Yup, lots of things will work for 2-3 weeks to boost your libido then stop:
1 Starting Testosteone shots,
2 Supressing estrogen with
Arimidex (even without the testosteone shots)
3. Stopping an antridepressent like lexapro (probably causes a dopamine rebound)
Perhaps that is how long it takes the receptors to down regulate after the change in
hormone levels.
The other possibility is that this is how things are supposed to work. Maybe libido
responds to the change in hormone level rather than the absolute level. Note that
the female system has a "cycle length" of about 3 weeks. There maybe some connection.
Or maybe it is all a plecebo effect.