PCT & Ancillaries Peptide Dosage Protocols
Post-cycle therapy and ancillary research compounds restore endogenous hormone production after androgenic protocols. Covers aromatase inhibitors (anastrozole, letrozole, exemestane), SERMs (tamoxifen, raloxifene, enclomiphene), and prolactin modulators (cabergoline, pramipexole).
8 protocols indexed
Triptorelin
Triptorelin is a synthetic decapeptide gonadotropin-releasing hormone (GnRH/LHRH) agonist sold as Trelstar, Decapeptyl, Diphereline, Gonapeptyl and Triptodur. It is the native GnRH sequence with the glycine at position 6 replaced by D-tryptophan (pGlu-His-Trp-Ser-Tyr-D-Trp-Leu-Arg-Pro-Gly-NH2), a single substitution that resists peptidase degradation and makes it roughly 100-fold more potent than endogenous GnRH [4][9]. Continuous (non-pulsatile) receptor stimulation first triggers a brief LH/FSH and sex-steroid surge, then desensitizes pituitary GnRH receptors, producing reversible medical castration with testosterone falling below 50 ng/dL by week 3-4 [2][7]. The correct Triptorelin dosage depends entirely on the goal. The flagship clinical use is the long-acting pamoate depot for advanced prostate cancer: 3.75 mg every 4 weeks, 11.25 mg every 12 weeks, or 22.5 mg every 24 weeks as a single intramuscular injection [2][7]. The immediate-release acetate is dosed at 100 mcg subcutaneously, used daily for IVF/ART pituitary down-regulation and as a single shot in the validated triptorelin stimulation test for hypogonadotropic hypogonadism [5]. A single 100 mcg subcutaneous shot is also promoted in bodybuilding circles for post-cycle therapy, but that use has never been studied in a controlled trial and is research/educational only. Triptorelin (Trelstar) is FDA-approved (2000) for prostate cancer, with Triptodur approved in 2017 for central precocious puberty, and Decapeptyl is widely EMA-approved across Europe. Research-grade vials are sold for laboratory use only.
Open Protocolarrow_forwardGnRH Agonist (Nonapeptide)Buserelin
Buserelin is a synthetic nonapeptide gonadotropin-releasing hormone (GnRH/LHRH) agonist, the D-Ser(tBu)6, des-Gly10 ethylamide analog of native GnRH, marketed as Suprefact, Suprecur and Profact. Like other GnRH analogs it has a biphasic action: a continuous dose first stimulates the pituitary (a brief testosterone/estradiol "flare"), then within 1-3 weeks desensitizes and down-regulates GnRH receptors, shutting off LH and FSH and lowering sex steroids by roughly 95% to castrate or menopausal levels [2][3]. The headline Buserelin dosage for advanced hormone-dependent prostate cancer is 500 mcg subcutaneously every 8 hours for 7 days, then 200 mcg once daily, or a switch to the intranasal spray at 400 mcg three times daily; endometriosis and uterine fibroids are treated with the nasal spray (400 mcg three times daily) for up to 6 months [1][5]. In assisted reproduction, buserelin is used for pituitary down-regulation in the IVF "long protocol," and a single 500 mcg subcutaneous bolus can replace hCG as an ovulation trigger [4][6]. Subcutaneous bioavailability is about 70% with a plasma half-life of roughly 50-80 minutes (1-2 hours intranasally); a biodegradable depot implant can suppress testosterone for around 224 days [3]. Buserelin is approved in the UK, EU, Canada and Australia but is NOT FDA-approved in the United States. The figures on this page are a subcutaneous reconstitution reference for education only and are not medical advice.
Open Protocolarrow_forwardGnRH AgonistLeuprolide
Leuprolide (leuprolide acetate; brand names Lupron and Eligard) is a synthetic nonapeptide analog of gonadotropin-releasing hormone (GnRH/LH-RH) and a member of the GnRH agonist class. By substituting D-leucine at position 6 and capping the C-terminus with an ethylamide, the molecule resists peptidase breakdown and binds the pituitary GnRH receptor roughly 80-100 times more potently than native GnRH. Although it is an agonist, continuous (non-pulsatile) receptor occupancy down-regulates the receptor and ultimately suppresses luteinizing hormone (LH), follicle-stimulating hormone (FSH), and the gonadal sex steroids testosterone and estradiol. The headline Leuprolide dosage in the original immediate-release form is 1 mg (1000 mcg) injected subcutaneously once daily, the regimen validated in the pivotal 1984 prostate cancer trial. To avoid daily injections, leuprolide is also supplied as long-acting depots dosed 7.5 mg monthly, 22.5 mg every 3 months, 30 mg every 4 months, and 45 mg every 6 months, plus gynecologic depots (3.75 mg monthly, 11.25 mg every 3 months) and pediatric depots for central precocious puberty. Leuprolide is FDA-approved (prescription) for advanced prostate cancer, endometriosis, uterine fibroids, and central precocious puberty, and is widely used off-label in assisted reproduction. This page models the daily subcutaneous protocol as an educational reconstitution reference; the depot products are clinician-administered and are reconstituted with their own supplied diluent rather than bacteriostatic water.
