^^^ there are other factors that are going to influence libido (positively or negatively), moreso than Prime..Prime is a unique blend of trib, with different properties than what ppl think of when they think 'tribulus terrestris'..even within regular trib, you have to distinguish between levels of saponins & protodioscin - all trib is not created equal.
however, I don't think I've ever seen any study anywhere that shows any form of trib will decrease libido.
same thing w/ Terminalia Chebula.
my guess is you had other factors influencing that result in you, Daniel.