The Tribulus Terrestris that we have for sale does contain protodioscin, as all tribulus terrestris products will in varying degrees. The density of this phytochemical will vary depending upon the location from which it is sourced.
According to one particular study (below), the most abundant source of protodioscin is found from Bulgarian leaves. This is where the Now Foods Tribulus that we sell sources their raw materials from, and manufactures the supplement in the USA.
[Ganzera, M., et al., Determination of steroidal saponins in Tribulus terrestris by reverse-phase high-performance liquid chromatography and evaporative light scattering detection. Journal of Pharmaceutical Sciences 90(11), 1752-1758 (2001)],