Selective oestrogen receptor modulator

Enclomiphene is the trans isomer of clomiphene, the fertility pill, taken on its own without the longer-lasting cis isomer zuclomiphene. By blocking oestrogen feedback on the brain, it raises LH and FSH and so the body's own testosterone. In phase 2 and 3 trials in men with secondary hypogonadism, 12.5–25 mg a day raised testosterone about as much as testosterone gel while keeping sperm counts normal, which the gel did not. Regulators in the US and Europe declined to approve it, and development stopped in 2021.