Follitropin alfa

A recombinant human follicle-stimulating hormone produced in a Chinese hamster ovary cell line. It is approved in the United States for ovulation induction and multiple follicular development in women, and for induction of spermatogenesis in infertile men with hypogonadotropic hypogonadism whose infertility is not due to primary testicular failure and who have first been treated with hCG until serum testosterone normalises. It is not a testosterone therapy and has no labeled role in testosterone replacement, TRT-induced hypogonadism, or post-cycle recovery.

Follitropin alfa is structurally indistinguishable from pituitary FSH and binds the FSH receptor. In women it stimulates granulosa cells and drives follicular growth; in men it acts on Sertoli cells to support spermatogenesis, which additionally requires intratesticular testosterone generated by concurrent hCG.

Yes. Follitropin alfa is approved by the U.S. FDA and has official prescribing information. Evidence level: approved labeling. Official prescribing information exists, based on clinical trials in people.

Reported half-life: Terminal half-life per the US label differs by sex. In healthy male volunteers: approximately 41 hours after a single subcutaneous dose and approximately 32 hours with multiple dosing. In healthy female volunteers: approximately 24 hours after a single dose. Elimination after subcutaneous administration is absorption-rate limited.

Subcutaneous injection.

Reported in the sources: Contraindicated in women and men with prior hypersensitivity to recombinant FSH products or one of their excipients (reactions have included anaphylaxis), high FSH levels indicating primary gonadal failure, uncontrolled non-gonadal endocrinopathies (for example thyroid, adrenal or pituitary disorders), sex hormone-dependent tumours of the reproductive tract and accessory organs, and tumours of the pituitary gland or hypothalamus. Additionally contraindicated in women with abnormal uterine bleeding of undetermined origin, or ovarian cyst or enlargement of undetermined origin. Pregnancy is not a listed contraindication on this label; it is a pre-treatment exclusion and an embryofetal toxicity warning; Hypersensitivity reactions and anaphylaxis, requiring discontinuation and supportive treatment; Ovarian hyperstimulation syndrome, which may require hospitalisation, together with abnormal ovarian enlargement, ovarian torsion and reported ovarian neoplasms; Pulmonary and vascular complications, including thromboembolic events; Multi-fetal gestation and birth, ectopic pregnancy, spontaneous abortion and embryofetal toxicity; Requires clinician laboratory monitoring throughout treatment; in men this includes serum testosterone during hCG pretreatment and semen analysis to assess response; In men, the most common reported adverse reactions are acne, injection site pain, fatigue, gynecomastia and seborrhea. Most of the Warnings and Precautions section concerns female use; the male adverse reaction list is short and derived from smaller populations, so male-specific long-term safety is less well characterised than the female data; Product presentation matters: the GONAL-f RFF Redi-ject label is indicated for women only and contains no male dosing.