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Home/Compounds/Nafarelin
OtherFDA approvedRx required

Nafarelin

Also known as: Synarel
Brands: Synarel

Intranasal GnRH agonist decapeptide used for endometriosis and central precocious puberty.

A
Grade A
Multiple human RCTs
Human studies28
PubMed citations29
Routeintranasal
Regulatory (US)FDA approved · Rx
Last verified2 days ago

Mechanism of action

GnRH agonist administered intranasally twice daily. Continuous receptor occupancy downregulates pituitary GnRH receptors.

Evidence summary

28
Human studies
29
PubMed citations
11
Clinical trials
A
Evidence grade

Evidence summary in progress. See the citations section below for the underlying research papers.

Dosing protocols

Educational information only. Consult a licensed provider before using any peptide.
Administration routes
intranasal

Side effects & safety

From the FDA label
Source
arthralgiaastheniaheadachepalpitationspruritusrashurticariavomiting

Terms pulled directly from the referenced source. We don't fabricate frequencies — when a label doesn't publish a percentage, we don't either.

Interactions

No documented drug interactions on file.

Regulatory status

United States
FDA approved

FDA approved for endometriosis and central precocious puberty (Synarel)

Compounding
Not permitted

Not available via 503A/503B compounding pharmacies.

Regulatory data last verified 4/19/2026

Clinical trials

NCT06150703Luteal Phase Support With GnRH Agonist Alone After GnRH Agonist Triggering and Fresh Embryo Transfer Compared to the Reference Protocol (hCG Triggering and Progesterone Luteal Support): a Randomised Controlled TrialRecruiting · Phase 3 · In Vitro Fertilization · n=652NCT06870266Comparison of Pregnancy Rates in Modified Natural Frozen Embryo Transfer (FET) Cycle After Luteal Support with GnRH Agonist Versus Progesterone: Prospective Randomized StudyNot Yet Recruiting · Phase 1 · Ivf · n=150NCT06763926Intranasal Nafarelin Compared to Subcutaneous Triptorelin for Triggering Final Oocyte Maturation in Ovarian Stimulation: a Non-inferiority Randomised Controlled Clinical TrialNot Yet Recruiting · Phase 4 · Fertility Disorders · n=134NCT04850261Injection Free Natural Cycle In Vitro Fertilisation by Using a Nasal GnRH Agonist to Induce Ovulation. Is it More Comfortable for Patients and Equally Effective as Subcutaneous hCG Injection?Withdrawn · Phase 2 · Fertility DisordersNCT05801705Comparative Evaluation of Efficacy and Safety of Toremifene, Tamoxifen, and Aromatase Inhibitor Plus Ovarian Suppression in Hormone Receptor-Positive Early Breast Cancer Among Non-Low-Risk Premenopausal Women: A Real-World StudyUnknown · Hormone-receptor-positive Breast Cancer · n=700NCT05484193Comparison of Pregnancy Rates After Luteal Phase Support With GnRH Agonist Versus Progesterone - a Prospective Randomized StudyUnknown · N/A · Use of GnRH Agonist Alone for Luteal Phase Support in Fresh IVF Cycles · n=150NCT04797338Luteal Phase Support Using Gonadotropin Releasing Hormone Agonist (GnRHa) Versus Estrogen and Progesterone Supplementation in High Responders Following GnRHa Triggering - A Prospective Randomized Controlled TrialUnknown · Phase 4 · Pregnancy Early · n=100NCT02865681Protocol to Minimize Injections and Blood Draws for Women Undergoing Controlled Ovarian Hyperstimulation for in Vitro FertilizationCompleted · N/A · Infertility · n=4NCT00756028Short Versus Long IVF-treatment. A Prospective, Consecutive and Randomized Comparative StudyCompleted · Phase 4 · Infertility · n=1099NCT00843570A Randomised Controlled Trial of Natural Versus Hormone Replacement Therapy Cycles in Frozen Embryo Replacement IVF: a Pilot StudyCompleted · Phase 4 · Infertility · n=159NCT00034047Endometriosis : Traditional Medicine vs Hormone TherapyCompleted · Phase 1 · Endometriosis · n=50

