Berberine is an alkaloid found in the barks, leaves, twigs, rhizomes, roots, and/or stems of various plants, such as the barberry, Oregon grape, and tree turmeric. Traditionally, berberine has been used as an antimicrobial, antiprotozoal, and antidiarrheal agent in Ayurvedic medicine and traditional Chinese medicine. Most research in humans has examined berberine’s effects on markers of glycemic control, blood lipids, markers of liver function, and anthropometric parameters in people with metabolic disorders.
Evidence from clinical trials conducted in people with type 2 diabetes suggests that berberine is able to reduce blood sugar to a similar extent as some anti-diabetic drugs. In people with metabolic disorders, limited research suggests that berberine may improve blood lipids and liver enzymes, and reduce body weight and fat mass. However, most of the available trials examining the effects of berberine on the aforementioned outcomes are of poor methodological quality.
Although berberine appears to be generally safe in normal doses, more long-term research on its safety is needed. In some people, supplementation with berberine has been reported to cause gastrointestinal side effects, including diarrhea, constipation, flatulence, and stomach pain. Due to its ability to reduce blood sugar, berberine may increase the risk for hypoglycemia in high doses. Berberine has a high potential of interacting with a number of drugs, with some of these interactions increasing the chances of serious complications.
The main mechanism through which berberine exerts its effects appears to be the stimulation of the enzyme adenosine monophosphate-activated protein kinase (AMPK), a master regulator of cellular energy homeostasis that is involved in a wide range of biological processes, including the regulation of glucose, lipid, and protein metabolism.