Berberine is an alkaloid found in the barks, leaves, twigs, rhizomes, roots, and/or stems of various plants, such as 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.^[1][2][3] 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 (T2D) suggests that berberine’s glucose-lowering effect may be on par with some anti-diabetic drugs or standards of care.^[4][5] In people with metabolic disorders, limited research suggests that berberine may improve blood lipids and liver enzymes, and reduce body weight and fat mass.^[6] However, most of the available trials examining the effects of berberine on the aforementioned outcomes are of poor methodological quality.^[7] The best-quality clinical evidence on berberine’s effects to date are related to improvements in hormonal health in polycystic ovarian syndrome (PCOS) and to immune system response. Even these studies, however, warrant interpretation with a degree of caution due to the imprecision and inconsistency of their results.^[7] In those with PCOS, the evidence suggests that berberine may improve hormonal outcomes.^[4] In those with a variety of metabolic conditions (T2D, dyslipidemia, cardiovascular disease), berberine may be able to lower C-reactive protein (CRP), a biomarker of inflammation.^[8] Finally, in those with a history of colorectal cancer, it was found that berberine could potentially reduce the recurrence rates of colorectal polyps.^[9]

Although berberine appears to be generally safe, more long-term safety research is needed. Supplementation with berberine (especially in doses above 300 mg/day) has been reported to cause gastrointestinal side effects in some people, including diarrhea, constipation, flatulence, and stomach pain.^[10] Due to its ability to reduce blood sugar, berberine may increase the risk for hypoglycemia in high doses. Additionally, berberine inhibits several enzymes involved in drug metabolism, so there’s a risk of serious drug interactions when taken alongside other medications or supplements.^[11]

Berberine seems to produce most of its benefits through acting on high-level controllers of energy homeostasis, including the enzymes adenosine monophosphate-activated protein kinase (AMPK), protein kinase c (PKC), and sirtuin 1 (SIRT 1), all of which regulate biological processes related to metabolism, immunity, and inflammation.^[12]