Gymnema Sylvestre
Commonly called Gymnema.
It blocks receptors in your intestines and thus sugar absorption, Lowering your post-meal blood sugar levels.
https://www.sciencedirect.com/science/article/abs/pii/0378874190901075
The effect of Gymnema Sylvestre supplementation on glycemic control in type 2 diabetes patients
https://www.ingentaconnect.com/content/ben/cpd/2017/00000023/00000011/art00011
https://www.sciencedirect.com/science/article/abs/pii/S0031698981800744