Open Protocolarrow_forwardGnRH Antagonist PeptideCetrorelix
Cetrorelix (brand name Cetrotide) is a synthetic decapeptide gonadotropin-releasing hormone (GnRH/LH-RH) antagonist used in assisted reproduction to prevent premature luteinizing hormone (LH) surges during controlled ovarian stimulation. Built on the native GnRH decapeptide backbone with several D-amino-acid substitutions (Ac-D-Nal-D-Phe(4Cl)-D-Pal-Ser-Tyr-D-Cit-Leu-Arg-Pro-D-Ala-NH2), it competitively blocks pituitary GnRH receptors and produces an immediate, dose-dependent, reversible fall in LH and FSH without the initial "flare-up" seen with GnRH agonists. The headline Cetrorelix dosage is 0.25 mg (250 mcg) injected subcutaneously once daily during the late follicular phase (the multiple-dose protocol), or a single 3 mg subcutaneous injection that controls the LH surge for roughly four days (the single-dose protocol) [1][4][6]. Cetrorelix is genuinely a subcutaneous peptide, so the reconstitution figures on this page mirror its real clinical route; in practice each strength ships as a single-use vial reconstituted with the supplied sterile water and injected into the lower abdomen [1]. Pharmacokinetically it is rapidly absorbed (Tmax ~1-2 h), has roughly 85% subcutaneous bioavailability, and shows a terminal half-life that lengthens with dose, from about 5 hours after a single 0.25 mg dose to roughly 63 hours after a 3 mg dose [1][2]. Cetrorelix is FDA-approved (2000) and EMA-approved for inhibition of premature LH surges in women undergoing controlled ovarian stimulation; this page is an educational dosing reference, not medical advice.
Open Protocolarrow_forwardLongevity & Metabolic SupportGonadorelin
Gonadorelin is synthetic gonadotropin-releasing hormone (GnRH), an endogenous decapeptide (pGlu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2) produced by hypothalamic neurons. Pulsatile GnRH release stimulates pituitary secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which in turn drive gonadal steroidogenesis and gametogenesis. Gonadorelin has been FDA approved historically (Factrel injection, Lutrepulse pump) for evaluation of pituitary gonadotrope function and for induction of ovulation in hypothalamic amenorrhea, although original branded products have been withdrawn from the U.S. market. Diagnostic doses are 0.1 mg subcutaneously or intravenously; pulsatile therapy uses 5–20 mcg every 90–120 minutes via portable infusion pump. Off-label, gonadorelin is increasingly used at 50–200 mcg subcutaneously two to three times weekly as an adjunct in testosterone replacement therapy to preserve testicular volume and fertility, in place of hCG.
Open Protocolarrow_forwardResearch PeptideHCG
Human chorionic gonadotropin (hCG) is a glycoprotein hormone composed of an alpha subunit shared with LH, FSH, and TSH and a unique beta subunit. Produced by the syncytiotrophoblast during pregnancy, hCG acts as a luteinizing hormone receptor agonist on Leydig cells in the testes and theca/granulosa cells in the ovary, driving steroidogenesis and supporting the corpus luteum during early gestation. Recombinant and urinary-derived hCG are FDA approved for ovulation induction, prepubertal cryptorchidism, and hypogonadotropic hypogonadism. In post-cycle therapy and as an adjunct to testosterone replacement, hCG is used at 500–1500 IU subcutaneously two to three times weekly to restore endogenous testicular function suppressed by anabolic-androgenic steroids or exogenous testosterone. Typical PCT protocols use 1000–2000 IU every other day for two to three weeks before transitioning to selective estrogen receptor modulators. hCG is not approved for weight loss; the FDA has explicitly warned against this off-label use.
Open Protocolarrow_forwardResearch PeptideHMG
Human menopausal gonadotropin (hMG, menotropins) is a purified mixture of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) activity extracted from the urine of postmenopausal women, typically in a 1:1 FSH:LH bioactivity ratio. Menopur (highly purified hMG) and similar branded products are FDA approved for controlled ovarian stimulation in women undergoing assisted reproductive technology (ART) and for induction of ovulation in anovulatory women. Standard fertility protocols initiate hMG at 75–225 IU subcutaneously daily, titrating up to 450 IU/day based on follicular response. In men with hypogonadotropic hypogonadism, hMG (75–150 IU subcutaneously three times weekly) is combined with hCG to drive spermatogenesis. In off-label male PCT applications, hMG is used at 75–150 IU two to three times weekly to support FSH-driven Sertoli cell recovery alongside hCG-driven Leydig cell stimulation, although controlled clinical evidence in this context is limited.
Open Protocolarrow_forwardResearch PeptideKisspeptin
Kisspeptin is a family of RF-amide neuropeptides encoded by the KISS1 gene (the founder peptide kisspeptin-54 and its cleavage products kisspeptin-14, -13, and -10) that act through the G-protein-coupled receptor KISS1R (GPR54) to control the hypothalamic gonadotropin-releasing hormone (GnRH) pulse generator [1][2]. Arcuate nucleus kisspeptin neurons co-expressing neurokinin B and dynorphin (KNDy neurons) generate the rhythmic discharges that drive GnRH and downstream LH secretion, while rostral periventricular kisspeptin neurons mediate the estradiol-positive feedback surge required for ovulation. Loss-of-function mutations in KISS1 or KISS1R cause hypogonadotropic hypogonadism in humans, anchoring the genetic role of the pathway [3]. Skorupskaite, Dhillo, Anderson, and colleagues have demonstrated in controlled clinical studies that kisspeptin administration potently stimulates LH release in healthy men and women and can trigger oocyte maturation in IVF cycles with dramatically reduced risk of ovarian hyperstimulation syndrome [4][5][6]. Kisspeptin-10 and kisspeptin-54 are not FDA approved; they remain investigational agents under active clinical development. Research dosing typically uses 0.1 to 1.0 nmol/kg subcutaneous or intravenous boluses, or 4 nmol/kg/h infusions over several hours.
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