Growth hormone axis
Ipamorelin
Also called Ipamorelin acetate, NNC 26-0161
Ipamorelin is a small lab-made peptide (five building blocks) that copies the hunger hormone ghrelin to make the pituitary release growth hormone. It was tested in people for gut slowdown after surgery but did not clearly work and was never approved. It is popular in wellness circles, often paired with CJC-1295.
Overview
Ipamorelin is a small lab-made peptide (five building blocks) that copies the hunger hormone ghrelin to make the pituitary release growth hormone. It was tested in people for gut slowdown after surgery but did not clearly work and was never approved. It is popular in wellness circles, often paired with CJC-1295.
How it works
Established: ipamorelin activates the ghrelin receptor (GHS-R1a) on the pituitary, causing growth hormone release. It is described as more selective than older GHRPs, with less effect on cortisol and prolactin in early studies (proposed/preclinical). Ghrelin-receptor activation also speeds gut movement, which was the rationale for testing it in postoperative ileus.
What research shows
- Beck 2014, phase 2 double-blind RCT (n=114 analysed) after bowel resection: median time to first tolerated meal 25.3 h vs 32.6 h on placebo (p=0.15, not significant); no significant secondary endpoints.
- Gobburu 1999, randomized placebo-controlled IV dose-escalation PK/PD study in healthy men: half-life about 2 hours; no adverse events reported (as summarized by FDA).
- FDA's 2024 review found no effectiveness data for GH deficiency or postoperative ileus, and no data for the subcutaneous route used in compounding.
Doses studied in people
| Study or label | Dose used | Source |
|---|---|---|
| Phase 2 RCT, postoperative ileus after bowel resection (n=114 analysed; NCT00672074) | 0.03 mg/kg IV twice daily from post-op day 1 for up to 7 days | 2 |
| Phase 1 PK/PD study, healthy men (Gobburu 1999, as summarized by FDA) | Single 15-minute IV infusions, 4.21–140.45 nmol/kg | 1 |
Published human doses are intravenous only; no published trial data exist for the subcutaneous doses circulating online.
Read this first: these are the amounts given to participants in published studies or written on official prescribing labels, reported for reference. They are not recommendations. Trial doses were chosen for specific patients under medical supervision, and a dose that is safe in one person can be harmful in another.
Weekly protocol
How the schedule looks week by week. Each chart says where it comes from: a prescribing label, a clinical trial, or a protocol commonly reported online.
Phase 2 postoperative ileus trial (Beck 2014)
Clinical trialOne week
Twice daily · Intravenous infusion
Dose by week
Commonly reported protocol
Commonly reported, not studiedOne week
Once daily, 30–60 minutes before bed on an empty stomach · Subcutaneous injection
Syringe units (U-100)
Dose by week
Supplies for one course (estimate)
Counts only. This site does not sell or link to supplies.
Reference only, not a recommendation. Charts marked "commonly reported" describe what public sources say people use. They have not been tested in trials, and their safety and effect are unknown. Label and trial schedules were set for specific patients under medical supervision. Use the calculator only to understand the arithmetic.
Vial math
Many research vials hold 5 or 10 mg of powder. This table shows how much ends up in each mark on a U-100 insulin syringe for common amounts of added liquid. It is arithmetic only, not a dose.
| Vial | Liquid added | Concentration | Per unit (0.01 mL) | |
|---|---|---|---|---|
| 5 mg | 1 mL | 5 mg/mL | 50 mcg | Open in calculator |
| 5 mg | 2 mL | 2.5 mg/mL | 25 mcg | Open in calculator |
| 5 mg | 3 mL | 1.67 mg/mL | 16.7 mcg | Open in calculator |
| 10 mg | 1 mL | 10 mg/mL | 100 mcg | Open in calculator |
| 10 mg | 2 mL | 5 mg/mL | 50 mcg | Open in calculator |
| 10 mg | 3 mL | 3.33 mg/mL | 33.3 mcg | Open in calculator |
More sizes: all vial sizes · How this works: Syringes and units · Reconstitution guide.
