Cortisol

Cortisol is the body’s primary glucocorticoid, secreted by the adrenal cortex under HPA-axis control. It mobilizes glucose, suppresses inflammation, and acts as a permissive signal for many other hormones. Diurnal cortisol peaks in the early morning and troughs in the late evening.

Cortisol elevation is a known side effect of less-selective GHRPs — GHRP-6 and to a lesser extent GHRP-2 elevate cortisol and prolactin alongside GH release. Ipamorelin is the GHS-R agonist most often selected because it does not significantly raise cortisol or prolactin at typical research doses.

Chronic cortisol elevation is associated with poor recovery, suppressed immune function, and accelerated aging biomarkers, which is why cortisol-sparing peptide selection matters for long-running protocols.