What Is Banaba Leaf and How Does It Work?

Banaba leaf comes from the banaba tree, known by its botanical name Lagerstroemia speciosa. The tree grows in India, Southeast Asia and the Philippines. Its leaves contain natural plant compounds, including corosolic acid and ellagitannins. Researchers have studied these compounds for their possible role in supporting healthy blood sugar levels. Banaba leaf is used in herbal teas and in supplements designed to support metabolic health.

What Is Banaba Leaf?

Banaba is a tree in the Lythraceae family. It is also known as giant crape myrtle, queen’s crape myrtle and Pride of India. In parts of India, it is called jarul. Banaba leaves are used dried, as a powder, in tea and in extracts made for supplements.

Where the Banaba Tree Grows

Banaba is a tropical tree that can grow up to 20 metres tall. It sheds some of its leaves during the dry season. The tree grows in India, Southeast Asia and the Philippines. It is also planted along roads and in parks because of its pink and purple flowers. Its leaves are large and oval. Researchers and supplement makers use the dried leaves.

Traditional Use of Banaba Leaves

In the Philippines, people have brewed banaba leaves as tea for many generations. Traditional medicine in parts of Southeast Asia also used the leaves for high blood sugar. People drank banaba tea for other reasons, including to increase urination. One early laboratory study on banaba was published in 1940. In that study, Garcia reported that banaba leaf tea lowered blood sugar in rabbits. Many later human studies were carried out in Japan and the United States.

What Compounds Are in Banaba Leaf?

Banaba leaf contains several plant compounds. Research has focused on two groups: corosolic acid and ellagitannins. The leaf also contains ellagic acid, oleanolic acid, quercetin and plant sterols.

Corosolic Acid

Corosolic acid is a natural compound found in banaba leaves. It is used as a marker to measure the strength of banaba extracts. Laboratories test the amount of corosolic acid in an extract to help maintain consistent quality. Some early laboratory studies suggest that corosolic acid may help glucose move from the blood into cells. Research has also explored its possible effects on blood sugar after meals and blood fat levels.

Ellagitannins and Other Tannins

Ellagitannins are plant compounds that dissolve in water. One of these compounds, lagerstroemin, showed effects similar to insulin in laboratory tests. Corosolic acid does not dissolve easily in water, but water-based banaba leaf extracts may still affect how the body handles glucose. Researchers believe ellagitannins may help explain this effect. Tannins make up a large part of the leaf. In one laboratory test, tannins made up about 37% of the dry weight of a water-based extract.

How Does Banaba Leaf Work?

Researchers have studied several ways banaba leaf may affect blood sugar. Much of this research has been carried out in cells and animals. Scientists are still studying whether the same effects occur in people.

How Glucose Enters Cells

Glucose is a type of sugar that the body uses for energy. GLUT4 is a protein that helps move glucose from the blood into muscle and fat cells. In a study on mice, corosolic acid increased GLUT4 levels in muscle. Laboratory tests have also found that banaba leaf extracts may help fat cells take in more glucose. These findings are one reason researchers have studied whether corosolic acid has effects similar to insulin.

Slower Breakdown of Carbohydrates

The body uses enzymes called alpha-glucosidase and alpha-amylase to break down carbohydrates into simple sugars, including glucose. Some laboratory studies suggest that compounds found in banaba leaf may slow this process. This could help reduce the rise in blood sugar after a meal. Animal studies have also found that corosolic acid may reduce the amount of glucose made by the liver. More research is needed to understand how these effects work in people.

Banaba Leaf Benefits Reported in Research

Human studies on banaba leaf are small and short. The examples below are reported in a 2012 review by Miura, Takagi and Ishida, published in Evidence-Based Complementary and Alternative Medicine. These findings are preliminary and do not prove that banaba leaf will have the same effects in everyone.

Blood Sugar Support

·       Judy et al. (2003): Ten adults with type 2 diabetes took 32 mg or 48 mg a day of a banaba leaf extract standardised to 1% corosolic acid. After two weeks, blood glucose was about 30% lower in the soft gel group.

·       Ikeda et al. (2002): Fifteen adults took 100 mg a day of a water-soluble banaba leaf extract for one year. Fasting glucose fell by 16.6% among participants whose starting level was above 110 mg/dL. No participants had low blood sugar during the study.

·       Fukushima et al. (2006): Thirty-one adults took either 10 mg of corosolic acid or a placebo before drinking 75 g of glucose. Neither the participants nor the researchers knew who received which option. Blood glucose was lower from 60 to 120 minutes after the drink, with a significant difference at 90 minutes.

