Selectivity by design
Classical GHRPs (GHRP-2, GHRP-6, hexarelin) all produce off-target endocrine effects that make single-axis studies difficult. Ipamorelin was engineered specifically to remove those confounds, and radioimmunoassay data across multiple labs confirm that cortisol and prolactin responses remain at baseline even at doses that drive robust GH release.
Why researchers still use it
For any experiment where the pulsatile GH response is the variable of interest, ipamorelin gives a cleaner signal than any of its predecessors. Its short half-life (~2 hours) also makes it suitable for pulse-chase protocols that require rapid clearance.
Practical notes
Lyophilized ipamorelin is stable at −20 °C. Reconstituted material tolerates 2–8 °C storage well. Solubility in bacteriostatic water is excellent.