Sadly, if you take progesteronic (I made that word up) steroids and use nolvadex, you may be at an increased risk for progesteronic sides, as nolvadex may increase progesterone receptors (Gynecol Oncol. 1999 Mar;72(3):331-6). So besides competing with estrogen at the receptor, these drugs both increase serum test levels, and both drugs may also alter blood lipid profiles. With regards to Clomid and Nolvadex, I’ve found some research that indicates that 20mgs of tamoxifen is equal to 150mgs of clomid for purposes of testosterone elevation, FSH and LH, but tamoxifen did not decrease the LH response to LHRH (Fertil Steril. 1978 Mar;29(3):320-7). Interestingly, Nolvadex can even be used in small doses just as effectively as larger doses, when it comes to sperm indices and spermatogenesis. (“Effect of lower versus higher doses of tamoxifen on pituitary-gonadal function and sperm indices in oligozoospermic men”. Dony JM, Smals AG, Rolland R, Fauser BC, Thomas CM.) So in this case, we can actually use much lower doses than the egregiously recommended 40-60mgs/day. 5mgs a day seems to be as effective as 20, with regards to basal or LHRH stimulated gonadotropin and testosterone response or the E2/T ratio (Ibid).