Ipamorelin is a synthetic five-amino-acid peptide that triggers growth hormone release by acting on the ghrelin receptor. It reached phase 2 trials for gut recovery after bowel surgery but is not FDA-approved for any use.
Ipamorelin is a pentapeptide (five amino acids) made in the lab. It belongs to the growth hormone secretagogues: compounds that act on the ghrelin receptor in the pituitary and brain to trigger a pulse of growth hormone. It was found at Novo Nordisk in Denmark during a chemistry programme based on an older peptide, GHRP-1, and was described in 1998 as the first "selective" member of its family (Raun 1998).
"Selective" refers to an animal finding: in pigs, older peptides such as GHRP-6 and GHRP-2 also raised the stress hormones ACTH and cortisol, while ipamorelin raised growth hormone without a clear rise in those hormones, even at very high doses (Raun 1998). Novo Nordisk then ran a single-dose study in healthy men (Gobburu 1999).
Development later moved to Helsinn, which tested ipamorelin for postoperative ileus, the slow return of gut function after abdominal surgery. Rat studies supported the idea (Venkova 2009), but a phase 2 trial in 114 bowel surgery patients found no significant benefit over placebo (Beck 2014). A second, larger phase 2 trial (NCT01280344, 320 participants, sponsored by Helsinn) is listed as completed on ClinicalTrials.gov, but we could not find published results. Ipamorelin was never approved.
Type: synthetic peptide, 5 amino acids (a ghrelin receptor agonist).
Studied for: growth hormone release, bone growth in rats, and gut recovery after surgery.
Strongest evidence: one phase 2 trial in surgical patients, which did not meet its main goal. The rest is animal work and a single-dose study in healthy men.
Legal status: not approved as a medicine in the US; prohibited in sport by WADA.
02
Ipamorelin protocols and supplies
Schedules reported for this peptide, with the syringe measure for each step and the supplies each one takes. Reported use is not evidence that a schedule works or is safe, and none of this is medical advice.
Gradual, once daily (often at bedtime)
Subcutaneous injection, once a day
Community-reported
Reported in the research community. It has not been tested as a schedule in human trials. Worked out with a 10 mg vial + 3 mL bacteriostatic water (3.33 mg/mL, 33.3 mcg per unit).
Amounts as reported, with the syringe or spray measure for the vial below. Not a recommendation.
Period
Amount each time
U-100 units
Volume
Weeks 1-2
100 mcg
3
0.03 mL
Weeks 3-4
150 mcg
4.5
0.05 mL
Weeks 5-8
200 mcg
6
0.06 mL
Week 9 on
250 mcg
7.5
0.08 mL
Minimum supplies, worked out from the amounts above. Add a margin for losses.
Item
8 weeks
12 weeks
16 weeks
Injections
56
84
112
Total peptide
9.1 mg
16.1 mg
23.1 mg
Ipamorelin vials (10 mg)
1
2
3
Bacteriostatic water
3 mL
6 mL
9 mL
Water bottles (10 mL)
1
1
1
U-100 insulin syringes
56
84
112
Alcohol swabs (boxes of 100)
112 (2)
168 (2)
224 (3)
03
Ipamorelin doses used in studies
The dose each published study gave its participants, copied from the paper. Not dosing instructions; animal doses do not convert directly to people.
At a glance: 10 studies report a dose (2 in people, 8 in animals).
Doses used in human studies
Gobburu JV 1999: 4.21, 14.02, 42.13, 84.27 or 140.45 nmol/kg over 15 minutes (single dose; 8 men per dose level) (Intravenous infusion over 15 minutes; Single dose)
Beck DE 2014: 0.03 mg/kg twice daily, from postoperative day 1 to day 7 or hospital discharge (Intravenous infusion, twice daily; Up to 7 days)
Every study
Doses as reported by each study. Not a recommendation.
In vitro (rat pituitary cells) and intravenous in rats and pigs
Dose-response ranges in rats and pigs; ED50 for growth hormone release 80 nmol/kg in rats and 2.3 nmol/kg in pigs. Selectivity was tested at doses over 200 times the ED50.
Not applicable (laboratory analysis of seized products)
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04
Evidence at a glance
What has been studied, by type of evidence. A result in animals or cells is a reason to study something in people, not proof that it works in people.
In humans
Summarised
Two published human studies exist. Neither looked at body composition, muscle, sleep or ageing, which are the uses often claimed online:
Healthy volunteers: healthy men received a single 15-minute intravenous infusion at one of five dose levels (8 men per level). Each dose produced one pulse of growth hormone that peaked at about 40 minutes and then faded; ipamorelin itself had a half-life of about 2 hours (Gobburu 1999).
