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 neuropeptide that acts as the master regulator of the reproductive hormone axis. Kisspeptin neurons in the hypothalamus control the release of GnRH (gonadotropin-releasing hormone), which in turn drives LH and FSH production. Increasingly studied for fertility treatment, hypogonadism, and as a diagnostic tool for reproductive disorders. Also being explored for its role in emotional and sexual brain processing.
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 the KISS1R (GPR54) receptor on GnRH neurons in the hypothalamus, triggering GnRH release. This stimulates the anterior pituitary to release LH and FSH, which drive testosterone production in males and ovulation in females. Kisspeptin is the upstream 'gatekeeper' of the entire HPG axis.
- Maintaining fertility during TRT
- Pituitary function testing
- Hypothalamic amenorrhea treatment
- Post-cycle therapy (PCT)
- Preserving testicular size during hormone therapy
- Fertility treatment (investigational)
- Hypogonadism evaluation
- IVF protocols (as GnRH trigger alternative)
- Reproductive endocrinology research
- Libido and sexual function research
- Injection site reactions
- Headache and nausea
- Flushing
- Potential for desensitization with continuous (non-pulsatile) use
- Allergic reactions (rare)
- Injection site discomfort
- Headache and flushing
- Potential for ovarian hyperstimulation in women
- Short half-life requires frequent dosing or infusion
- Limited long-term safety data
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.
Not FDA-approved. Active clinical trials at Imperial College London and other institutions for fertility applications. Being studied as a safer alternative to hCG triggers in IVF (lower risk of ovarian hyperstimulation syndrome). No US-approved formulation exists.
This comparison is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional before starting any peptide therapy.