Compare Peptides
Select any two compounds for a side-by-side comparison of mechanism, uses, risks, and FDA regulatory status.
Popular comparisons
A synthetic form of the naturally occurring gonadotropin-releasing hormone (GnRH). Used clinically to evaluate pituitary function and increasingly prescribed in peptide therapy to maintain endogenous testosterone production during TRT or peptide cycles. Acts on the pituitary to stimulate LH and FSH release.
A synthetic analog of growth hormone-releasing hormone (GHRH) that stimulates the pituitary gland to produce more growth hormone. Available with or without a Drug Affinity Complex (DAC) that extends its half-life.
Binds to GnRH receptors on gonadotroph cells in the anterior pituitary, triggering pulsatile release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). This maintains the HPG axis feedback loop and preserves testicular function, including spermatogenesis.
Binds to GHRH receptors on the pituitary gland, stimulating pulsatile release of growth hormone. The DAC version binds to albumin in the blood, extending the half-life from minutes to approximately 6-8 days.
- Maintaining fertility during TRT
- Pituitary function testing
- Hypothalamic amenorrhea treatment
- Post-cycle therapy (PCT)
- Preserving testicular size during hormone therapy
- Growth hormone optimization
- Improved sleep quality
- Fat loss
- Muscle recovery
- Anti-aging protocols
- Injection site reactions
- Headache and nausea
- Flushing
- Potential for desensitization with continuous (non-pulsatile) use
- Allergic reactions (rare)
- Water retention
- Tingling or numbness
- Potential cortisol elevation
- Limited long-term safety data
- May affect blood sugar levels
FDA-approved as Factrel for diagnostic evaluation of pituitary gonadotroph function. Lutrelef (pulsatile gonadorelin) approved in 2024 for hypothalamic amenorrhea. Widely compounded for off-label use in fertility preservation during TRT.
Reclassified to Category 1 in February 2026 as part of the HHS announcement restoring compounding access. Not affected by the April 15, 2026 Category 2 removal action. Available through licensed 503A compounding pharmacies with a physician prescription.
This comparison is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional before starting any peptide therapy.