Ipamorelin

Ipamorelin is a synthetic pentapeptide (Aib-His-D-2-Nal-D-Phe-Lys-NH₂) and one of the most selective ghrelin receptor agonists studied for growth hormone release. It produces pulsatile GH secretion with minimal effects on cortisol, prolactin, or aldosterone — making it the cleanest GHRP profile in the class. Ipamorelin is not approved for any medical indication and is sold as a research-use-only compound by third-party laboratories.

Source: Ipamorelin, the first selective growth hormone secretagogue, Raun K., Hansen B.S., Johansen N.L., Thøgersen H., Madsen K., Ankersen M., Andersen P.H., Eur J Endocrinol, 1998

What is ipamorelin and how does the selective GHS mechanism work?

Ipamorelin is a pentapeptide ghrelin receptor agonist (GHS-R1a) that stimulates pituitary growth hormone release with high selectivity, avoiding the cortisol and prolactin elevations seen with less selective GHRPs like GHRP-6 or hexarelin. It does not bind the ghrelin receptor in the hypothalamic nuclei responsible for appetite stimulation to the same degree as GHRP-6, so it does not produce significant hunger effects. Half-life is approximately 2 hours, supporting multiple-daily-dose research protocols.

Evidence level: human Phase 2 (postoperative ileus, abandoned); preclinical mechanism extensive

What does the research show for ipamorelin?

Ipamorelin was developed by Novo Nordisk and reached Phase 2 human trials for postoperative ileus — sponsored by Helsinn Therapeutics (NCT00672074) — which were completed but did not lead to approval, and the program was not advanced and was discontinued for that indication. Subsequent research interest has focused on its clean GH-release profile for research protocols. In human pharmacokinetic studies, ipamorelin reliably produces dose-dependent GH spikes and modest IGF-1 elevation with daily-dose protocols. No Phase 3 efficacy trial for any indication has been published.

Source: A Phase II, Double-Blind, Placebo-Controlled, Multiple-Dose Study to Evaluate the Safety and Efficacy of Ipamorelin Compared to Placebo for the Management of Post-Operative Ileus in Patients, Helsinn Therapeutics (U.S.), Inc (lead sponsor), ClinicalTrials.gov, 2008 · Evidence level: phase 2 human (postoperative ileus, completed, not advanced); preclinical and Phase 1 PK extensive

How does ipamorelin compare to other ghrelin-receptor GHS peptides?

Ipamorelin is the most selective ghrelin-receptor GHS in the GHRP class — same mechanism family as GHRP-2, GHRP-6, and hexarelin, but with substantially cleaner side effect profile. The trade-off is GH-release magnitude: hexarelin produces the strongest single-dose GH spike, ipamorelin produces the cleanest spike.

What are the documented side effects of ipamorelin?

Ipamorelin's side effect profile is among the cleanest in the GHRP class — typically mild injection-site reactions and occasional transient flushing. Unlike other GHRPs, it does not produce significant cortisol or prolactin elevation, and appetite effects are minimal. Long-term safety in humans at sustained research-use dosing is unknown given the absence of completed long-duration trials.

Evidence level: phase 2 human safety data (postoperative ileus); long-term unestablished

What is the regulatory status of ipamorelin?

Ipamorelin is not approved for any medical indication anywhere in the world as of August 2026. The Phase 2 program for postoperative ileus — run by Helsinn Therapeutics — was discontinued; no other clinical program is currently advancing. For pharmacy compounding, ipamorelin acetate remains in Category 2 of the FDA's bulk-drug-substances evaluation — substances the FDA has flagged as potentially presenting significant safety risks — under the 503B outsourcing-facility route, as of August 2026. It has not moved to Category 1 (eligible for compounding), and it was not among the twelve peptides the FDA removed from Category 2 in April 2026, so descriptions of ipamorelin “moving to Category 1” are inaccurate. In sport, ipamorelin is prohibited at all times by the World Anti-Doping Agency as a growth-hormone secretagogue under Section S2.2.4 of the Prohibited List. Ipamorelin is sold strictly as a research-use-only compound by third-party laboratories. Regulatory context in are peptides legal regulatory status by country.

Sources: FDA 503A bulk drug substances (Category 1/2) page; FDA Announces Removal of 12 Peptides from Category 2 (nominations withdrawn by the nominators) and Schedules PCAC Meetings, Orrick (legal analysis of the FDA notice), via Orrick Insights; WADA Prohibited List (current year)

Why does ipamorelin vendor verification matter?

Ipamorelin is one of the most widely-sold research-grade GH peptides, and its small molecular size makes synthesis straightforward — but quality variance across vendors is still substantial. Some vendors mislabel longer-chain GHRP analogs as ipamorelin. Independent HPLC purity testing and mass spectrometry identity confirmation (expected MW 711.8 Da) are the meaningful purity signals. Guidance in how-to-test-peptides hub.

How does Peptigrity verify ipamorelin vendors?

Peptigrity collects independent third-party Certificates of Analysis for ipamorelin from shops' official channels and verifies each for authenticity before publishing. Because shops choose which COAs to publish, results reflect the batches shops have made public rather than every production batch — a selection bias we state openly. A community-funded Testing Grant to purchase and test vials anonymously is in development. Tests in the database come from independent labs such as Janoshik Analytical, Freedom Diagnostics, and Chromate.

Frequently asked questions

How can I verify an ipamorelin vendor is selling real product?

The only reliable purity signal is an independent third-party HPLC certificate of analysis from a lab the vendor does not own or pay. For ipamorelin specifically, mass spectrometry identity confirmation is particularly relevant — mislabeling with related pentapeptide GHRP analogs occurs in the market. COA interpretation in red flags in peptide certificates of analysis.

Is ipamorelin legal to purchase?

Ipamorelin is legal to purchase as a research chemical for laboratory use in most jurisdictions, but it is not approved for human consumption. Country breakdown in peptide legal status guide.

Will ipamorelin be FDA-approved?

No active clinical development program for ipamorelin exists as of August 2026 The Phase 2 postoperative-ileus program (Helsinn Therapeutics) was discontinued. FDA approval is unlikely without a renewed development effort by a pharmaceutical sponsor.

Does ipamorelin stack well with GHRH analogs like CJC-1295?

Mechanistically, ghrelin-receptor GHS peptides like ipamorelin and GHRH analogs like CJC-1295 without DAC act on complementary pathways — GHS amplifies GHRH-mediated pituitary signaling — and the combination has been a long-standing research-protocol convention. Peptigrity does not recommend specific stacking protocols; this is medical practice that requires physician oversight.

How can I tell ipamorelin apart from GHRP-2 or GHRP-6?

Pharmacologically by side effect profile — GHRP-2 and GHRP-6 produce mild cortisol/prolactin elevation and (for GHRP-6) substantial appetite stimulation; ipamorelin produces neither. Chemically by mass — ipamorelin's molecular weight (711.8 Da) differs from GHRP-2 (817.0) and GHRP-6 (873.0). Mass spectrometry distinguishes them definitively.

Does Peptigrity recommend an ipamorelin dose?

No. Ipamorelin is not approved for human consumption and Peptigrity is an independent review platform, not a medical authority. Research-use dosing in community protocols varies widely. Anyone considering use should consult a licensed physician.

This section is for educational and informational purposes only and does not constitute medical advice. Ipamorelin is not approved by the FDA or any other regulator for human use. Always consult a qualified healthcare provider before using any peptide or research compound. Peptigrity is an independent review platform and does not sell, endorse, or recommend specific products or vendors.