Berberine supplementation can reduce glucose levels to prediabetic levels in people with early-stage type 2 diabetes. This was shown in a Chinese trial published in the Journal of Clinical Endocrinology and Metabolism in 2008.

Study
Endocrinologists from Shanghai Jiao Tong University School of Medicine conducted a study with 116 adults aged 25-70, recently diagnosed with type 2 diabetes. The diabetes was still mild, but not prediabetic. The subjects had already progressed beyond that stage.

The subjects were not yet receiving medication, although they were eligible for it.

The researchers divided the subjects into a control group and an experimental group.

For three months, the control group took two placebo capsules daily, while the subjects in the experimental group took two capsules containing berberine daily. Each capsule contained 500 milligrams of berberine. In total, the subjects took one gram of berberine daily.

The researchers used an extract from the roots of Coptis chinensis. It was at least 97 percent pure. Not all berberine supplements contain extracts with such purity.

Results
Berberine supplementation shifted glucose levels to a level expected in people with prediabetes. Apparently, berberine increases insulin sensitivity. [Figure]

The effect of berberine on blood pressure, interleukin-6, and triglycerides was even stronger. These values ​​shifted into the normal and healthy range.

Click on the table and figure below for a larger version.

Conclusion
"Given the benefits of berberine in lowering blood glucose, lipids, [...] and blood pressures, we speculate that berberine may be used for patients with type 2 diabetes and metabolic syndrome", the researchers write.

"Long-term study with a larger sample size is needed to confirm these findings."