Stevia is a plant. It grows in the ground and requires plenty of water and sunshine to produce a profitable crop for farmers. Stevia is processed for use in a manner similar to how plant-based ingredients like sugar or vanilla extract are made. After this process, the molecules in stevia leaf extract are the same molecules that were found in the original leaf.
To date, there is not one definition around the world for the term “natural” or in many cases there is simply no definition, as is the case in the United States. Given this, stevia is most appropriately referred to as a natural origin sweetener because it arises from the leaves of the stevia plant.