It sounds like it could be what's often referred to as TJ-68, which is a blend of white peony and licorice root that's been around for a long time... there's a few clinical studies indicating that it can reduce blood testosterone, has a history of usage in Japan and China, and would have a similarly off-putting sweet taste (plenty of people don't like licorice/anise after all). On the other hand, there are other things that have similar effects and the leaves/roots in the image don't look like them.