Citations

PMID 37016694Vercellini P, Bandini V et al. · Mitigating the economic burden of GnRH agonist therapy for progestogen-resistant endometriosis: why not?Human reproduction open (2023)HumanPMID 18173008Marinov B, Milanova K · [Some possibilities for application of "Pfizer" medicines--Prostin 15m, Prostin E2, Prepidil gel, Dostinex, Synarel--in the obstetrician practice].Akusherstvo i ginekologiia (2008)HumanPMID 16038370Cheng MH, Yu BK et al. · A randomized, parallel, comparative study of the efficacy and safety of nafarelin versus danazol in the treatment of endometriosis in Taiwan.Journal of the Chinese Medical Association : JCMA (2005)HumanPMID 14644830Valle RF, Sciarra JJ · Endometriosis: treatment strategies.Annals of the New York Academy of Sciences (2004)HumanPMID 14757511Raiman J, Koljonen M et al. · Delivery and stability of LHRH and Nafarelin in human skin: the effect of constant/pulsed iontophoresis.European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences (2004)HumanPMID 11804427Franco JG, Baruffi RL et al. · Prospective randomized comparison of ovarian blockade with nafarelin versus leuprolide during ovarian stimulation with recombinant FSH in an ICSI program.Journal of assisted reproduction and genetics (2002)HumanPMID 11228063Bergqvist A · A comparative study of the acceptability and effect of goserelin and nafarelin on endometriosis.Gynecological endocrinology : the official journal of the International Society of Gynecological Endocrinology (2001)HumanPMID 11532477Takeuchi S, Minoura H et al. · A prospective randomized comparison of routine buserelin acetate and a decreasing dosage of nafarelin acetate with a low-dose gonadotropin-releasing hormone agonist protocol for in vitro fertilization and intracytoplasmic sperm injection.Fertility and sterility (2001)HumanPMID 11212082Wong JM, Forrest KA et al. · Efficacy of nafarelin in assisted reproductive technology: a meta-analysis.Human reproduction update (2001)HumanPMID 10774095Calvo Lugo GE, Sauceda González LF et al. · [Treatment of pelvic endometriosis with goserelin acetate or nafarelin acetate. Comparative study].Ginecologia y obstetricia de Mexico (2000)HumanPMID 10900582Minaguchi H, Wong JM et al. · Clinical use of nafarelin in the treatment of leiomyomas. A review of the literature.The Journal of reproductive medicine (2000)HumanPMID 9663373Zhao SZ, Arguelles LM et al. · Cost comparisons between nafarelin and leuprolide in the treatment of endometriosis.Clinical therapeutics (1998)HumanPMID 9720832Audebert A, Descamps P et al. · Pre or post-operative medical treatment with nafarelin in stage III-IV endometriosis: a French multicenter study.European journal of obstetrics, gynecology, and reproductive biology (1998)HumanPMID 9776601Simberg N, Tulppala M et al. · Comparison of buserelin and nafarelin in IVF cycles and in subsequent frozen-thawed embryo transfer cycles.Acta obstetricia et gynecologica Scandinavica (1998)HumanPMID 9252932Agarwal SK, Hamrang C et al. · Nafarelin vs. leuprolide acetate depot for endometriosis. Changes in bone mineral density and vasomotor symptoms. Nafarelin Study Group.The Journal of reproductive medicine (1997)HumanPMID 7996307Garner C · Uses of GnRH agonists.Journal of obstetric, gynecologic, and neonatal nursing : JOGNN (1995)HumanPMID 8150114Dantas ZN, Vicino M et al. · Comparison between nafarelin and leuprolide acetate for in vitro fertilization: preliminary clinical study.Fertility and sterility (1994)HumanPMID 7951404Adamson GD, Kwei L et al. · Pain of endometriosis: effects of nafarelin and danazol therapy.International journal of fertility and menopausal studies (1994)HumanPMID 8116353Jacobson J, Harris SR et al. · Low dose intranasal nafarelin for the treatment of endometriosis.Acta obstetricia et gynecologica Scandinavica (1994)HumanPMID 1483292Eldred JM, Haynes PJ et al. · A randomized double blind placebo controlled trial of the effects on bone metabolism of the combination of nafarelin acetate and norethisterone.Clinical endocrinology (1993)Human

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