Ipamorelin
/ip-ah-MOR-eh-lin/aka Ipamorelin acetate, Ipa
A five-amino-acid ghrelin-receptor agonist that triggers a short GH pulse, with little effect on cortisol or prolactin in animal studies.
Ipamorelin: educational research discussion. Not medical advice. Not a protocol for you.Details
- Reported range
- 100–300 mcg
- Frequency
- 1–3× daily
- Cycle length
- 8–12 week blocks, then a break
- Half-life
- ≈ 2 h
- Route
- SC
Reported figures describe what is published or discussed. None of them is a dose for you.
Mechanism
What it is proposed to do
Ipamorelin binds the growth hormone secretagogue receptor (GHS-R1a), the ghrelin receptor, in the pituitary and hypothalamus. That triggers a single GH pulse; in a human IV study, GH peaked at about 40 minutes and fell back to negligible levels. In rats and pigs it released GH without raising ACTH or cortisol above GHRH-like levels, even at more than 200 times the effective dose, unlike GHRP-6 and GHRP-2. Human data on that selectivity are much thinner.
- 01
Ipamorelin
Pentapeptide; ~2 h half-life after IV dosing in humans
established - 02
Ghrelin receptor (GHS-R1a)
Pituitary and hypothalamus
established - 03
GH pulse ↑
Single pulse, peak ~40 min in healthy men
established - 04
Cortisol and prolactin spared
Shown in rats and pigs; human data limited
proposed
Half-life. About 2 hours after IV dosing in healthy men (1999). The GH pulse it triggers is over within a few hours.
Dosing & cycles
What is reported, and where it comes from
Numbers below are labeled FDA label, clinical trial range or commonly reported range. They describe the published and discussed landscape. They are not instructions and not a protocol for you.
Dosing studio
Every figure is labeled by where it comes from.
Scale view: Commonly reported SC range
Probe at 200 mcg: inside the reported band (100–300 mcg). Drag it to read the scale. It does not pick a number for you.
Typical cycle, as a calendar
Community pattern: 5 on / 2 off with CJC
8–12 week blocks
Weekday injections alongside CJC-1295 (no DAC), weekends off, then a break. The pattern is secretagogue-culture habit, not derived from ipamorelin data.
Cycle patterns
Community pattern: 5 on / 2 off with CJC
Weekday injections alongside CJC-1295 (no DAC), weekends off, then a break. The pattern is secretagogue-culture habit, not derived from ipamorelin data.
Community pattern: daily block
Daily injections for a fixed block, then time off. No human study shows that breaks are needed or that they help.
Stacks
What it gets combined with
Why people pair things, and what nobody has tested.
CJC-1295 (no DAC) + ipamorelin
2 compounds- Why people combine these
- The classic pair. Ipamorelin triggers the GH pulse through the ghrelin receptor; a GHRH analog amplifies it through a different receptor. Older human studies (GHRP-6 with GHRH) showed synergy between the two classes.
- Caution
- No trial has tested this pair. Stacking GH triggers stacks hunger, fluid-retention and glucose concerns too.
- What is unknown
- No published human data on this combination: dosing, interactions and long-term effects are all unstudied.
Tesamorelin + ipamorelin
2 compounds- Why people combine these
- Swaps the gray-market GHRH analog for an approved one, keeping the two-receptor logic.
- Caution
- Still untested as a pair, and it takes an approved drug outside its studied use.
- What is unknown
- No published human data on this combination: dosing, interactions and long-term effects are all unstudied.
Also sold in pre-mixed blends
What a blend changesIn a blend, Ipamorelin cannot be adjusted on its own, and the mixture has no human data of its own. Typical vial formats shown; labels vary.
Evidence
How much of this is known
Evidence grade
C
Thin human data
Human data thin (pilots, uncontrolled, or none completed). Strong animal data and a lot of anecdote.
How we gradeHuman pharmacokinetic data and one negative Phase 2 trial. The selectivity story comes from animal studies. Nothing tests the popular uses.
Human trial status
A 1999 dose-escalation study in healthy men characterized its pharmacokinetics: about a 2-hour half-life and a single GH pulse peaking near 40 minutes at every dose tested. A Phase 2, placebo-controlled trial in 117 bowel-resection patients (published 2014) found no significant benefit on time to first tolerated meal, and development stopped. There are no published trials for body composition, sleep or ageing.
Limitations
- The one efficacy trial was negative, in a hospital setting unrelated to popular use.
- Selectivity data (no cortisol or prolactin rise) come from rats and pigs.
- Doses discussed online are not derived from any human efficacy trial.
- FDA advisers voted 0–12 (1 abstention) against compounding it in October 2024.
Sources to read
- Raun K et al. Ipamorelin, the first selective growth hormone secretagogue (Eur J Endocrinol 1998)
- Gobburu JV et al. Pharmacokinetic-pharmacodynamic modeling of ipamorelin in human volunteers (Pharm Res 1999)
- Beck DE et al. Ghrelin mimetic ipamorelin for postoperative ileus in bowel resection patients: randomized proof-of-concept study (Int J Colorectal Dis 2014)
- Bowers CY et al. GH-releasing peptide stimulates GH release in normal men and acts synergistically with GHRH (JCEM 1990)
- FDA Pharmacy Compounding Advisory Committee, October 29, 2024
Links open PubMed, DailyMed, FDA or trial-registry searches. We do not cite what we have not described accurately.
Safety
Side effects, cautions, status
Commonly reported effects
- In the Phase 2 ileus trial, adverse events were no more common than on placebo (87.5% vs 94.8%, in post-surgical patients).
- Increased hunger is commonly reported, as expected from a ghrelin-receptor agonist, and usually described as milder than with GHRP-6.
- Also reported: water retention, headache and injection-site reactions.
- Raised GH can reduce insulin sensitivity; blood glucose changes are a class concern.
- Animal selectivity for GH over cortisol and prolactin is often cited as proof of safety. It is not a human long-term safety record.
Who should be extra cautious
- Active or past cancer. Raises GH and, downstream, IGF-1, a growth signal. No human safety data in this group.
- Diabetes or prediabetes. GH elevation can worsen insulin sensitivity.
- Pregnancy or breastfeeding. No data.
- Tested athletes. Prohibited at all times (WADA S2.2.4, named).
- Gray-market product. Purity, dose accuracy and endotoxin vary between vendors and batches.
Legal & regulatory status
Not approved anywhere. Discovered at Novo Nordisk and later tested by Helsinn for postoperative ileus, where it did not beat placebo and development stopped. In October 2024 an FDA advisory committee voted 0–12 (1 abstention) against adding it to the 503A bulks list.
2026 compounding context. Ipamorelin was not among the peptides in FDA's April 2026 Category 2 changes or the July 2026 advisory committee review. The October 2024 vote against it is the most recent formal review we found.
WADA. Prohibited at all times as a growth hormone secretagogue (S2.2.4). Ipamorelin is named on the list.
Storage & handling, high level
Sold as lyophilized powder. Reconstituted peptides are generally kept refrigerated, away from light, and degrade over weeks. Sterile technique and product quality matter more than any number on this page.
Reconstitution and injection technique are clinical skills. The reconstitution calculator does arithmetic only.
FAQ
Questions people ask about Ipamorelin
Why is ipamorelin called selective?
Did it ever work in a human trial?
Why pair it with CJC-1295?
Does it cause hunger?
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