OK from what I've been reading Ephedra continues to keep working to increase metabolism. The only effects that are lost over time are the side effects increased heart beat and blood pressure jitteryness ect.. Now I havn't found any medical proof stating that it should be cycled, only from what I've heard here on the boards. Now I'm sure that the caffine gets immune to but I'm not so sure about ephedra stopping to work to get the 3% increase in metabolism. What about yohimbe any reason to cycle that?