← DatabaseSelective Estrogen Receptor Modulator
Enclomiphene
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The trans-isomer of clomiphene, a SERM studied to raise endogenous testosterone by blocking estrogen feedback at the hypothalamus and pituitary; not FDA-approved as a standalone drug.
How it works
Enclomiphene is one of the two molecular forms that make up clomiphene, a long-used fertility medication. Drugs like this are called selective estrogen receptor modulators, meaning they can either block or mimic estrogen depending on the tissue. Enclomiphene is the form that primarily blocks estrogen's signal.
The brain constantly monitors estrogen levels and dials hormone production up or down accordingly. By blocking estrogen receptors in the hypothalamus and pituitary, enclomiphene makes the brain 'think' estrogen is low, prompting it to release more of the signals (LH and FSH) that tell the testes to make testosterone. The appeal is that it raises a man's own testosterone while, unlike injected testosterone, tending to preserve sperm production.
Enclomiphene has been studied in clinical trials for men with low testosterone but is not currently an FDA-approved standalone product; clomiphene itself is approved only for female infertility, and male and isomer-specific uses are off-label or investigational. Compounded enclomiphene is sold in some markets without the same oversight as approved drugs. Because it alters hormonal axes, it should be used only with medical guidance.
Mechanism · Detailed Analysis
Molecular targetEnclomiphene is the (E)-trans stereoisomer of clomiphene citrate and acts as an estrogen receptor antagonist at hypothalamic and pituitary estrogen receptors. It contrasts with zuclomiphene, the (Z)-cis isomer, which has more estrogen-agonist character and a much longer half-life.
Signaling & downstream effectsBy antagonizing estrogen-mediated negative feedback on the hypothalamic-pituitary-gonadal axis, enclomiphene increases pulsatile GnRH and thereby pituitary secretion of LH and FSH. Elevated LH stimulates Leydig-cell testosterone production while FSH supports spermatogenesis, allowing endogenous testosterone to rise without exogenous androgen suppression of fertility.
PharmacokineticsIt is orally active. Enclomiphene is cleared substantially faster than the zuclomiphene isomer, which is one rationale for isolating it from the clomiphene mixture to reduce accumulation of the longer-lived estrogenic component. Hepatic metabolism predominates.
CaveatsRegulatory status is the central caveat: enclomiphene is investigational and not an approved finished drug in the US, and much circulating product is compounded. SERM-class effects raise theoretical concerns around mood, visual disturbances, and thromboembolic risk seen with clomiphene. Long-term safety data specific to male hormonal use are limited.
Published EvidenceLoading cited studies from PubMed…
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Educational aggregation of public literature. Not medical advice and not a recommendation to use any compound. Many compounds here are not approved for human use. Consult a licensed clinician.