Nafarelin

FDA-approved GnRH receptor agonistEstablished

Nafarelin is an FDA-approved GnRH receptor agonist. Nafarelin is a GnRH agonist whose D-naphthylalanine substitution at position 6 increases receptor affinity and resistance to degradation, giving sufficient bioavailability for nasal administration. Continuous receptor stimulation downregulates pituitary GnRH receptors after an initial gonadotropin rise, producing reversible suppression of ovarian or testicular steroid production.

Calculate Dose

For research use only.

Key Facts

CAS: 76932-56-4
Molecular Weight (MW): 1322.5 g/mol
Half-life: —
FDA status: Approved
Evidence level: FDA Approved
Human dose established: Yes
Administration Route: Intranasal
Frequency: Two or three times daily by indication
Last updated: Nov 7, 2026
Reviewed: Nov 7, 2026

Research summary

Intranasally administered GnRH receptor agonist approved for endometriosis and for central precocious puberty. One of the few peptide drugs delivered routinely by nasal spray.

Research evidence

Regulatory review (FDA label)2 reviewed sources
Controlled human trialsNone in reviewed sources
Early or uncontrolled human studiesNone in reviewed sources
Lab & animal studiesNone in reviewed sources

How it works

Each step shows whether the sources Peptide Library has reviewed include that kind of research. Counts are reviewed sources, not every study ever published. Reviews and programme summaries that describe human use are shown as "reported", not as trials, and registered trials without published results are listed but not counted. A higher step means research has progressed further; it does not mean a compound works better or is safer. Compounds whose evidence has not been reviewed yet show "Not reviewed" instead of a guess.

Peptide Library's Nafarelin profile summarises 5 cited studies listed in the Science section, the compound's regulatory status, and research-protocol parameters reported for it. It is a research reference, not medical advice.

Nafarelin dosage evidence

Nafarelin has FDA-approved human dosages as SYNAREL nasal spray, which delivers 200 mcg per spray. For central precocious puberty in children the label dose is 1600 mcg a day (8 sprays), raised to 1800 mcg a day if suppression is not adequate. For endometriosis in women aged 18 and over it is 400 mcg a day (one spray morning and evening), raised to 800 mcg a day if menstruation continues after 2 months, for 6 months.

FDA Approved

Dosage evidence summary for Nafarelin
Human dosing established	Yes
Route	Intranasal
Frequency	Two or three times daily by indication
Duration studied	Until puberty is wanted (central precocious puberty); 6 months (endometriosis)
Titration	The label allows one step up for each indication if suppression is not adequate.
Evidence level	FDA Approved
Last reviewed	2026-11-07

Research-reported dosing

Doses as studied, one row per regimen. Different trials used different regimens; they are listed separately rather than averaged.

Research-reported dosing for Nafarelin, one row per studied regimen
Study / context	Population	Dose	Route	Frequency	Duration	Outcome studied	Source
FDA label — SYNAREL, central precocious pubertyFDA-approved label · FDA prescribing information	Children of both sexes with central precocious puberty	1600 mcg a day: 2 sprays (400 mcg) into each nostril in the morning and evening. 1800 mcg a day if suppression is not adequate: 3 sprays (600 mcg) into alternating nostrils three times a day	Intranasal	Twice daily (1600 mcg) or three times daily (1800 mcg)	Until resumption of puberty is desired	Suppression of pituitary-gonadal activity	SYNAREL (nafarelin acetate) nasal solution — FDA prescribing information (Pfizer), DailyMed
FDA label — SYNAREL, endometriosisFDA-approved label · FDA prescribing information	Women aged 18 and over with endometriosis	400 mcg a day: one 200 mcg spray into one nostril in the morning and the other nostril in the evening; 800 mcg a day if regular menstruation continues after 2 months	Intranasal	Twice daily	6 months, started between days 2 and 4 of the menstrual cycle	Pain relief and reduction of endometriotic lesions	SYNAREL (nafarelin acetate) nasal solution — FDA prescribing information (Pfizer), DailyMed

Where sources disagree

The two indications use very different amounts: 1600–1800 mcg a day in central precocious puberty against 400–800 mcg a day in endometriosis.
For endometriosis the label says retreatment cannot be recommended because safety data are not available, and that bone density should be assessed before any retreatment.
The label advises waiting at least 2 hours after a dose before using a nasal decongestant, and avoiding sneezing during or right after a dose. It also warns of severe skin reactions and pseudotumor cerebri.

Nafarelin dosage in published studies and labels →

Sequence & molecular data

Sequence and molecular data for Nafarelin
Molecular formula	C66H83N17O13
Molecular weight	1322.5 g/mol
CAS number	76932-56-4
PubChem CID	25077405
FDA UNII	1X0094V6JV
DrugBank	DB00666

Identifiers link to the public PubChem, FDA Substance Registration (UNII), ChEMBL and DrugBank records for the same entity.

Science

Mechanism of Action

Nafarelin is a GnRH agonist whose D-naphthylalanine substitution at position 6 increases receptor affinity and resistance to degradation, giving sufficient bioavailability for nasal administration. Continuous receptor stimulation downregulates pituitary GnRH receptors after an initial gonadotropin rise, producing reversible suppression of ovarian or testicular steroid production.

Studies

Research statistics

352 PubMed publications · 68.0% human clinical research · 10 registered trials

Counts of published research through 2026-11-01, not evidence that it works. Publications by year, study types and trials · How publications are counted

Regulatory & research status

Nafarelin is an FDA-approved product for specific labelled indications. Approval does not extend to the research contexts described on this page, and approved products are prescription medicines.

Regulatory and research status for Nafarelin
FDA status	Approved
Research status	Approved product (see FDA status)
Availability	Prescription-Only
WADA (sport)	Unknown / Not Listed
Library classification	FDA-Approved

How FDA approval, compounding and research-only status differ

Benefits

—

Nafarelin side effects

No side effects listed yet for this entry.

Storage & stability

This compound is not supplied as a powder to be mixed, so the freeze-dried powder and reconstitution handling described for research peptides does not apply. Storage conditions are product-specific: follow the label or packaging of the product itself.

Nafarelin: frequently asked questions

What is Nafarelin?

Intranasally administered GnRH receptor agonist approved for endometriosis and for central precocious puberty. One of the few peptide drugs delivered routinely by nasal spray.

How does Nafarelin work?

Is Nafarelin FDA approved?

Yes. Nafarelin is approved by the FDA, and approved products are prescription medicines. Approval is always for specific indications studied in clinical trials, so an approved status does not mean the compound is approved for every use it is discussed for. Research-chemical material sold under the same name is not the approved product.

What peptides are similar to Nafarelin?

Compounds most often compared with Nafarelin include Leuprolide, Goserelin, Triptorelin and Histrelin. They are grouped by shared mechanism or research area rather than by equivalence, and their regulatory status and evidence base differ.

References

Related research, comparisons & guides

Related peptides

Compiled by Peptide Library Editorial · Reviewed Aug 30, 2026 · Updated Nov 7, 2026 · Version 2

This Nafarelin profile is compiled from published literature (5 cited studies linked above), public regulatory records and chemical registries. It describes what research reports; it is not medical advice, and nothing here is a dosing recommendation for humans. Peptide Library does not sell peptides. Editorial policy · How profiles are compiled · Report an error

Track Nafarelin research, inventory and reconstitution in the free Peptide Library app. Get the app for iOS or Android →