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 melanocortin receptor agonist derived from Melanotan II. Unlike Melanotan II, PT-141 was developed specifically for sexual dysfunction and received FDA approval in 2019 as Vyleesi for hypoactive sexual desire disorder (HSDD) in premenopausal women.
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.
Activates melanocortin receptors (MC3R and MC4R) in the central nervous system, increasing sexual desire through a brain-based mechanism rather than vascular effects. This distinguishes it from PDE5 inhibitors like sildenafil which work peripherally.
- Maintaining fertility during TRT
- Pituitary function testing
- Hypothalamic amenorrhea treatment
- Post-cycle therapy (PCT)
- Preserving testicular size during hormone therapy
- Female sexual dysfunction (FDA-approved indication)
- Male sexual dysfunction (off-label)
- Libido enhancement
- Erectile dysfunction (off-label)
- Injection site reactions
- Headache and nausea
- Flushing
- Potential for desensitization with continuous (non-pulsatile) use
- Allergic reactions (rare)
- Nausea (most common side effect — ~40% in trials)
- Flushing
- Headache
- Transient blood pressure increase
- Hyperpigmentation with repeated use
- Injection site reactions
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.
FDA-approved as Vyleesi (bremelanotide injection) in June 2019 for hypoactive sexual desire disorder (HSDD) in premenopausal women. Off-label use for male sexual dysfunction is common through telehealth clinics. Available through compounding pharmacies with 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.