Peptide Reference

Ipamorelin: The Selective GH Secretagogue Without the Cortisol Spike

A focused reference on mechanism, research dosing, CJC-1295 pairing, and what the human trial data actually shows.

July 13, 2026 4 min read BioStackIQ Editorial
Ipamorelin GH Secretagogue Growth Hormone
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What Is Ipamorelin and How Does It Work

Ipamorelin is a pentapeptide classified as a selective growth hormone secretagogue - it mimics ghrelin at the pituitary gland's ghrelin receptor (GHS-R1a), triggering a clean, pulsatile release of growth hormone. What distinguishes it from older-generation secretagogues in the same class (GHRP-2, GHRP-6, hexarelin) is receptor selectivity: those earlier compounds also stimulate cortisol and prolactin release as a side effect of their broader receptor activity, while Ipamorelin's more selective binding profile largely avoids that spillover in research models.

Because it works through a different receptor pathway than GHRH analogs like CJC-1295 or Sermorelin, Ipamorelin is frequently studied in combination with them rather than alone - the two mechanisms are additive, producing a larger GH pulse than either compound triggers independently.

Research Dosing

Dosing below reflects ranges reported in published research and common research-protocol conventions, not personal medical guidance.

Dose Frequency Timing Route
200–300mcg 1–3× daily Fasted - pre-sleep, pre-training, or on waking SubQ injection

Context: The fasted-state requirement is not optional in the research protocols this dosing is drawn from - insulin elevation after eating blunts the GH pulse these compounds are designed to trigger. Pre-sleep dosing is considered the most important single injection, aligning with the dominant natural GH pulse during slow-wave sleep.

Regulatory Status

Ipamorelin is not an FDA-approved drug and is not currently listed on the FDA's 503A or 503B bulk drug substance lists for compounding pharmacies. Products sold as "Ipamorelin" - including the one carried in the BioStackIQ shop - are marketed and sold as research chemicals for laboratory and research use only, not for human consumption. Consult a qualified healthcare provider before considering any peptide protocol.

What Research Shows

The foundational human research on Ipamorelin's receptor selectivity dates to the late 1990s, when it was first characterized as a selective GH secretagogue distinct from earlier GHRP compounds - specifically for its reduced effect on cortisol and prolactin at doses that still produced robust GH release.

Research reference: Raun K et al. "Ipamorelin, the first selective growth hormone secretagogue." Eur J Endocrinol. 1998;139(5):552-561. PMID: 9849822. View on PubMed

For the combined CJC-1295 + Ipamorelin stacking protocol - dosing schedule, timing around sleep and training, and cycle structure - see the peptide stacks for muscle growth guide.

Frequently Asked Questions

Disclaimer: This content is for informational purposes only. Ipamorelin is a research compound not approved by the FDA for human use. Always consult a qualified healthcare provider before starting any peptide protocol. Nothing in this article constitutes medical advice.