My doctor is skeptical of berberine

QUESTION
My doctor is skeptical of berberine, never heard of it, thinks Metformin is safe. Do you have any references I could print to address berberine is good and Metformin is hard on kidneys?

ANSWER

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2410097/ This study shows that berberine is as effective at lowering A1C and fasting glucose levels as Metformin, along with also improving total cholesterol and triglycerides, which Metformin did not.