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Growth Hormone — Selective GHRP✓ FDA Approved

Ipamorelin

Also known as: IPA · Ipam

MW

711.85 Da

Amino Acids

5 AA

Half-Life

2 hours

Route

SubQ

CAS

170851-70-4

Formula

C38H49N9O5

Amino Acid Sequence

Aib-His-D-2-Nal-D-Phe-Lys-NH2

Mechanism of Action

Ipamorelin is a synthetic pentapeptide and the most selective growth hormone releasing peptide (GHRP) discovered. It is a ghrelin mimetic that activates the same receptor as ghrelin but with greatly improved selectivity for GH release only.

PRIMARY MECHANISM — GHS-R1a ACTIVATION: Binds GHS-R1a on anterior pituitary somatotrophs. GHS-R1a is Gq-coupled → phospholipase C → IP3/DAG → intracellular calcium release → calcium-dependent exocytosis of GH granules. This is a completely different second-messenger pathway than GHRH/CJC-1295 (cAMP/PKA) — the two pathways converge on GH secretion from different angles.

SOMATOSTATIN SUPPRESSION ("REMOVING THE BRAKE"): Ipamorelin simultaneously suppresses somatostatin release from the hypothalamus. While CJC-1295 activates the GH "accelerator," ipamorelin removes the "brake." This dual action explains the 2–4x synergy.

CRITICAL SELECTIVITY: Raun et al. 1998 (PMID 9349622) showed ipamorelin produces robust GH release with NO significant elevation of cortisol, prolactin, or ACTH — unlike GHRP-2 and GHRP-6. The selectivity comes from ipamorelin's unique binding conformation at GHS-R1a.

HUNGER: Unlike GHRP-6, ipamorelin produces only mild transient hunger that resolves within 30 minutes.

DOWNSTREAM: GH pulse → liver IGF-1 (1.5–3x elevation) → satellite cell activation, lipolysis, collagen synthesis, slow-wave sleep enhancement.

Dosing Protocol

Low Dose

███ – ███ mcg/day

Standard Dose

███ mcg/day

High Dose

███ – ███ mcg/day

Dosing protocols are for paid members

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Frequency

Once nightly pre-sleep.

Half-Life

2 hours

Reconstitution Guide

Full reconstitution protocol with BAC water volumes, concentration math, and units-to-draw per dose is available on the Clinical plan.

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Clinical Warnings

WADA PROHIBITED.

IGF-1 monitoring every 8 weeks.

Cancer absolute contraindication.

Fasting required — carbs within 2hr blunt response.

Carpal tunnel = dose too high.

Receptor desensitization after 3–4 months — cycle off.

Do not confuse with GHRP-2/GHRP-6 (different side effect profiles).

Contraindications

Absolute

Active cancer

Pregnancy

Active pituitary tumor

Relative Cautions

Diabetes

History of cancer

Obesity

Side Effect Profile

Mild

  • Mild hunger increase
  • Water retention
  • Injection site reaction

Moderate

  • Headache
  • Lightheadedness
  • Tingling extremities

Severe (Rare)

  • Potential tumor growth acceleration

Synergistic Peptides

CJC-1295GHRP-2TesamorelinSermorelin

Common Stacks

CJC-1295

GHRP-2

Research Status

MODERATE. Raun 1998 (PMID 9349622): cleanest GHRP, no cortisol/prolactin vs GHRP-2/6. Gobburu 1999 (PMID 10545477): human PK/PD, 2-hour half-life, dose-response characterized. Post-bowel surgery tolerability confirmed.

Frequently Asked Questions

How does Ipamorelin work?

Ipamorelin is a synthetic pentapeptide and the most selective growth hormone releasing peptide (GHRP) discovered. It is a ghrelin mimetic that activates the same receptor as ghrelin but with greatly improved selectivity for GH release only. PRIMARY MECHANISM — GHS-R1a ACTIVATION: Binds GHS-R1a on anterior pituitary somatotrophs. GHS-R1a is Gq-coupled → phospholipase C → IP3/DAG → intracellular calcium release → calcium-dependent exocytosis of GH granules. This is a completely different second-m

What is the standard dose of Ipamorelin?

Ipamorelin dosing protocols are available with a ClinPep Clinical subscription. Dosing varies by indication and patient factors — consult a licensed healthcare provider. General frequency: Once nightly pre-sleep.

What is the half-life of Ipamorelin?

The half-life of Ipamorelin is 2 hours. This determines optimal dosing frequency and timing.

Who should not use Ipamorelin?

Ipamorelin is absolutely contraindicated in: Active cancer; Pregnancy; Active pituitary tumor. Use with caution in: Diabetes; History of cancer; Obesity.

What are the side effects of Ipamorelin?

Common mild side effects include: Mild hunger increase, Water retention, Injection site reaction. Moderate effects: Headache, Lightheadedness, Tingling extremities.

What peptides stack well with Ipamorelin?

Ipamorelin is commonly stacked with: CJC-1295, GHRP-2, Tesamorelin, Sermorelin.

How do you reconstitute Ipamorelin?

Ipamorelin is reconstituted with bacteriostatic water. Exact volumes, concentrations, and units-to-draw calculations are available in the ClinPep Clinical plan. Always follow your compounding pharmacy's instructions.

How long should you cycle Ipamorelin?

Ipamorelin cycle protocols vary by indication. Detailed cycle length, on/off schedules, and monitoring guidelines are available with ClinPep Clinical access. Consult your healthcare provider for personalized cycling guidance.

References & Citations

2 PubMed studies · 2 clinical trials

The growth hormone secretagogue receptor 1a agonists, anamorelin and ipamorelin, inhibit cisplatin-induced weight loss in ferrets: Anamorelin also exhibits anti-emetic effects via a central mechanism.

Lu Zengbing, Ngan Man P, Liu Julia Y H, Yang Lingqing et al.. Physiology & behavior. 2024

PubMed: 39043357DOI ↗C — Research Article

This study investigated whether ghrelin mimetics, namely anamorelin and ipamorelin, can alleviate weight loss and inhibition of feeding observed during acute and delayed phases of cisplatin-induced em

Peptidomimetic growth hormone secretagogue derivatives for positron emission tomography imaging of the ghrelin receptor.

Fowkes Milan M, Lalonde Tyler, Yu Lihai, Dhanvantari Savita et al.. European journal of medicinal chemistry. 2018

PubMed: 30282322DOI ↗C — Research Article

The ghrelin receptor is a seven-transmembrane (7-TM) receptor known to have an increased level of expression in human carcinoma and heart failure. Recent work has focused on the synthesis of positron

Registered Clinical Trials

Safety and Efficacy of Ipamorelin for Management of Post-Operative Ileus

NCT00672074COMPLETEDPHASE2

Safety and Efficacy of Ipamorelin Compared to Placebo for the Recovery of Gastrointestinal Function

NCT01280344COMPLETEDPHASE2

Symptom Indications

Low GH levelsPoor sleepPoor recoveryMuscle lossAgingLow energy

Full Clinical Access

Complete Ipamorelin Protocol

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This information is for educational and research reference purposes only. ClinPep does not provide medical advice, diagnosis, or treatment recommendations. All protocols should be reviewed by a licensed healthcare provider.