I am coming off of my first two weeks of clen on Fri. In regard to the two weeks off, I am planning on taking the ECA Stack for the next two weeks before resuming clen again. Will taking ephederine impair the receptors ability to upgrade for the next clen stack, or are the receptors effected by the ephederine different from those effected by the clen. today was day one of week two of clen and I took 100 mcg and barely felt it !!