Ipamorelin (S2)

Ipamorelin (NNC 26-0161)

The most selective GHRP available, stimulating GH release with minimal cortisol or prolactin elevation.

Prohibited in competition. This compound is on the WADA Prohibited List (class [S0 / S2.3 / S2]), banned at all times, both in and out of competition. Athletes subject to WADA or USADA testing should not use it.

100% 50% · t½ ≈ 2h 25% 0h 2h 4h 6h 8h Serum level Time →
Molecular Weight 711.85 Da
Half-Life ~2 hours
Typical Dose 200–300 mcg
Cycle Length 8–16 weeks,
with 4-week breaks

Description

Ipamorelin (NNC 26-0161) is a synthetic pentapeptide and one of the most selective growth hormone secretagogues ever developed. Discovered by Novo Nordisk in the 1990s, it was designed to maximize GH-releasing potency while minimizing off-target hormonal effects. Unlike earlier GHRPs such as GHRP-2 and GHRP-6, Ipamorelin does not significantly elevate cortisol, prolactin, or ACTH at standard doses, making it the preferred GHRP for long-term use. It is almost universally combined with CJC-1295 No DAC (a GHRH analog) to produce synergistic GH pulses through complementary receptor systems. Ipamorelin has completed Phase II clinical trials for post-operative ileus and has an excellent safety profile in human studies.

Key Characteristics

Molecular Formula

C38H49N9O5

Molecular Weight

711.85 Da

Half-Life

~2 hours

Administration Routes

Subcutaneous injection, Intramuscular injection

Typical Dose

200–300 mcg

Frequency

2–3x daily (or once before bed)

Investigated Benefits

* Benefits based on preclinical/animal research unless otherwise noted.

Mechanism of Action

“The most selective GHRP available, stimulating GH release with minimal cortisol or prolactin elevation.”

Ipamorelin acts as a ghrelin mimetic, binding to the growth hormone secretagogue receptor 1a (GHS-R1a) — a Gq/11 protein-coupled receptor expressed on somatotroph cells in the anterior pituitary. GHS-R1a activation triggers phospholipase C (PLC) signaling, generating IP3 and DAG, which increases intracellular calcium and stimulates GH exocytosis. Ipamorelin’s selectivity for GH release over cortisol and prolactin is due to its specific binding conformation at GHS-R1a, which activates GH-releasing pathways without triggering adrenocorticotropic or lactotropic signaling cascades. When combined with CJC-1295 No DAC (which acts on GHRHR via the cAMP/PKA pathway), the two peptides act on distinct intracellular signaling cascades that converge on GH secretion, producing a synergistic pulse 2–10 times greater than either agent alone.

Administration Routes

Subcutaneous injection

Intramuscular injection

Dosing Protocol

Typical Dose

200–300 mcg

Frequency

2–3x daily (or once before bed)

Cycle Length

8–16 weeks, with 4-week breaks

Administration

Subcutaneous injection

Protocol Notes

Best administered on an empty stomach. Bedtime administration aligns with natural GH pulse. Commonly combined with CJC-1295 No DAC for synergistic GH release.

Reconstitution Guide

Add 2 mL bacteriostatic water to 2 mg vial → 1000 mcg/mL For 300 mcg dose: draw 0.3 mL (30 units on U-100 syringe)

Storage Information

Lyophilized: refrigerate. Reconstituted: refrigerate and use within 30 days.

Quality & Sourcing Standards

When sourcing Ipamorelin for research purposes, the following quality benchmarks should be verified before use.

Purity:

>98% (verified by HPLC)

Certificate of Analysis (COA):

Must be provided by supplier

Endotoxin Testing:

<0.1 EU/mg (prevents bacterial contamination)

GMP Compliance:

Manufactured in cGMP-certified facility

Third-Party Testing:

Independent lab verification preferred

Storage Information

Lyophilized: refrigerate. Reconstituted: refrigerate and use within 30 days.

FDA Disclaimer

The statements made within this website have not been evaluated by the US Food and Drug Administration. The products and information provided are not intended to diagnose, treat, cure, or prevent any disease. This website is intended for educational and research purposes only. Many peptides described on this site are not approved by the FDA for human therapeutic use and are classified as research chemicals. Nothing on this site constitutes medical advice.

Research Highlights

1

Demonstrated selective GH release without cortisol elevation

2

Shown to increase bone mineral density in animal models

3

Phase II clinical trials completed for post-operative ileus

Evidence Level

Multiple animal studies and/or early human trials. Reasonable confidence in mechanism, but human data is limited.

Compatible Peptides

Peptides commonly used alongside Ipamorelin for synergistic effects.

BPC-157

A synthetic pentadecapeptide derived from gastric juice with extraordinary tissue healing properties across multiple organ systems.

CJC-1295 No DAC

A short-acting GHRH analog that produces physiological GH pulses when combined with a GHRP like Ipamorelin.

TB-500

A synthetic analog of Thymosin Beta-4 that promotes systemic healing through actin regulation and angiogenesis.

Protocols Featuring Ipamorelin

GH Optimization Protocol

Growth hormone optimization for body composition and recovery

Complete Recovery Stack

Comprehensive recovery from surgery or major injury

Quick Reference

Category

Hormone & GH

Status

Research Only

Dose

200–300 mcg

Frequency

2–3x daily (or once before bed)

Cycle

8–16 weeks, with 4-week breaks