Safety
- In the phase 2 ileus trial, treatment-emergent adverse events occurred in 87.5% (ipamorelin) vs 94.8% (placebo); described as well tolerated.
- FDA cites immunogenicity risk for injectable compounded forms and reports of serious adverse events including death with IV use.
- FDA notes limited nonclinical data suggesting possible reinforcing/addictive properties and effects on reproduction.
- Unknown long-term safety.
Report side effects of any drug or product to the FDA through MedWatch. For a possible poisoning in the US, call Poison Control at 1-800-222-1222.
Legal status
- FDA
- Not FDA-approved
- Compounding
- 503A: placed in Category 2 in Sept 2023; FDA PCAC voted 0–12 (1 abstain) on Oct 29, 2024 against adding either form to the 503A bulks list. FDA now lists the 503A nomination as 'withdrawn' (not on the May 2026 503A categories list), so it is not eligible for 503A compounding. 503B: still Category 2 (since Sept 29, 2023). Not part of the April 2026 removals, the July 2026 PCAC review, or the five peptides slated for review by Feb 2027.
- Sports (WADA)
- Prohibited at all times (S2.2.4 growth hormone secretagogues; named)
- Other
- FDA issued warning letters to online peptide vendors in Aug 2026 rejecting 'research use only' labeling.
Rules change often. See Legal status of peptides for how these categories work.
History
Synthesized at Novo Nordisk in the mid-1990s and described in 1998. A 1999 PK/PD study in healthy men measured its GH response and ~2-hour half-life. A phase 2 trial in bowel-surgery patients (published 2014) failed its main endpoint, and the compound was not developed further.
Common questions
Is ipamorelin FDA-approved?
No. A phase 2 trial in bowel-surgery patients did not meet its main goal, and the compound was not developed further 2.
What does the research show?
What doses were studied in people?
Is ipamorelin safe?
Can ipamorelin be compounded?
Is ipamorelin banned in sport?
Yes. WADA's 2026 list prohibits it at all times as a growth hormone secretagogue and names it 8.
Sold in blends and stacks
Related compounds
CJC-1295
CJC-1295 with DAC · CJC-1295 without DAC
CJC-1295 is a lab-made, modified version of the active part of growth-hormone-releasing hormone.
GHRP-2
Pralmorelin · KP-102
GHRP-2 is a small synthetic peptide that strongly triggers growth hormone release by acting on the ghrelin receptor.
GHRP-6
Growth hormone releasing peptide-6 · SKF-110679
GHRP-6 is one of the first synthetic peptides found to release growth hormone through what was later named the ghrelin receptor.
Hexarelin
Examorelin · EP-23905
Hexarelin is a synthetic growth hormone-releasing peptide closely related to GHRP-6.
MK-677 (Ibutamoren)
Ibutamoren mesylate · MK-0677
MK-677 (ibutamoren) is a pill, not a peptide, that copies ghrelin to raise growth hormone and IGF-1.
Sources
- FDA briefing document, PCAC Oct 29, 2024: ipamorelin and ipamorelin acetate Regulatory
- Beck DE et al. Prospective, randomized, controlled, proof-of-concept study of the ghrelin mimetic ipamorelin for postoperative ileus in bowel resection patients. Int J Colorectal Dis 2014;29:1527-34 Journal
- ClinicalTrials.gov NCT00672074: Safety and Efficacy of Ipamorelin for Management of Post-Operative Ileus ClinicalTrials.gov
- FDA PCAC October 29, 2024 final summary minutes (ibutamoren, ipamorelin, kisspeptin-10, L-theanine votes) Regulatory
- FDA: Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (content current as of 04/22/2026) Regulatory
- FDA: Bulk Drug Substances Nominated for Use in Compounding Under Section 503A (categories list, updated May 14, 2026) Regulatory
- FDA: Bulk Drug Substances Nominated for Use in Compounding Under Section 503B (categories list, updated March 21, 2025) Regulatory
- WADA 2026 Prohibited List (in force 1 January 2026) Regulatory
- Holland & Knight: Peptides at a Crossroads - HHS and FDA actions (Oct 2026) Regulatory
Last reviewed 2026-10-25 · How we research · Found an error? See our corrections policy.