Supplement Scholar
GnRH Analog

Nafarelin

Research compound. This is not a dietary supplement. Unless it is identified as an approved prescription drug, it is not approved by the FDA for human use. This page summarizes published research for education only; we do not sell it or link to sellers.

Nafarelin. Intranasal GnRH agonist used in endometriosis and central precocious puberty.

How it works. Continuous GnRH receptor stimulation downregulates pituitary gonadotropin release, suppressing gonadal steroid output.

What the research supports. 2 graded claims. Strongest: Non-injectable HPG-axis suppression (preclinical).

Hormonal impact. Effects on LH and FSH, Estradiol, Testosterone.

Side effects and interactions. 1 medication interaction listed. Serious: Bone loss with prolonged use.

Stacking. Pairs well with Add-back hormone therapy in long courses. Avoid combining with Pregnancy.

Common forms. Available as Intranasal spray.

Community. Experiences from people who have tried Nafarelin. Anecdotes are not medical advice.

Nafarelin. Intranasal GnRH agonist used in endometriosis and central precocious puberty.

Molecular structureC66H83N17O13 · 1322.5 g/mol

What it is

Nafarelin is a long-acting GnRH agonist delivered by nasal spray, used to suppress the HPG axis after an initial flare.

Also called

Synarel

How it works

Continuous GnRH receptor stimulation downregulates pituitary gonadotropin release, suppressing gonadal steroid output.

Pathways

  • GnRH receptor
  • LH/FSH suppression
  • Gonadal steroid suppression

Effects

  • ↓Estrogen-driven endometriotic activity decreases
  • ↓Premature pubertal progression decreases

What the research supports

Non-injectable HPG-axis suppressionpreclinical
Reversible on discontinuationpreclinical

Strong: consistent results across large trials or meta-analyses. Moderate: several trials, mostly positive. Limited: small or mixed studies. Preclinical: animal or cell research only.

Hormonal impact

↓LH and FSHdecreases
↓Estradioldecreases
↓Testosteronedecreases

Side effects & interactions

Common side effects

  • Hot flashes
  • Vaginal dryness
  • Mood changes

Serious

  • Bone loss with prolonged use
  • Initial flare worsening of underlying disease

Medication interactions

Hormonal contraceptivesmoderate

Confounds intended hormonal suppression.

Check any supplement–medication combination with your pharmacist before starting.

Combines with

Pairs well

  • Add-back hormone therapy in long coursesLimits bone and vasomotor effects.

Avoid combining

  • PregnancyContraindicated.

Common forms

  • Intranasal spray

Discussion

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