Growth Hormone Axis
Peptides that stimulate endogenous growth hormone release and IGF-1 production.
Clinical Overview
Growth Hormone Axis
Peptides that stimulate endogenous growth hormone release and IGF-1 production.
Growth-hormone-axis peptides stimulate endogenous pituitary GH secretion, in contrast to exogenous recombinant GH. Combining a GHRH analog with a GH secretagogue (commonly CJC-1295 + ipamorelin) is synergistic because the two classes act on distinct pituitary receptors.
Mechanism Classes
GHRH analogs
Sermorelin, tesamorelin, and CJC-1295 activate the growth-hormone-releasing hormone receptor on pituitary somatotrophs, stimulating endogenous GH secretion.
Growth hormone secretagogues (GHS)
Ipamorelin, GHRP-2/6, and hexarelin act on the ghrelin receptor (GHS-R1a) to trigger additional GH release, synergistic with GHRH analogs.
Combination therapy
CJC-1295 (no-DAC) with ipamorelin is the most common clinical combination, dosed together subcutaneously at bedtime to leverage natural GH pulsatility.
Regulatory Status
FDA-Approved
- Tesamorelin (HIV lipodystrophy)
- Sermorelin (historical pediatric GH deficiency)
Investigational / Off-Label
- CJC-1295 / Ipamorelin
- Hexarelin
Tesamorelin is FDA-approved but frequently used off-label for adult indications. Sermorelin's historical FDA approval was withdrawn; current compounded use is off-label.
Evidence Base
Tesamorelin has FDA-approval-grade RCT data for lipodystrophy. Sermorelin has decades of historical clinical use. GH secretagogues (ipamorelin, hexarelin) have supportive but not approval-grade human data for adult indications.
Primary-Literature References
39
Across 3 linked monographs
Prescribing Considerations
- 1Baseline IGF-1, comprehensive metabolic panel, and pituitary axis screening before initiating therapy.
- 2Target IGF-1 in mid-to-upper range of age-appropriate normal — avoid supra-physiologic levels.
- 3Active or recent malignancy is a contraindication (IGF-1 mitogenic potential).
- 4Active proliferative diabetic retinopathy is a contraindication.
- 5Caution in uncontrolled diabetes (GH antagonizes insulin) and severe sleep apnea.
- 6Dose at bedtime to coincide with natural GH pulsatility; recheck IGF-1 at 6–12 weeks after reaching target dose.
Peptides in this category(3)
Clinical monographs for each agent — dosing ranges, safety profile, evidence, and prescribing considerations.
1 additional monograph in this category is in clinical review and will be published soon.