The olive leaf is a staple of the Mediterranean diet, which scientists study for its potential to prevent chronic diseases. Research points to lower rates of illnesses and cancer-related deaths among populations that follow this diet. The positive effect is due in part to the powerful and health-boosting benefits of the olive leaf.
Olive leaf extract is a concentrated dose of the nutrients in olive tree leaves. It’s a potent source of antioxidants that support your immune system.
By fighting cell damage that causes disease, antioxidants work to reduce your risk of many illnesses — but research shows that this activity in olive leaf extract may contribute to a range of other health benefits.
The antioxidants in olive leaf extract are mainly polyphenols. Scientists believe these plant-based nutrients play a role in preventing conditions like cognitive decline, cancer, and osteoporosis.
Olive leaf also contains a uniquely powerful polyphenol called oleuropein. Studies show that in addition to its antioxidant activity, oleuropein has anti-inflammatory, antiviral, and antimicrobial effects. These properties point to research-backed health benefits like:
Improved Cardiovascular Health
Research shows that olive leaf extract helps prevent LDL (bad) cholesterol from building up in your arteries. This effect helps increase blood flow and lower blood pressure, reducing your risk of heart disease.
A study using rats also points to olive leaf extract’s effectiveness in helping restore a normal heartbeat in those with arrhythmia, although further research with human subjects would be more conclusive.
Lower Risk of Diabetes
The antioxidants in olive leaves can lower your blood sugar and help stabilize it to maintain healthy levels. Researchers find that this effect helps treat people with diabetes and may prevent you from developing the disease.
Studies also show that olive leaf extract can reduce your body’s insulin resistance, one of the biggest risk factors for diabetes.
Stronger Immune System
The Mediterranean diet is associated with a lower rate of chronic diseases — including cancer, heart disease, Parkinson’s, and Alzheimer’s. Olive leaf extract supports this trend thanks to oleuropein’s ability to attack and neutralize viruses and bacteria.
Some studies indicate oleuropein may stop cancer cell growth. Olive leaf extract may also reduce the severity and duration of upper respiratory infections.
More research is needed in humans, but early studies show that the oleuropein in olive leaf extract prevents unwanted weight gain and reduces the risk of obesity.
In laboratory tests, oleuropein lowered body fat and weight gain in animals fed high-cholesterol and high-fat diets. It also reduced food intake, suggesting olive leaf extract can also help manage appetite and overeating.
Agencies like the Food and Drug Administration don’t regulate nutritional supplements like olive leaf extract. But because olive leaves have been an important part of the Mediterranean diet for centuries, the extract is considered safe for most people.
If you are managing a health condition or taking prescription medication, make sure to talk to your doctor before taking olive leaf extract. Issues that olive leaf extract may cause include:
Mild Side Effects
Some studies report side effects — including coughing, vertigo, stomach pains, and headaches.
Some people are allergic to the pollen produced by olive trees and may have an allergic reaction when taking olive leaf extract.
Olive leaf extract may lower your blood pressure and blood sugar levels. If you have diabetes or are taking medications to manage your blood sugar or blood pressure, talk to your doctor before taking olive leaf extract.
People with kidney disease should consult with their doctor before taking it, as well.
Possible Interactions With Pregnancy
Not enough data is available to suggest olive leaf extract is safe for pregnant or breastfeeding women.
Amounts and Dosage
You can buy olive leaf extract as a supplement, tincture, or tea. There are no official dosing recommendation, but studies indicate its health-boosting effects occur when taking 500 to 1,000 milligrams daily.
Because formulations and products can vary, follow your doctor’s recommendation and manufacturer’s guidelines to ensure you take a safe but effective amount.