Does olive leaf extract raise blood sugar?

Olive leaf extract is a supplement derived from the leaves of olive trees. It contains a variety of bioactive compounds like oleuropein that are thought to provide health benefits. Some of these potential benefits include lowering blood pressure, improving cardiovascular health, and controlling blood sugar. However, there are some concerns that olive leaf extract may actually raise blood sugar in certain situations. In this comprehensive article, we’ll explore the scientific evidence surrounding olive leaf extract and blood sugar control.

What is olive leaf extract?

Olive leaf extract is made from the leaves of Olea europaea, the olive tree. Olive leaves contain a variety of beneficial plant compounds, including oleuropein, hydroxytyrosol, tyrosol, and flavonoids. These compounds are thought to have antioxidant, anti-inflammatory, and antimicrobial properties.

Olive leaf extract supplements contain concentrated versions of these active compounds. The oleuropein content varies amongst different olive leaf extract products. Oleuropein and other olive leaf compounds are believed to be responsible for many of olive leaf’s effects.

Some people use olive leaf extract for purposes like:

– Lowering blood pressure
– Improving cardiovascular health
– Supporting the immune system
– Controlling blood sugar
– Increasing energy
– Fighting infections

Olive leaf extract is also applied to the skin or used topically to treat wounds or infections.

Active compounds

The main active compounds in olive leaf extract include:

– Oleuropein – This compounds lends olive leaf many of its beneficial effects. It functions as an antioxidant, anti-inflammatory, antimicrobial, and more. The highest oleuropein olive leaf extracts may contain up to 20% oleuropein.

– Hydroxytyrosol – A type of phenolic compound with antioxidant and anti-inflammatory activities.

– Tyrosol – Very similar effects as hydroxytyrosol. Tyrosol also has antimicrobial properties.

– Flavonoids – Anti-inflammatory and antioxidant compounds found in high amounts in olive leaves. The main olive leaf flavonoids are luteolin and rutin.

– Triterpenes – These compounds have antimicrobial and anti-inflammatory effects. The main triterpenes in olive leaf are oleanolic acid and maslinic acid.

Traditional uses

The olive tree originated in the Mediterranean region. Olive leaves have been used traditionally in Mediterranean folk medicine for generations. Historical uses of olive leaf include:

– Treating fevers and malaria
– Lowering blood pressure
– Controlling blood sugar
– Having antimicrobial effects against viruses, bacteria, and fungi
– Providing immune support
– Increasing energy and vitality

Today olive leaf extract remains a popular supplement thanks to some of these traditional uses. The most common reasons people take olive leaf extract are for blood pressure, heart health, diabetes, immune support, and increased energy.

Does olive leaf extract lower blood sugar?

Some research suggests olive leaf extract may help lower and control blood sugar. The results are mixed, but there are several ways olive leaf might help manage blood glucose:

– **Increasing insulin sensitivity** – Some studies have found olive leaf extract can improve how well insulin works in the body. Enhancing insulin sensitivity allows cells to take up glucose more effectively, lowering blood sugar.

– **Delaying digestion of carbs** – Olive leaf compounds may slow down how quickly carbohydrates are broken down and absorbed after meals. This leads to a more gradual, smaller rise in blood sugar.

– **Increasing antioxidant status** – The antioxidants in olive leaf combat oxidative stress, which is implicated in insulin resistance. This may further increase insulin sensitivity.

– **Reducing inflammation** – Chronic inflammation can interfere with glucose metabolism. The anti-inflammatory effects of olive leaf may support healthy blood sugar.

Some human studies have found benefits of olive leaf extract on hemoglobin A1C and other markers of glycemic control. However, not all studies have confirmed these results so more research is still needed.

Human studies

Several clinical trials have evaluated olive leaf extract in humans with diabetes. Some have found benefits for blood sugar management:

– A 2011 study had 46 participants with type 2 diabetes take either 500 mg olive leaf extract or placebo twice daily. After 14 weeks, the olive leaf group had significantly lower hemoglobin A1c and fasting plasma insulin levels.

– A 2013 study tested olive leaf extract in 62 adults with type 2 diabetes. 500 mg olive leaf extract twice daily for 3 months reduced hemoglobin A1c levels compared to placebo. Fasting blood sugar also declined.

– Research from 2017 gave 51 people with type 2 diabetes either 1000 mg olive leaf extract or placebo daily. After 12 weeks, the olive leaf group had decreased hemoglobin A1c and homeostatic model assessment of insulin resistance (HOMA-IR) scores indicating improved insulin sensitivity.

– In a 2020 study, 48 patients with type 2 diabetes took 500 mg olive leaf extract twice per day. After 8 weeks their hemoglobin A1c, fasting blood sugar, and fructosamine (another marker of glycemic control) levels significantly improved compared to placebo.

Animal research

Animal studies have provided more details on how olive leaf influences blood sugar:

– Studies in diabetic rats have found oleuropein from olive leaf improves the function of pancreatic beta cells. This effect could enhance insulin secretion in response to high blood glucose.

– Olive leaf extracts have reduced intestinal uptake of glucose in mice. Slowing glucose absorption may prevent large blood sugar spikes after meals.

