No change is an answer. What matters is what you do before the guarantee ends.
Compare your weekly averages with your baseline. Consider whether sleep, season, stress or training changed. The page describes effects as gradual, so you may feel you have not given it a full chance.
The guarantee is 60 days.
Request a refund in writing before the deadline, or continue knowingly with the window closed. If tiredness or low drive persists regardless, see a doctor, since a supplement is not the right tool for an unexplained problem.