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Dr. Grey AI

Peptide

Nafarelin (Synarel)

Nafarelin is a synthetic GnRH agonist decapeptide with D-Nal(2) substitution at position 6. FDA-approved for endometriosis and central precocious puberty. Administered via nasal spray. Double-blind trials show >80% reduction in endometriosis extent, symptoms reduced from 40% severe to 5-10%. 39% pregnancy rate post-treatment. Also approved for CPP in children ages 8/9 and under.

Research notice. This page is for education and research. Peptides may not be FDA-approved for human use and may only be legally available for research. Talk to a qualified clinician before considering any peptide.

Best evidence
Grade A
Conditions studied
2
Outcomes
11
Graded outcomes
5132

Evidence by condition

  • Strong
  • Moderate
  • Limited
  • Very limited

2 conditions, plus general outcomes

Endometriosis

Endometriosis: outcomes studied for Nafarelin (Synarel)
GradeOutcomeEffectSizeStudiesPeopleStudies list
Post-Treatment Fertility

39% (58/149) achieved pregnancy after treatment completion. Comparable to danazol pregnancy rates.

Improves (the measure goes up)Moderate effect24 studies

Studies that measured post-treatment fertility

and 14 more in the citations list

Endometriosis Reduction

Double-blind trial: >80% of patients had laparoscopic reduction in endometriosis. AFS scores significantly improved vs baseline.

Improves (the measure goes down)Large effect23 studies

Studies that measured endometriosis reduction

and 13 more in the citations list

Pain Reduction

Severe painful symptoms decreased from 40% to 5-10%. 3-month course provides effective symptom relief with continued benefit at 1 year.

Improves (the measure goes down)Large effect23 studies

Studies that measured pain reduction

and 13 more in the citations list

Post-Surgical Efficacy

6 months nafarelin after laparoscopic surgery significantly delays symptom return vs placebo.

Improves (the measure goes up)Moderate effect23 studies

Studies that measured post-surgical efficacy

and 13 more in the citations list

Early-Onset Puberty

Early-Onset Puberty: outcomes studied for Nafarelin (Synarel)
GradeOutcomeEffectSizeStudiesPeopleStudies list
Puberty Suppression

Suppresses LH and sex steroids to prepubertal levels. Arrests secondary sexual development and slows linear growth.

Changes; see studiesLarge effect16 studies

Studies that measured puberty suppression

and 6 more in the citations list

General

General: outcomes studied for Nafarelin (Synarel)
GradeOutcomeEffectSizeStudiesPeopleStudies list
Reproductive Outcomes

6 human trials and systematic reviews support this finding. Evidence includes systematic reviews/meta-analyses. Human clinical trial data available.

Improves (the measure goes up)Small effect7 studies

Studies that measured reproductive outcomes

Safety/Tolerability

4 human trials support this finding. Human clinical trial data available.

Improves (the measure goes up)Small effect5 studies

Studies that measured safety/tolerability

Hormone Levels

3 preclinical studies support this finding. Primarily preclinical evidence.

Improves (the measure goes up)Small effect5 studies

Studies that measured hormone levels

Bone Mineral Density

4 preclinical studies support this finding. Primarily preclinical evidence.

Improves (the measure goes up)Small effect5 studies

Studies that measured bone mineral density

Lipid Profile

2 preclinical studies support this finding. Primarily preclinical evidence.

Improves (the measure goes down)Small effect3 studies

Studies that measured lipid profile

Liver Protection

2 human trials support this finding. Human clinical trial data available.

Improves (the measure goes up)Small effect3 studies

Key findings

  • Post-Treatment FertilityEndometriosisImproves (the measure goes up)
  • Endometriosis ReductionEndometriosisImproves (the measure goes down)
  • Pain ReductionEndometriosisImproves (the measure goes down)

