Enclomiphene is the trans-isomer (E-isomer) of clomiphene citrate, a triphenylethylene-class selective estrogen receptor modulator (SERM). Unlike the cis-isomer (zuclomiphene), which has partial ERα agonist activity, enclomiphene exhibits preferential ERα antagonist activity — particularly in hypothalamic and anterior pituitary tissue — that underpins its research utility for HPG axis studies. The endocrine brake that enclomiphene targets is estrogen-mediated negative feedback: circulating estradiol (E2) binds ERα on GnRH neurons in the hypothalamic arcuate and preoptic nuclei, as well as on gonadotroph cells in the anterior pituitary, suppressing GnRH pulse frequency and amplitude and reducing pituitary sensitivity to GnRH input. By competitively antagonizing ERα at these central sites, enclomiphene eliminates this transcriptional repression, disinhibiting hypothalamic GnRH pulse generators and increasing pituitary responsiveness to GnRH signals — leading to elevated LH and FSH secre
Enclomiphene: SERM & Estrogen Feedback Research Guide
Enclomiphene is the trans-isomer of clomiphene and a selective estrogen receptor modulator (SERM) with ERα antagonist activity at the hypothalamus and anterior pituitary. By blocking estrogen negative feedback, it disinhibits GnRH pulse generation and augments LH/FSH secretion — a key research tool for HPG axis regulatory pharmacology.