This site names Chromium as an essential trace mineral studied for its role in supporting insulin sensitivity.
Berberine, Gymnema and Cinnamon are botanicals; Chromium is a mineral. This site pairs it with its sources list, which links the NIH Office of Dietary Supplements chromium fact sheet.
No amount is published for Chromium, so confirm the figure on your own bottle's label and mention it to your doctor if you take any blood-sugar-affecting medication.