Studies cited

35 studies from PubMed

  1. Elagolix (Orilissa)--an oral GnRH antagonist for endometriosis pain.The Medical letter on drugs and therapeutics, 2018 · PMID 30383729
  2. Prolonged injectable formulation of Nafarelin using in situ gel combination delivery system.Pharmaceutical development and technology, 2018 · PMID 28430010
  3. 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 · PMID 16038370
  4. 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 · PMID 14757511
  5. The case of the elusive androgen.Endocrine practice : official journal of the American College of Endocrinology and the American Association of Clinical Endocrinologists, 2002 · PMID 15260009
  6. Efficacy of nafarelin in assisted reproductive technology: a meta-analysis.Human reproduction update, 2001 · PMID 11212082
  7. Treatment of endometriosis with a decreasing dosage of a gonadotropin-releasing hormone agonist (nafarelin): a pilot study with low-dose agonist therapy ("draw-back" therapy)Fertil Steril, 2000 · PMID 10731543
  8. Treatment with nafarelin for endometriosis in young women. Efficacy, safety and lipid metabolism. Niigata Nafarelin Study Group.The Journal of reproductive medicine, 2000 · PMID 10900577
  9. [Conservative treatment of interstitial ectopic pregnancy and endometriosis with laparoscopic methotrexate and potassium chloride and complementary management with nasal nafarelin. Report of a case and review of the literature].Ginecologia y obstetricia de Mexico, 2000 · PMID 10774100
  10. Clinical use of nafarelin in the treatment of leiomyomas. A review of the literature.The Journal of reproductive medicine, 2000 · PMID 10900582
  11. Use of nafarelin versus placebo after reductive laparoscopic surgery for endometriosisFertil Steril, 1997 · PMID 9389816
  12. Retreatment with nafarelin for recurrent endometriosis symptoms: efficacy, safety, and bone mineral density.Fertility and sterility, 1997 · PMID 9176437
  13. Nafarelin vs. leuprolide acetate depot for endometriosis. Changes in bone mineral density and vasomotor symptoms. Nafarelin Study Group.The Journal of reproductive medicine, 1997 · PMID 9252932
  14. Therapeutic efficacy and bone mineral density response during and following a three-month re-treatment of endometriosis with nafarelin (Synarel).American journal of obstetrics and gynecology, 1997 · PMID 9423744
  15. Intranasal nafarelin versus buserelin (short protocol) for controlled ovarian hyperstimulation before in vitro fertilization: a prospective clinical trial.Gynecological endocrinology : the official journal of the International Society of Gynecological Endocrinology, 1996 · PMID 8862491
  16. Prospective randomized double-blind trial of 3 versus 6 months of nafarelin therapy for endometriosis associated pelvic painFertil Steril, 1994 · PMID 7720940
  17. Nafarelin therapy in endometriosis: long-term effects on bone mineral density.American journal of obstetrics and gynecology, 1994 · PMID 7977523
  18. Gonadotropin-releasing hormone agonist as a probe for the pathogenesis and diagnosis of ovarian hyperandrogenism.Annals of the New York Academy of Sciences, 1993 · PMID 8323171
  19. Nafarelin for endometriosis: a large-scale, danazol-controlled trial of efficacy and safety, with 1-year follow-up. The Nafarelin European Endometriosis Trial Group (NEET).Fertility and sterility, 1992 · PMID 1531464
  20. Nafarelin versus leuprolide in ovulation induction for in vitro fertilization: a randomized clinical trial.Obstetrics and gynecology, 1992 · PMID 1533022
  21. Hyperandrogenism--what is normal?The New England journal of medicine, 1992 · PMID 1535116
  22. Medical treatment of endometriosis: a comparison of the suppressive effects of danazol and nafarelin on reproductive hormones.Fertility and sterility, 1991 · PMID 1833245
  23. Efficacy and safety of nafarelin in the treatment of endometriosisAm J Obstet Gynecol, 1990 · PMID 2137971
  24. Nafarelin acetate: a gonadotropin-releasing hormone agonist for the treatment of endometriosisAm J Obstet Gynecol, 1990 · PMID 2151003
  25. Treatment of children with central precocious puberty by a slow-release gonadotropin-releasing hormone agonistEur J Pediatr, 1990 · PMID 2138079
  26. Nafarelin in the treatment of infertility caused by endometriosis.American journal of obstetrics and gynecology, 1990 · PMID 2137973
  27. Nafarelin in the treatment of pelvic pain caused by endometriosis.American journal of obstetrics and gynecology, 1990 · PMID 2137972
  28. Effects of nafarelin versus danazol on lipids and calcium metabolism.American journal of obstetrics and gynecology, 1990 · PMID 2137977
  29. Nafarelin. A review of its pharmacodynamic and pharmacokinetic properties, and clinical potential in sex hormone-related conditions.Drugs, 1990 · PMID 2140979
  30. Role of nafarelin in the management of endometriosisJ Reprod Med, 1989 · PMID 2533616
  31. A new test of combined pituitary-testicular function using the gonadotropin-releasing hormone agonist nafarelin in the differentiation of gonadotropin deficiency from delayed pubertyJ Clin Endocrinol Metab, 1989 · PMID 2529266
  32. Clinical experience treating endometriosis with nafarelinJ Reprod Med, 1989 · PMID 2533617
  33. Administration of nasal nafarelin as compared with oral danazol for endometriosis. A multicenter double-blind comparative clinical trialN Engl J Med, 1988 · PMID 2963213
  34. Treatment of endometriosis with a potent agonist of gonadotropin-releasing hormone (nafarelin)Fertil Steril, 1986 · PMID 2932349
  35. Ovulation inhibition with nafarelin acetate nasal administration for six months.Contraception, 1985 · PMID 2936564