A new study suggests that raspberry leaf tea may play a role in managing blood sugar levels. At this point, however, experts don’t recommend drinking raspberry leaf tea for the sole purpose of lowering blood sugar. Raspberry leaf tea may offer a natural way to help manage blood sugar levels, according to a new study. Raspberry leaf tea is made from the red raspberry plant (Rubus idaeus), the same one that produces the berries. So while raspberry leaf tea could theoretically decrease blood sugar levels, it’s too soon to know for sure.