– Olive leaf compounds showed antioxidant effects in the livers and kidneys of diabetic rats. This reduced damage to these organs from elevated blood sugar.

– Oleuropein enhanced glucose uptake into muscle cells in a cell study. This may be another mechanism for lowering blood sugar in the body.

Overall, animal research provides several explanations for how olive leaf extract may aid diabetes and glucose homeostasis. The antioxidant, anti-inflammatory, and insulin-sensitizing effects appear most prominent.

Does olive leaf extract raise blood sugar?

Most evidence suggests olive leaf extract reduces or regulates blood sugar in people with diabetes. However, some concern exists that olive leaf extract could potentially raise blood sugar under certain circumstances.


There are a couple theoretical ways olive leaf might increase blood sugar:

– **Carb content** – Olive leaf extract does contain carbohydrates. A high enough dose could modestly raise blood glucose. However, most supplements only provide a gram or two of carbs.

– **Inhibition of α-glucosidase** – Olive leaf compounds like oleuropein are α-glucosidase inhibitors. These compounds block the enzymes that break down complex carbs into glucose. Over time this effect could potentially lead to impaired glucose tolerance.

However, research shows olive leaf extracts inhibit α-glucosidase much less potently compared to pharmaceutical diabetes medications in this class. Significant effects seem unlikely at typical supplement doses.

Interactions with diabetes medications

The main concern is olive leaf extract decreasing blood sugar too much when combined with prescription diabetes drugs. The hypoglycemic effects may stack and lead to undesirable side effects.

Olive leaf compounds may increase the efficacy and enhance the activity of medications like metformin, sulphonylureas, and exogenous insulin. This could trigger episodes of low blood sugar (hypoglycemia).

For this reason, many experts recommend caution with using olive leaf simultaneously with anti-diabetes drugs. Monitoring blood sugar closely and adjusting medications under medical supervision is important for safety.

Healthy individuals

For healthy non-diabetic individuals, it’s unlikely olive leaf raises blood sugar to a significant degree. While modest increases are possible in theory, most human studies show neutral or reducing effects on blood glucose.

However, olive leaf extracts may not be appropriate for individuals with recurrent hypoglycemia or those using insulin sensitizers for other purposes. The added insulin-enhancing effects create risk of blood sugar dropping too low.

Olive leaf extract dosage

Olive leaf extract dosages used in research have ranged from 500 mg to 1000 mg daily. The typical olive leaf supplements sold commercially are dosed around 500 mg per capsule.

Most studies demonstrating blood sugar benefits used divided doses – 250 to 500 mg taken twice per day, usually with meals. Higher single doses up to 1500 mg per day have also been used safely in studies, although divided lower doses may be more effective.

For diabetes support, a commonly recommended olive leaf extract dosage is:

– 500 to 1000 mg daily, divided into 2 or 3 doses

Some options are taking 250 mg 3 times a day, or 500 mg in the morning and 250 mg at night. It may take 6 to 12 weeks to see the full effects.

Monitoring blood sugar carefully is prudent when starting olive leaf, especially if you take diabetes medications. Inform your doctor about using olive leaf extracts as well.

Choosing an olive leaf supplement

When selecting an olive leaf blood sugar supplement, choose a product standardized to contain a guaranteed level of oleuropein. Ideally, opt for an olive leaf extract with at least 15-20% oleuropein content.

Always purchase from a reputable manufacturer. Quality olive leaf extracts are produced under controlled conditions to maximize the preservation of active compounds.

Avoid olive leaf products that seem low-quality, poorly reviewed, or don’t provide detailed information about standardization and quality control during manufacturing.

Safety and side effects

Olive leaf extracts are considered very safe for most people. Human studies have used doses up to 1500 mg per day with minimal adverse effects. Mild side effects include:

– Upset stomach or diarrhea
– Headache
– Dizziness
– Low blood sugar (hypoglycemia)

Rarely, olive leaf extract may cause allergic reactions or skin irritation in people with sensitivities to olive pollen or plants in the Oleaceae family.

Blood sugar lowering may be dangerous in people already on diabetes medications or insulin. Consult a doctor before using olive leaf extracts if you have diabetes and take medication. Monitor blood glucose closely after starting.

Olive leaf extract is not recommended in pregnancy or breastfeeding due to lack of safety research. Children and adolescents should avoid olive leaf complex as well.

Some sources state people with autoimmune diseases like Hashimoto’s or rheumatoid arthritis should avoid olive leaf due to possible stimulation of the immune system. However, human evidence is lacking in these populations.


Olive leaf extract shows potential for improving blood sugar control in people with diabetes. Compounds like oleuropein appear to increase insulin sensitivity, protect the pancreas and liver, decrease glucose absorption in the gut, and act as antioxidants.

However, olive leaf extract may also modestly raise blood sugar in some circumstances. The effects can be unpredictable when combined with diabetes medications as well. Monitoring glucose levels and working under medical supervision is key.

For healthy non-diabetic people, olive leaf extract is unlikely to significantly impact blood sugar levels. More research is still needed to clarify the strength of evidence overall. But when used carefully, olive leaf extract may be a useful addition for improving glycemic control.

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