How Ipamorelin Affects Cortisol

Ipamorelin's cortisol-neutral profile is its most documented pharmacological selectivity point. The Raun et al. (1998, PMID 9849822) paper is the pivotal reference:

1. Pituitary GHS-R1a selectivity: Ipamorelin was specifically designed to activate GHS-R1a receptors on pituitary somatotrophs without significantly activating the same receptor type in hypothalamic CRH neurons or pituitary corticotrophs. Older GHRPs (GHRP-6, GHRP-2, hexarelin) lack this selectivity; they stimulate GHS-R1a in multiple tissues, including the hypothalamus and pituitary corticotrophs, producing ACTH and cortisol release as a direct pharmacological effect.
2. Raun et al. (1998) selectivity data: In a dose-escalation study in pigs, ipamorelin at 200 times the effective GH-releasing dose produced no significant change in ACTH or cortisol. At the same dose, GHRP-6 and GHRP-2 produced marked ACTH and cortisol elevations. This established ipamorelin's cortisol selectivity as a fundamental pharmacological differentiator.
3. Arvat et al. (1997, PMID 9285939) context: Hexarelin (a structurally related but non-selective GHRP) at 1 mcg/kg IV raises cortisol by 50 to 80% within 30 minutes through GHS-R1a activation in corticotrophs. This study, alongside Raun 1998, defines the spectrum: ipamorelin at the selective end, hexarelin at the non-selective end.
4. Practical consequence for bodybuilders: Cortisol is the primary catabolic hormone, antagonising testosterone and GH at the tissue level. Using a GHRP that simultaneously elevates cortisol partly counteracts the anabolic effects it is supposed to support. Ipamorelin avoids this self-defeating dynamic.

Standard ipamorelin protocol (200-300 mcg SC, 1-2 times daily):

• Morning cortisol (serum): no significant change from baseline; normal range 6 to 23 mcg/dL (170 to 635 nmol/L)
• ACTH: no significant change
• Salivary cortisol patterns: no disruption expected

Dose escalation: Raun et al. (1998) confirmed no ACTH or cortisol elevation at 200x the effective GH dose in animals. While human dose-escalation data are not published, the structural selectivity is well-characterised.

Contrast with non-selective GHRPs:

• GHRP-6 (100 mcg): raises cortisol approximately 50% above baseline acutely
• Hexarelin (1 mcg/kg): raises cortisol 50 to 80% above baseline (Arvat 1997)
• GHRP-2 (100 mcg): intermediate cortisol elevation, less than GHRP-6 but present
• Ipamorelin (200-300 mcg): no significant cortisol change (Raun 1998)

Routine cortisol monitoring is not required for ipamorelin protocols. No mechanistic or published clinical basis for cortisol disruption exists.

When to check cortisol:

• Symptoms of HPA dysfunction: unexplained fatigue, hypotension, salt craving, pigmentation changes, or difficulty recovering from illness
• When transitioning from GHRP-6 or hexarelin, baseline cortisol and a follow-up 4 to 6 weeks post-switch confirm normalisation
• Annual morning cortisol as part of a comprehensive panel is reasonable for long-term GH peptide users as a general baseline marker, not specifically because of ipamorelin

No cortisol-specific management is required for ipamorelin use.

Switching from GHRP-6 or hexarelin to ipamorelin:

• Transition is straightforward: begin ipamorelin at the standard dose on the same injection schedule
• Expect cortisol normalisation within 2 to 4 weeks of stopping the cortisol-elevating GHRP
• Some users report subjective improvements in recovery, mood, and sleep quality within 2 to 3 weeks of the switch, which is mechanistically consistent with lower ambient cortisol

Stack optimisation:

• CJC-1295 no-DAC (the standard ipamorelin partner) is also cortisol-neutral, making the combination the preferred pulsatile GH protocol for cortisol-sensitive users
• No phosphatidylserine, ashwagandha, or other cortisol-modulating supplements are needed specifically for ipamorelin management