Enclomiphene is the trans-isomer of clomiphene citrate. Clomid is roughly 60% enclomiphene and 40% zuclomiphene; enclomiphene alone is the cleaner option.
Mechanism — Selective estrogen receptor antagonist at the hypothalamus and pituitary, driving LH and FSH without zuclomiphene's slower-clearing estrogen-agonist isomer. Result: cleaner T elevation and fewer mood/visual side effects.
Use case — Secondary hypogonadism in younger men, fertility preservation, post-TRT restart. Typical 12.5-25 mg/day. Better tolerated than Clomid for most.
Caveats — Brand-name access in the US is limited; compounding pharmacy is the practical route. Still produces a testosterone response — not a substitute for TRT in primary hypogonadism.