Tribulus terrestris is a spiny-fruited vine, and its steroidal saponins — chiefly protodioscin — are the reason it shows up in nearly every product in this category.
The trial evidence is stronger for libido than for a measurable rise in testosterone, a distinction most marketing copy in this space glosses over.
In Primordial Vigor X, it's one of three named botanicals inside the 870 mg total serving, with the split between them not published on the label.
In Primordial Vigor X: Tribulus Terrestris is one of three named botanicals in the 870 mg serving — see the full breakdown on our how it works page.