It's hard to say exactly what endocrine changes occur in humans with clen intake. In other animals it clearly has an effect on may hormones (most worrying for males is testicular damage). It almost certainly will have impact on GH, T3, insulin, neurotransmitters etc.. and seems to also affect conversion of estrogen from testosterone at the hypothalamic level. No one really knows what the magnitude or significance of any of this is in humans. BTW, this is true for all beta 2-adrenoreceptor agonists to a certain extent.