Educational Notice
This cluster overview is written for researchers, clinicians, and informed adults seeking to understand the scientific literature on growth hormone secretagogues and related compounds. It is not medical advice, a treatment recommendation, or an endorsement of any specific use. All compounds in this cluster are prohibited in competitive sport under WADA regulations. Consult a qualified healthcare professional before making any health or treatment decisions.
Research Cluster
Growth Hormone Secretagogues & Metabolic Peptides
Growth hormone secretagogues stimulate the pituitary to release endogenous GH rather than introducing exogenous growth hormone directly. The pituitary acts as a governor: it can only release what it has, and its negative feedback systems remain intact. This cluster also includes AOD-9604 (a lipolytic hGH fragment) and MOTS-c (a mitochondrial-derived metabolic peptide) — grouped here due to WADA S2 classification, not mechanistic relationship to GH secretion.
Compounds
11
FDA Approved
1
Clinical Programs
5
WADA Status
All S2
Evidence Tiers
Approved Drug
Clinical Trials (Phase I+)
Pilot / Limited Human Data
Preclinical Only
CJC-1295 (No DAC): What the Research Shows
Short-acting GHRH analog studied for pulsatile growth hormone stimulation and body composition. Preclinical evidence only.
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CJC-1295 with DAC: What the Research Shows
Long-acting GHRH analog with albumin-binding extension for sustained GH elevation. Preclinical evidence only.
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GHRP-2: What the Research Shows
Synthetic GHS-R1a agonist studied for growth hormone stimulation and appetite regulation. Human pharmacokinetic data available.
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GHRP-6: What the Research Shows
GHS-R1a agonist studied for growth hormone release and appetite stimulation. Human pharmacokinetic data available.
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Hexarelin: What the Research Shows
Potent GHS-R1a agonist studied for growth hormone secretion and cardiac function. Phase I/II human data available.
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Ipamorelin: What the Research Actually Shows
Selective GHS-R1a agonist studied for GH stimulation with minimal cortisol or prolactin effect. Preclinical evidence only.
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WADA
MK-677 (Ibutamoren): What the Research Shows
Oral GHS-R1a agonist (not a peptide) studied for GH elevation and muscle preservation. Human trial data available; WADA prohibited.
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Sermorelin: What the Research Shows
FDA-approved GHRH analog for growth hormone deficiency diagnosis and treatment. Established clinical evidence.
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Tesamorelin (Egrifta): What the Research Shows
FDA-approved GHRH analog (Egrifta) for HIV-associated lipodystrophy. Established clinical evidence.
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How These Compounds Relate
The cluster contains three mechanistically distinct groups — and two compounds that don’t fit either.
Group 1: GHRH Receptor Agonists
Tesamorelin, sermorelin, and CJC-1295 (no DAC) all bind the GHRH receptor and use the cAMP/PKA intracellular pathway to drive GH exocytosis. They differ in half-life — from sermorelin’s ~10–20 minutes to CJC-1295 with DAC‘s ~14 days — and in regulatory history. Short-acting forms produce pulsatile GH stimulation that most closely matches natural GH physiology. CJC-1295 with DAC produces sustained continuous GH elevation — a pharmacologically distinct intervention despite sharing the receptor target.
Group 2: GHS-R1a Agonists (GHRPs and Ghrelin Mimetics)
Ipamorelin, GHRP-2, GHRP-6, hexarelin, and MK-677 all act at GHS-R1a using the IP3/calcium intracellular pathway. Ipamorelin is the most selective (minimal cortisol, no appetite stimulation). GHRP-6 produces the strongest appetite stimulation. Hexarelin is the most potent but desensitizes the fastest. MK-677 is the only oral compound and the only one with Phase II/III data. Combining a GHS-R1a agonist with a GHRHR agonist (Group 1) activates complementary intracellular pathways, producing a synergistic GH response — the pharmacological basis for the ipamorelin + CJC-1295 (no DAC) combination.
Group 3: Metabolic Outliers
AOD-9604 and MOTS-c share the cluster due to WADA classification and community co-use, not mechanistic relationship to GH secretion. AOD-9604 is a lipolytic hGH fragment with no GH receptor binding and no anabolic effects. MOTS-c is a mitochondria-derived peptide activating AMPK. Neither belongs in a GH axis protocol.
The Combination Principle
Combining compounds from Group 1 and Group 2 (GHRHR + GHS-R1a) is pharmacologically coherent — independent pathways converging on GH exocytosis. Combining two compounds from Group 2 (e.g., ipamorelin + MK-677) creates receptor redundancy, not synergy. The exception: hexarelin’s CD36 mechanism is separate from GHS-R1a, making its cardioprotective effects orthogonal to GH axis combinations.
WADA Prohibition — All Compounds in This Cluster
Every compound in the Growth Hormone Secretagogues cluster is prohibited under WADA S2: Peptide Hormones, Growth Factors, and Related Substances — both in-competition and out-of-competition. This includes tesamorelin despite its FDA-approved status for a medical indication. Athletes subject to anti-doping testing must treat all compounds in this cluster as hard prohibitions. Those with a documented medical need for an approved compound may apply for a Therapeutic Use Exemption through their national anti-doping organization.
Disclaimer
This cluster overview is produced for educational and research purposes only. Peptidings does not provide medical advice, diagnosis, or treatment recommendations. Evidence tiers reflect the highest quality of human clinical evidence currently available in the published literature and are applied consistently across the site. All WADA status information is current as of March 2026; verify current prohibited list at wada-ama.org.