HCG (Human Chorionic Gonadotropin)

Ten publications are cited, from 2009 to 2025, and nine concern people. They include a short-course randomised study of hCG, clomiphene citrate and both together in hypogonadal men, a comparison of hCG with testosterone in late-onset hypogonadism, a 2024 systematic review and meta-analysis of gonadotropins for inducing puberty in boys, and a 2009 pooled analysis of phase 3 data on recombinant FSH with hCG. Five further clinical reports cover puberty induction in adolescent boys, adult fertility after gonadotropin-induced puberty, testosterone-to-oestradiol ratios, symptomatic men with total testosterone above 300 ng/dL, and sperm recovery after testosterone use. The tenth is a study in male rats.

The randomised study reported that hCG, clomiphene and their combination restored testosterone to a similar degree, and the late-onset hypogonadism study compared semen parameters between men given hCG and men given testosterone. The meta-analysis described the evidence that gonadotropins induce puberty in boys with hypogonadotropic hypogonadism as convincing, and the pooled phase 3 analysis reported that recombinant FSH with hCG restored fertility in most men with the condition. Adolescent boys given corifollitropin alfa and then corifollitropin alfa with hCG showed testicular growth, pubertal progression, rising testosterone and a growth spurt. A 2021 study proposed the testosterone-to-oestradiol ratio as a predictor of response, noting that symptoms linked to raised oestradiol could persist despite normal testosterone. The 2025 study reported recovery of sperm production with hCG and FSH in men who had used testosterone, unimpeded by continued testosterone use, and the study in men with total testosterone above 300 ng/dL recorded no adverse events. In male rats, hCG reversed hypogonadism induced by craniectomy with or without brain injury, which the authors attributed to reduced hypothalamic or pituitary function rather than testicular failure.

The one study described as randomised was short-course. The meta-analysis itself noted wide variation in agents, doses, durations and outcomes, and called for randomised studies and formal guidelines. Several studies gave hCG with FSH, corifollitropin alfa or clomiphene, so its separate contribution cannot be isolated in those results, and the 2024 fertility report presents its findings as early proof of concept. The entries shown here do not state sample sizes.