Berberine is extracted from several different plants, and has been used in traditional Chinese medicine. It may protect against a range of chronic disease of aging, primarily by protecting against elevated blood sugar levels and insulin resistance, which is a major driver of many chronic diseases including diabetes, heart disease, cancer and fatty liver disease. In type II diabetics, berberine is one of the few supplements found to have similar effectiveness when compared to pharmaceutical drugs such as metformin, though the effects of berberine are still less well supported by research than most pharmaceuticals.
This article gives a more detailed overview of berberine and the evidence supporting its effects on blood sugar. Berberine may also aid weight loss, slow tumour growth, and protect against certain pathogens.
Berberine has a high potential to interact with medication, causing severe reactions in some cases.