·       Tsuchibe et al. (2006): Twelve adults without diabetes took 10 mg of corosolic acid a day for two weeks. Fasting and after-meal glucose both fell by about 12%.

Weight Management

Only a few studies have examined banaba leaf and weight loss. In one 12-week programme, 56 adults followed a diet and exercise plan and took a supplement containing banaba and other ingredients. They lost an average of 6.29 kg. Because the supplement contained several ingredients and the programme also changed diet and exercise, the study cannot show how much of the weight loss came from banaba. In the Tsuchibe study, participants lost about 1.4 kg in two weeks. In mice fed a high-cholesterol diet for 10 weeks, corosolic acid lowered blood cholesterol by 32% and liver cholesterol by 46%. These results do not establish that banaba leaf causes weight loss in people.

Antioxidant Activity

Laboratory studies suggest that banaba leaf extract may help neutralise free radicals, which are unstable molecules that can damage cells. The extract also reduced damage to fats inside cells in laboratory tests. In diabetic mice, it increased the activity of the body’s own antioxidant enzymes. These findings come mainly from laboratory and animal studies. There is still little human research on this possible effect.

Overall, many banaba trials have been small, short or open-label, meaning that participants knew what they were taking. Drugs.com notes that there is not enough clinical trial evidence to recommend banaba for any condition. Larger and longer studies are needed.

Why Supplement Brands Use Banaba Leaf

Interest in products for blood sugar and weight management has grown, partly because of public attention on GLP-1 medicines. Supplement brands often look for plant ingredients with a history of traditional use, research in people and a compound that laboratories can measure. Banaba leaf has these features, although the available research is still limited.

Some studies have tested low daily amounts, such as 10 mg of corosolic acid. Banaba extracts can be used in capsules, tablets, gummies and drink mixes alongside other ingredients. Brands may combine banaba extract with other botanicals studied for metabolic health, such as berberine and salacia. Chromium and cinnamon are also used in some products.

The amount of corosolic acid can vary from one leaf harvest to another. For this reason, supplement brands may look for extracts that are standardised and tested using HPLC, a laboratory method for measuring compounds in a mixture. A certificate of analysis can provide test results for each batch. Ingex Botanicals tests its botanical extracts against set quality standards.

Frequently Asked Questions

What Is Banaba Leaf Used For?

Banaba leaf is mainly used in supplements designed to support healthy blood sugar and metabolic health. It is also used in some weight management products and herbal teas. In the Philippines, people have brewed banaba leaf tea for generations.

What Is Corosolic Acid?

Corosolic acid is a natural compound found in banaba leaves. It is used as a marker to measure the strength of banaba extracts. Some studies suggest that it may help cells take in glucose and may slow the breakdown of carbohydrates. More research is needed to confirm its effects in people.

Is Banaba the Same as Crape Myrtle?

Banaba is one type of crape myrtle. Its botanical name is Lagerstroemia speciosa, and it is also called giant crape myrtle or queen’s crape myrtle. The common garden crape myrtle, Lagerstroemia indica, is a different species.

Does Banaba Leaf Help With Weight Loss?

A few small studies have reported weight loss among people taking supplements that contain banaba. Most of these studies also included other ingredients, diet changes or exercise. The effect of banaba leaf on its own is not clear. Most banaba research has focused on blood sugar.

Can Banaba Leaf Be Taken With Metformin?

Banaba leaf may lower blood sugar. Taking it with metformin or other diabetes medicines could lower blood sugar further. People who take diabetes medicine should speak with a doctor before using banaba leaf supplements.

What Is the Difference Between Banaba Leaf and Banaba Extract?

Banaba leaf is the dried leaf, which can be used whole, as a powder or in tea. Banaba extract is a concentrated form made by drawing compounds out of the leaf. It can be adjusted to contain a set amount of corosolic acid. This helps make the amount of corosolic acid more consistent from one dose to another.

What Is Banaba Leaf? A Short Summary

Banaba leaf comes from the Lagerstroemia speciosa tree, which grows in India, Southeast Asia and the Philippines. Its main compounds, corosolic acid and ellagitannins, have been studied for their possible role in blood sugar support. Research includes laboratory tests, animal studies and a small number of human studies. Banaba leaf has a long history of use as a tea, and corosolic acid can be measured in laboratory tests. These features make banaba leaf relevant to some metabolic health supplements. Brands can request a banaba sample from Ingex Botanicals through its contact page.