Banaba extract is used as a natural health supplement and is made from the leaves of the banaba tree. Some research suggests that banaba extract may support blood sugar balance and weight loss. The primary active ingredient is corosolic acid, and there are also numerous possible synergists including lager-stroemin, flosin B and reginin A.
Banaba is a medicinal plant that grows in India, Southeast Asia and the Philippines. Traditional uses include brewing tea from the leaves as a treatment for diabetes and hyperglycemia (elevated blood sugar). The hypoglycemic (blood sugar lowering) effect of banaba leaf extract is similar to that of insulin which induces glucose transport from the blood into body cells.
The blood sugar regulating properties of banaba have been demonstrated in cell culture, animal and human studies. In isolated cells, the active ingredient in banaba extract, corosolic acid, is known to stimulate glucose uptake. In diabetic mice, rats and rabbits, banaba feeding reduces elevated blood sugar and insulin levels to normal. In humans with type II diabetes, banaba extract, at a dose of 16-48mg per day for 4-8 weeks, has been shown to be effective in reducing blood sugar levels (5%-30% reduction) and maintaining tighter control of blood sugar fluctuations. An interesting (side-effect) of tighter control of blood sugar and insulin levels is a significant tendency of banaba to promote weight loss (an average of 2-4 lbs. per month) without significant dietary alterations. It is likely that modulation of glucose and insulin levels reduces total caloric intake somewhat and encourages moderate weight loss.