Olive leaf extract: what it may do and how to choose a supplement
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- Olive leaf extract, 500 mg capsules. Best for: Adults who want the dose most often used in trials. See options on Amazon
- Higher-oleuropein olive leaf extract. Best for: Buyers comparing standardized extracts. See options on Amazon
- Olive leaf extract liquid. Best for: People who prefer drops to capsules. See options on Amazon
What olive leaf extract is
Olive leaf extract (Olea europaea) is made from the leaves of the olive tree. Memorial Sloan Kettering Cancer Center (MSK) says olive leaves and extracts have been used for infections, inflammation, diabetes and high blood pressure.
A major compound in the leaf, oleuropein, has antioxidant and anti-inflammatory activity in lab studies. MSK notes that animal studies found the whole extract worked better than pure oleuropein at lowering cholesterol, suggesting other leaf compounds also play a role.
What the research shows
| Study | What it found |
|---|---|
| 2022 meta-analysis, 12 trials, 819 adults | Lower triglycerides and systolic blood pressure; no change in blood sugar, liver, kidney or inflammation markers |
| 2021 meta-analysis, 5 trials, 325 adults with high or borderline blood pressure | 500 mg a day lowered systolic pressure; 1,000 mg a day did no better than placebo |
| 2021 trial, 77 overweight adults, 8 weeks | 500 mg a day did not change cholesterol, blood pressure or blood sugar |
Blood pressure and lipids. The 2022 meta-analysis in Diabetology and Metabolic Syndrome found average drops of about 9.5 mg/dl in triglycerides and 3.9 mmHg in systolic blood pressure. In people with high blood pressure, systolic pressure dropped about 4.8 mmHg and total and LDL cholesterol also fell. The authors called the evidence for blood sugar, liver, kidney and inflammatory markers low to very low quality.
Mixed results. A 2021 PeerJ meta-analysis found 500 mg a day for at least 8 weeks lowered systolic pressure by about 5.8 mmHg versus placebo, but warned the small number of participants limits firm conclusions. A 2021 trial in the European Journal of Nutrition found no significant changes after 8 weeks of 500 mg a day in overweight adults with mildly high cholesterol.
Infections and immunity. Olive leaf is widely marketed for immune support. MSK lists lab findings against bacteria and fungi, and one study of a cream for cold sores, but not proof that swallowing capsules prevents infections.
Safety and interactions
- Blood pressure medicine. MSK notes olive leaf lowered blood pressure in rats and may add to blood pressure drugs. Check your readings and ask your provider.
- Diabetes medicine. Lab and animal studies suggest it lowers blood sugar, so it may add to insulin or other diabetes drugs.
- Pollen allergy. Olive tree pollen may cause severe respiratory allergy. If you react to olive pollen, ask your provider before using leaf products.
- Pregnancy and nursing. NOW Foods advises consulting a physician if pregnant or nursing, taking medication or managing a medical condition.
- Not a treatment. Do not stop or replace blood pressure, cholesterol or diabetes medicine.
Reading an olive leaf extract label
- Extract amount. Studies most often used 500 mg a day, with some using 1,000 mg. NOW Foods' Olive Leaf Extract gives 500 mg per capsule, taken 1 to 3 times daily as needed.
- Oleuropein percentage. Labels list how much oleuropein the extract is standardized to; NOW Foods' is at least 6%. Higher percentages are sold, but trials have not shown that a higher percentage works better.
- Ratio claims. High extract ratios do not tell you how a product compares with studied extracts.
- Blends. Immune formulas often add oregano oil, garlic or other herbs, which brings their own cautions.
- Testing. Prefer brands that state third-party testing.
Who may want to talk with a provider first
If you have high blood pressure, high cholesterol or diabetes, ask your provider whether olive leaf extract fits your plan and how to monitor it. The blood pressure changes in trials were modest and not seen in every study, so keep taking any medicine as prescribed and keep checking your readings.
What to look for when you buy
Olive leaf extract, 500 mg capsules
Best for: Adults who want the dose most often used in trials
NOW Foods lists 500 mg of olive leaf extract standardized to at least 6% oleuropein per capsule, the daily amount used in several studies.
Watch out: Benefits are modest and mixed. Ask your provider if you take blood pressure or diabetes medicine.
See options on AmazonHigher-oleuropein olive leaf extract
Best for: Buyers comparing standardized extracts
Many brands list a higher oleuropein percentage on the label, which tells you how the extract was standardized.
Watch out: A higher percentage has not been shown to work better. Do not exceed the label.
See options on AmazonOlive leaf extract liquid
Best for: People who prefer drops to capsules
Liquid extracts let you take olive leaf in water.
Watch out: Strength is harder to compare with studied capsule doses. Same medicine cautions.
See options on AmazonQuestions people ask
- What is olive leaf extract good for?
- Trials suggest modest drops in systolic blood pressure and triglycerides, mainly in people with high blood pressure. Evidence for immunity and blood sugar is weak.
- Does olive leaf extract lower blood pressure?
- A 2022 meta-analysis found an average drop of about 3.9 mmHg systolic, with larger effects in people with hypertension. Some trials found no effect.
- How much olive leaf extract should I take?
- Follow the label. Studies most often used 500 mg a day; NOW Foods directs 1 capsule 1 to 3 times daily.
- Can I take olive leaf extract with blood pressure medicine?
- Only with your provider's okay. It may add to the effect of blood pressure drugs.
- What is oleuropein?
- It is a major compound in olive leaves with antioxidant and anti-inflammatory activity in lab studies, often used to standardize extracts.
Sources
- The effects of olive leaf extract on cardiovascular risk factors in the general adult population: a systematic review and meta-analysis of randomized controlled trials (pmc.ncbi.nlm.nih.gov), Diabetology and Metabolic Syndrome (PMC9585795)
- Olive leaf extract effect on cardiometabolic profile among adults with prehypertension and hypertension: a systematic review and meta-analysis (pmc.ncbi.nlm.nih.gov), PeerJ (PMC8035902)
- The effect of olive leaf extract on cardiovascular health markers: a randomized placebo-controlled clinical trial (pmc.ncbi.nlm.nih.gov), European Journal of Nutrition (PMC8137474)
- Olive Leaf: About Herbs (mskcc.org), Memorial Sloan Kettering Cancer Center
- Olive Leaf Extract 500 mg Veg Capsules (www.nowfoods.com/products/supplements/olive-leaf-extract-500-mg-veg-capsules), NOW Foods