Gastrointestinal upset can occur when high doses are used, and due to its ability to reduce blood sugar, it may increase the risk for hypoglycemia in high doses, though this isn't a common occurrence.
Tentatively, yes, but a doctor's guidance is highly recommended. Berberine has been the subject of much research and seems to be potent like many pharmaceuticals.
The standard dose of berberine is 900-2,000mg a day, divided into three to four doses. Berberine should be taken with a meal, or shortly after, to take advantage of the blood glucose and lipid spike associated with eating. Too much berberine at once can result in stomach upset, cramping, and diarrhea.
This information in our Herbal Reference Guide is intended only as a general reference for further exploration, and is not a replacement for professional health advice. Accordingly, this information should be used only under the supervision of a qualified health practitioner.