My wife started a cycle of Clen from a sponsor here. We started her at 20mcg and felt nothing for two days, bumped her up to 40 and still nothing for 2 days. Today she tried 60 and still does not feel a thing. We were worried maybe it was bad so I took 20mcg and man is my heart racing so I know it's good. Is it possible she is immune to the Clen or how far should she go up before she gives up on it? She has always been a heavy caffeine person (drinks black coffee) could this play a role?