ENCLO RESEARCH CHEMICAL (30 CAP)

Enclomifene (INNTooltip International Nonproprietary Name), or enclomiphene (USANTooltip United States Adopted Name), a nonsteroidal selective estrogen receptor modulator of the triphenylethylene group, acts by antagonizing the estrogen receptor (ER) in the pituitary gland, which reduces negative feedback by estrogen on the hypothalamic-pituitary-gonadal axis, thereby increasing gonadotropin secretion and hence gonadal production of testosterone.^[4] It is one of the two stereoisomers of clomifene, which itself is a mixture of 38% zuclomifene and 62% enclomifene.^[4] Enclomifene is the (E)-stereoisomer of clomifene, while zuclomifene is the (Z)-stereoisomer.^[5][6] Whereas zuclomifene is more estrogenic, enclomifene is more antiestrogenic.^[4] In accordance, unlike enclomifene, zuclomifene is antigonadotropic due to activation of the ER and reduces testosterone levels in men.^[4] As such, isomerically pure enclomifene is more favorable than clomifene as a progonadotropin for the treatment of male hypogonadism.^[4]

Enclomiphene (former tentative brand names Androxal and EnCyzix), was under development for the treatment of male hypogonadism and type 2 diabetes.^[5][6][7][4] By December 2016, it was in preregistration and was under review by the Food and Drug Administration in the United States and the European Medicines Agency in the European Union.^[7] In January 2018, the Committee for Medicinal Products for Human Use of the European Medicines Agency recommended refusal of marketing authorization for enclomifene for the treatment of secondary hypogonadism.^[1] In April 2021, development of enclomifene was discontinued for all indications.^[7]