PEPTIDESTAT
ApprovedReproductive & hormoneIntranasalEvidence 4/5

Nafarelin

Also known as: Synarel

Nafarelin is a potent GnRH receptor agonist that initially stimulates pituitary LH and FSH release but with continued dosing downregulates the receptor, suppressing gonadotropins and sex steroid production.

Read guideBuy / compare source
Nafarelin
Drug class
GnRH agonist (gonadotropin-releasing hormone analog)
Primary targets
GnRH receptor (pituitary gonadotrophs), LH, FSH, estradiol, testosterone
Dose reference
Per the FDA label (reference only, not a recommendation): endometriosis 400 mcg/day (one 200 mcg spray per nostril twice daily), increasable to 800 mcg/day; central precocious puberty 1600 mcg/day, increasable to 1800 mcg/day.
Half-life
Approximately 3 hours in adults (about 2.5 hours in children) after intranasal administration
Developer / origin
Syntex (now part of Pfizer)
Reference year
1990
Evidence score
4/5 - Approved with controlled-trial evidence

Approved uses

  • Endometriosis (management including pain relief and lesion reduction, up to 6 months)
  • Central precocious puberty
Evidence 4/5

Approved with controlled-trial evidence

Nafarelin (Synarel) is FDA-approved with randomized controlled-trial evidence for endometriosis (comparable to danazol for symptom control) and effective LH suppression in central precocious puberty, though benefits are duration-limited and constrained by hypoestrogenic bone-density loss.

Investigational compound with human randomized or phase 2/3 evidence.

Evidence basis

  • FDA-approved label (DailyMed) with two indications and defined dosing
  • NEET large danazol-controlled randomized trial in endometriosis
  • Multiple double-blind nafarelin-versus-danazol endometriosis trials
  • Manufacturer clinical pharmacology documenting LH/FSH suppression and prepubertal LH response in CPP
  • Label-documented ~8.7% trabecular bone-density loss at 6 months limiting duration

How to read this entry

Dose references and half-life values are pulled from trial protocols, labels, reviews, or published summaries where available. They are context for research and comparison, not a personal dosing recommendation.

Status matters: approved drugs have regulated indications; investigational compounds are still being studied; research-only peptides do not have established human dosing, safety, or efficacy for consumer use.

Nafarelin guides

Read the matching guide or adjacent research pages for more context.

Nafarelin Peptide: Synarel, Intranasal GnRH Agonist Uses and SafetyNafarelin is an approved intranasal GnRH agonist peptide marketed as Synarel for endometriosis and central precocious puberty, with clear hormone-suppression evidence and hypoestrogenic safety limits.Atosiban Peptide: Tractocile, Oxytocin Antagonist Tocolytic for Preterm LaborAtosiban is an EU-approved oxytocin and vasopressin receptor antagonist peptide used intravenously as a short-term tocolytic to delay preterm labor.Buserelin Peptide: Suprefact, GnRH Agonist Uses and Safety LimitsBuserelin is an approved GnRH agonist peptide (Suprefact) used for prostate cancer, endometriosis and IVF down-regulation, with strong hormone-suppression evidence and important safety limits.Carbetocin Peptide: Long-Acting Oxytocin Analog for Postpartum HemorrhageCarbetocin is an approved long-acting oxytocin analog peptide used to prevent postpartum hemorrhage, with a heat-stable formulation and label-backed evidence.

Peptide calculators

Use calculators for concentration, unit conversion and repeated-dose accumulation math.

Peptide reconstitution calculatorCalculate concentration, draw volume and syringe units from vial strength and BAC water.Open toolPeptide accumulation calculatorModel repeated dosing schedules with half-life, interval, peak and trough estimates.Open toolPeptide unit converterConvert mg, mcg, optional IU and syringe units from one reconstituted vial setup.Open toolPeptide chemistry calculatorAnalyze sequence length, molecular weight, composition, charge, hydropathy and notation.Open tool

Compare with related peptides

Stay inside the same research category and compare mechanism, status and evidence quality.

Triptorelin

Trelstar, Decapeptyl

5/5
Reproductive & hormoneApproved

Triptorelin is a potent GnRH-receptor agonist that first transiently stimulates LH and FSH release, then, with continuous exposure, downregulates and desensitizes pituitary GnRH receptors to suppress gonadotropins and sex steroids.

DetailsGuide

Goserelin

Zoladex

5/5
Reproductive & hormoneApproved

Goserelin is a synthetic decapeptide GnRH agonist that first stimulates and then, with continuous depot exposure, downregulates pituitary GnRH receptors to suppress LH, FSH and downstream sex steroids toward castrate or postmenopausal levels.

DetailsGuide

Buserelin

Suprefact

4/5
Reproductive & hormoneApproved

Buserelin is a GnRH receptor superagonist that initially stimulates and then, with continuous non-pulsatile exposure, desensitizes pituitary gonadotrophs to suppress LH, FSH and downstream testosterone or estradiol production.

DetailsGuide

Histrelin

Supprelin LA, Vantas

4/5
Reproductive & hormoneApproved

Histrelin is a GnRH receptor agonist that initially stimulates and then, through continuous implant delivery, downregulates pituitary GnRH receptors to suppress LH, FSH and sex steroid production.

DetailsGuide

Research & educational purposes only

The information on PeptideStat is for educational and research purposes only and is not medical advice. Many peptides discussed are research compounds not approved for human use. Always consult a qualified healthcare professional before making any health decisions. Articles may contain affiliate links — we may earn a commission at no extra cost to you.