Interesting.

"Berberine induces GLP-1 secretion through activation of bitter taste receptor pathways"

https://www.sciencedirect.com/science/article/pii/S000629521...

But buyer beware when it comes to getting berberine from over-the-counter supplements:

"Variability in Potency Among Commercial Preparations of Berberine"

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5807210/

Nine of the 15 tested products (60%) failed to meet the potency standards of 90% to 110% of labeled content claim, as commonly required of pharmaceutical preparations by the U.S. Pharmacopeial Convention. Evaluation of the relationship between product cost and the measured potency failed to demonstrate an association between quality and cost. Variability in product quality may significantly contribute to inconsistencies in the safety and effectiveness of berberine. In addition, the quality of the berberine product cannot be inferred from its cost.

Worse still,

"Preparation and Evaluation of Antidiabetic Agents of Berberine Organic Acid Salts for Enhancing the Bioavailability"

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6337101/

Berberine—an isoquinoline alkaloid isolated from the rhizome of Coptidis rhizome, Cortex phellodendri, and other plant species—possesses a variety of pharmacological effects, including anti-cancer, anti-hyperglycemic, anti-hyperlipidemic, antimicrobial, anti-inflammatory, and antioxidant activities. However, its absolute bioavailability is as low as 0.68%. Low bioavailability greatly restricts the clinical development of berberine.