Banaba leaf and corosolic acid: how much is in supplements?

Most banaba supplements do not tell you how much corosolic acid they contain. Where a label does, the number can be tiny: one blood sugar capsule we reviewed lists 25 mg of banaba leaf extract standardized to 1% corosolic acid, which works out to about 0.25 mg of the compound. Trials have used extract doses of 32 to 48 mg a day, or 500 mg of banaba twice a day.

This guide explains what corosolic acid is, what the human studies used, how real labels in our reviews compare and what to look for before you buy. It describes research and labels, and is not medical advice.

What is banaba, and what is corosolic acid?

Banaba is the leaf of Lagerstroemia speciosa, a plant used for many years in folk medicine for diabetes. A 2012 review in Phytotherapy Research says the first published research on banaba dates to 1940, and that its blood sugar effects have been attributed to both corosolic acid and ellagitannins. The review also notes that the studies used three different materials: water-soluble leaf extracts, corosolic-acid-standardized extracts, and purified corosolic acid.

That last point is the key to reading a label. Corosolic acid is one compound in the leaf. A capsule can contain plain leaf powder, a leaf extract with no stated corosolic acid content, or an extract standardized to a percentage of it. Those are three different products even when all three say "banaba" on the front.

How much banaba did human studies use?

We opened three human-study sources on PubMed, and they sit at very different scales:

• A 2003 randomized trial in the Journal of Ethnopharmacology tested an extract of banaba leaves standardized to 1% corosolic acid, called Glucosol, in people with type 2 diabetes. Daily doses of 32 and 48 mg for 2 weeks were reported to significantly reduce blood glucose. The abstract also reports a 30% drop with a soft gel formulation versus 20% with a dry-powder hard capsule, which suggests the capsule type can matter.
• A 2022 placebo-controlled trial in the Journal of Medicinal Food gave 12 people with metabolic syndrome 500 mg of banaba twice a day for 12 weeks, while 12 others took placebo. The banaba group had lower fasting glucose (5.9 to 5.7 mmol/L), triglycerides and systolic blood pressure. It was a very small trial, and the abstract does not state a standardization.
• A 2023 trial in the International Journal of Women's Health tested DLBS3233, a bioactive fraction of banaba and a cinnamon species, in 60 women with polycystic ovary syndrome. It found no significant efficacy, either alone or with metformin. It is a different product from a leaf capsule, but it shows that results are not uniform.

A 2025 narrative review of banaba and chromium picolinate in prediabetes calls the early clinical results promising, but also notes that only one study had evaluated the combination and that further research is needed. The U.S. National Center for Complementary and Integrative Health says in its diabetes supplement overview that there is no reliable evidence that any herbal supplement can help control diabetes or its complications.

Putting those numbers side by side shows the problem with comparing products. A 32 to 48 mg dose of a 1% extract delivers roughly 0.3 to 0.5 mg of corosolic acid by simple arithmetic, while 1,000 mg a day of banaba in the metabolic syndrome trial is a much larger amount of material of unstated strength. Neither number tells you what a given capsule offers unless the label states the form, the amount and the standardization.

What do banaba amounts on real labels look like?

Here is what our reviews recorded for banaba in several ClickBank offers:

Offer	Banaba on the label	What the review says
RegenVive	25 mg extract, 1% corosolic acid (about 0.25 mg)	Standardization matches published work, but the amount is below the early trials
BloodArmor	Not stated	Trials commonly used 16 to 48 mg of standardized extract
GlycoMute	Not stated	No standardization or amount, so no comparison is possible
CelluCare	Inside a 528 mg blend of 13 ingredients	About 40 mg each if split evenly, though blends are rarely even

The RegenVive review is worth reading closely because it is the rare case with a clear number. The company deserves credit for stating both the extract amount and the 1% standardization. But 25 mg of a 1% extract gives about 0.25 mg of corosolic acid, and the review says early banaba trials used roughly 32 to 48 mg of a similar 1% extract. The label is therefore lower than the research dose, not equal to it.

The BloodArmor review and the GlycoMute review describe the more common situation. Banaba is named, which sounds reassuring, but without a milligram figure or a corosolic acid percentage the reader cannot tell whether the capsule is near the trial range or nowhere close. In the CelluCare review, banaba is one of 13 ingredients that share a 528 mg proprietary blend, so no individual amount exists to check.

Why does banaba show up in formulas that are not for blood sugar?

Some offers list banaba or corosolic acid inside products sold for other goals. The Oradentum review covers a dental capsule whose ingredient list includes banaba leaf extract and corosolic acid, with amounts not stated. The review says this group of ingredients is more commonly associated with blood sugar formulas than dental ones, and that no dental study for the combination is cited on the site.

The same pattern appears in brain and weight formulas. The MemoVolt review lists corosolic acid among ingredients with no stated amount, and the Morning Fat Melter review records banaba leaf extract with no amount, against research that commonly used 8 to 48 mg of corosolic acid per day. The trials above looked at blood sugar in people with diabetes or metabolic syndrome. They do not show that a banaba line on another type of label will have any particular effect.

What should you check on a banaba label?

1. Is banaba (Lagerstroemia speciosa) listed on its own line with an amount in milligrams, or inside a proprietary blend?
2. Is it plain leaf, a leaf extract or an extract standardized to a percentage of corosolic acid?
3. If a percentage is stated, multiply it out. A 25 mg extract at 1% holds about 0.25 mg of corosolic acid.
4. Compare that number with the studies the page cites, in the same units, extract with extract.
5. Check that the cited studies are about the product's stated purpose and not about another ingredient.
6. Read the refund terms on the order form. Our ClickBank refund guide shows where to look, and our review method explains how we handle dose gaps.

If you take diabetes medicine or have a blood sugar condition, talk to your doctor or pharmacist before adding any supplement that is marketed for blood sugar.

Frequently asked questions

How much corosolic acid is in a banaba supplement?

Most labels do not say. When one does, you can calculate it: multiply the extract weight by the stated percentage. RegenVive lists 25 mg of extract at 1%, which is about 0.25 mg of corosolic acid.

Does banaba lower blood sugar?

Some small human trials report lower glucose with banaba extracts, including a 2003 trial at 32 and 48 mg a day and a 2022 trial at 500 mg twice a day. The studies are small and short. NCCIH says there is no reliable evidence that herbal supplements can control diabetes, so a banaba capsule should not replace medical care.

What does standardized to 1% corosolic acid mean?

It means the extract is made so that corosolic acid makes up about 1% of its weight. That lets you estimate the amount of the compound and compare the product with studies that used the same type of extract.

Is banaba the same as Lagerstroemia speciosa?

Yes. Banaba is the common name, and the research literature uses the Latin name Lagerstroemia speciosa. A label that gives the Latin name and the part of the plant used is easier to match to studies.