Fertility Research Peptides

5 research peptides demonstrate fertility properties. This collection covers their mechanisms, evidence base, and research applications.

Approved Medication with Strong Human Data | Reproductive / Hormonal

As a GnRH antagonist, it provides immediate suppression of gonadotropins without the initial flare characteristic of GnRH agonists, allowing for shorter and more flexible IVF stimulation protocols.

Mechanism: Ganirelix competitively blocks GnRH receptors on pituitary gonadotrophs, immediately suppressing LH and FSH secretion without an initial stimulatory phase. This direct antagonism prevents premature LH surges that could cause premature ovulation during controlled ovarian hyperstimulation, which would compromise oocyte retrieval in IVF. The molecule contains multiple D-amino acids and unnatural amino acid modifications that provide high receptor affinity and enzymatic resistance. LH levels are suppressed within 4-8 hours of administration. The elimination half-life is approximately 12-16 hours, requiring daily dosing. Ganirelix is metabolized by hepatic peptidases and partially excreted in urine and feces.

Approved Medication with Strong Human Data | Reproductive / Hormonal

Like ganirelix, it provides immediate GnRH receptor blockade without the hormonal flare of GnRH agonists. Cetrorelix (Cetrotide) is available in both 0.25 mg (daily) and 3 mg (single-dose) formulations, offering flexibility in IVF protocol design. It was one of the first GnRH antagonists developed for reproductive medicine.

Mechanism: Cetrorelix competitively binds to GnRH receptors on anterior pituitary gonadotrophs, immediately blocking the action of endogenous GnRH and suppressing LH and FSH release. This prevents premature LH surges during ovarian stimulation, which would trigger ovulation before oocyte retrieval. The molecule contains D-amino acid substitutions and other modifications that provide high receptor binding affinity. The 0.25 mg dose suppresses LH within 2-4 hours with a duration of approximately 24 hours (requiring daily dosing). The 3 mg dose provides suppression for approximately 96 hours (4 days), after which daily 0.25 mg doses may continue if needed. The elimination half-life is approximately 5-10 hours for the 0.25 mg dose and approximately 20-30 hours for the 3 mg dose. Cetrorelix is metabolized by peptidases and excreted via bile and urine.

Approved Medication with Strong Human Data | Reproductive / Hormonal

Buserelin is a synthetic GnRH agonist nonapeptide analog (MW ~1299.5 g/mol) with a D-Ser(tBu) substitution at position 6 and an NHEt modification at position 10. It is approved in the European Union, Canada, Australia, and other countries for the treatment of advanced prostate cancer, endometriosis, and as part of IVF protocols, but it is not approved by the FDA in the United States.

Mechanism: Buserelin is a GnRH agonist approximately 20-40 times more potent than native GnRH. Like other GnRH agonists, it operates through the "flare then suppression" mechanism. Initial administration causes transient stimulation of pituitary gonadotrophs, resulting in an LH and FSH surge with temporary increases in testosterone (men) or estradiol (women) during the first 1-2 weeks. Continuous administration causes GnRH receptor downregulation and desensitization, leading to suppression of LH and FSH secretion. Testosterone falls to castrate levels within 2-4 weeks in men; estradiol falls to postmenopausal levels in women. The half-life of the free peptide is approximately 1-2 hours. It is metabolized by tissue peptidases.

FDA-approved with extensive clinical evidence | Reproductive / Hormone Support

Human Menopausal Gonadotropin (HMG) is a purified hormonal preparation containing both follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in approximately equal ratios. Originally extracted from the urine of postmenopausal women, modern preparations (e.g., Menopur) use highly purified or recombinant forms. HMG is a cornerstone of fertility medicine, used for controlled ovarian stimulation in IVF and treatment of hypogonadotropic hypogonadism. In the performance enhancement community, it is used for post-cycle therapy and testicular recovery.

Mechanism: FSH component binds to FSH receptors on Sertoli cells (males) and granulosa cells (females), promoting spermatogenesis and follicular development respectively. LH component binds to LH receptors on Leydig cells (males) to stimulate testosterone production and on theca cells (females) to produce androgens for estrogen synthesis. The dual FSH+LH stimulation provides more complete gonadal stimulation than either component alone, which is why HMG is considered superior to hCG monotherapy for certain indications.

Approved drug (Eastern Europe) with clinical studies | Bioregulator / Urological

Prostatilen is a bioregulatory peptide complex extracted from bovine prostate tissue, developed by the Khavinson group in Russia and used clinically in Eastern European countries since the 1990s. It exerts organotropic (organ-specific) effects on prostate tissue through anti-inflammatory, immunomodulatory, and microcirculation-enhancing mechanisms. Clinical studies spanning over 1,400 patients report a 96.7% response rate for chronic prostatitis symptoms. Prostatilen AC is an enhanced formulation containing zinc arginyl-glycinate for additional reproductive support.

Mechanism: Prostatilen contains short peptide fragments that exhibit organotropic activity toward prostate tissue. These peptides normalize the prooxidant-antioxidant balance, restore microcirculation in prostatic vasculature, and modulate local immune responses. The anti-inflammatory effect involves reduction of leukocyte infiltration and edema. The peptide complex also corrects hemostatic parameters and may stimulate spermatogenesis through improved prostatic secretory function. The AC variant adds zinc arginyl-glycinate, which provides additional antioxidant protection and supports testosterone metabolism.