This site says Cinnamon Bark and Chromium round out the formula's metabolic support.
The phrasing positions these two as supporting players behind Berberine and Gymnema, not as headline ingredients. That fits the site's own framing of a balanced, four-ingredient formula.
Because both are tied to glycemic and insulin-related roles, the site's insulin and metformin caution applies to the formula as a whole. Read the pairing and the caution together.