to buy olive leaf extract

Keep in mind that supplements are not regulated by the FDA or any other US government body for product safety.

Therefore, for quality assurance when choosing a brand of olive leaf extract supplements, seek out those products manufactured on a SQF certified facility regulated by the FDA

When storing olive leaf extract, keep it in a dark, cool space, like the kitchen cabinet.  And keep the capsules store in its original bottle to maximize its lifespan.  

You can find OLE for sale in health food stores and online.


olive leaf extract summary

Olive leaf extract has many possible benefits, including some that may help you. Before you try OLE for any conditions or symptoms you experience, let your doctor know what you’re planning first, in case he or she wants to monitor you or check your medical history and medication list for any contraindications.

Beyond that, keep in mind that, as with any herbal therapy, the results from OLE can be subtle, especially at first, and gradual, building up in their efficacy over time.

Don’t consider OLE a possible replacement for any therapies you’re already taking or doing under a doctor’s recommendation, but rather as a supplement, to help it all work better and increase your likelihood of experiencing the results you’re seeking faster and more fully.

ole herbal therapy

Other References:

About the author

A software engineer, former IBMer, co-founder of Naravis Corporation and a mom, with a passion for finding the solution and root cause to everything that comes across, including health. It has been a long journey since founding Naravis and trying to find solutions to my leaky gut syndrome and pursue natural health. Throughout this journey I have learned an enormous amount of information (acquired knowledge) and I feel it's my duty to share my knowledge and my experience with you.

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