Banaba leaves come from the tree of the same name. They contain over 40 bio active compounds and offer multiple health benefits, including the ability to lower blood sugar levels. The anti diabetic effect of banaba leaves is one reason why they’re popular. Researchers attribute this effect to several compounds, namely corosolic acid, ellagitannins, and gallotannins. Corosolic acid lowers blood sugar levels by increasing insulin sensitivity, enhancing glucose uptake, and inhibiting alpha-glucosidase, an enzyme that helps digest carbs. That’s why it’s claimed to have an insulin-like effect.