INS and Insulin resistance: Parameters taken into consideration from the authors were fasting glucose, fasting insulin, the HOMA index and the AUCINS; in all studies, berberine showed an improvement of the parameters with a reduction of insulin resistance in a statistically significant way only in berberine groups vs. placebo (p < 0.01 or p < 0.05), so berberine reduced insulin resistance but is not superior to metformin [19, 21, 22, 25].