Bowel surgery: in a double-blind phase 2 trial, 114 adults recovering from bowel resection received intravenous ipamorelin or placebo twice daily for up to 7 days. Time to tolerating a solid meal was 25.3 hours with ipamorelin and 32.6 hours with placebo, a difference that was not statistically significant. Side effect rates were similar in both groups (Beck 2014).
In short: ipamorelin has been given to people only briefly, by vein, in controlled settings. We could not find any published controlled trial of it given under the skin over weeks or months, so its effects and safety with longer use are unknown.
In animals
Summarised
Growth hormone release
In rat pituitary cells, anaesthetised rats and conscious pigs, ipamorelin released growth hormone about as strongly as GHRP-6. Blocking the GHRP receptor stopped the effect, showing it works through that receptor (Raun 1998).
Bone and body growth
In adult female rats, 15 days of injections increased the growth rate of the shin bone and body weight in a dose-dependent way, without changing total IGF-1 in the blood (Johansen 1999). Over 12 weeks, rats on continuous ipamorelin had more bone mineral, but because their bones were larger, not denser (Svensson 2000). In rats given high-dose steroids, adding ipamorelin offset part of the loss in muscle strength and bone formation (Andersen 2001). Most of this bone work was done by or with Novo Nordisk.
Gut movement after surgery
In rats that had abdominal surgery, repeated intravenous doses increased stool output, food intake and weight gain over 48 hours (Venkova 2009), and a single dose sped up stomach emptying (Greenwood-Van Meerveld 2012). These results did not carry over into a clear benefit in the human trial (Beck 2014).
How the body handles it
In male rats, ipamorelin was cleared from the blood about five times more slowly than GHRP-6, was mostly removed in urine, and was largely excreted intact. About 20% was absorbed when given into the nose (Johansen 1998).
In cells (in vitro)
Nothing yet
No summary in our library yet. We only publish one after checking it against the original papers.
Proposed mechanisms from cell and animal studies. A plausible mechanism is not evidence of an effect in people.
Ipamorelin mimics ghrelin, a hormone made mainly in the stomach. The proposed pathways come from cell, animal and short human studies:
Ghrelin (GHRP) receptor in the pituitary: it releases growth hormone through the same receptor as GHRP-6; a GHRP blocker stopped the effect in rat pituitary cells (Raun 1998).
Pulse-like release: in healthy men a single dose gave one short burst of growth hormone, not a sustained rise (Gobburu 1999).
Selectivity: in pigs it did not raise ACTH, cortisol, prolactin or the other pituitary hormones measured (Raun 1998). We could not find published human data testing this.
Gut muscle: in stomach tissue from operated rats it restored contractions through the ghrelin receptor and nerve signalling that uses acetylcholine (Greenwood-Van Meerveld 2012).
06
Reconstitution
How concentration changes with the amount of liquid added. A U-100 insulin syringe holds 1 mL in 100 units, so each unit is 0.01 mL. Step-by-step guide.
Step by step
Wash your hands and work on a clean, uncluttered surface. Let a refrigerated vial reach room temperature so the stopper is easier to pierce.
Wipe the rubber stopper of the peptide vial and of the bacteriostatic water with a fresh alcohol swab, and let them air-dry.
Draw the chosen volume of bacteriostatic water into a sterile syringe. With 2 mL, a 10 mg vial ends up at 5,000 mcg/mL, or 50 mcg per U-100 unit.
Insert the needle through the stopper and let the water run slowly down the inside wall of the vial, not straight onto the powder.
Swirl or roll the vial gently until the powder dissolves. Do not shake it: foaming can damage some peptides.
Check the solution against the light. It should be clear; cloudiness or particles mean something is wrong with the vial or the water.
Write the date and the volume of water on the label. Every unit calculation later depends on that volume.
Store the reconstituted Ipamorelin vial in the refrigerator, away from light.
Concentration by volume
A 10 mg vial: concentration after adding the liquid, and how much peptide each U-100 unit (0.01 mL) holds.
Arithmetic only. It assumes the vial holds exactly what the label says.
Concentration
5,000 mcg/mL
Per U-100 unit
50 mcg
Volume for your amount
—
07
Measuring with a U-100 syringe
What each mark on an insulin syringe holds once the vial is mixed. This is arithmetic, not a dose.
Reading a U-100 syringe: how much peptide each mark holds in a 10 mg vial mixed with 2 mL. Not a dose.
Syringe mark
Volume
Peptide in that volume
5 units
0.05 mL
250 mcg
10 units
0.1 mL
500 mcg
20 units
0.2 mL
1 mg
25 units
0.25 mL
1.25 mg
50 units
0.5 mL
2.5 mg
100 units
1 mL
5 mg
A U-100 insulin syringe holds 1 mL in 100 units, so each unit is 0.01 mL. The marks measure volume, not peptide.
Syringes come in 0.3 mL (30 units), 0.5 mL (50 units) and 1 mL (100 units) sizes. The smaller ones have finer marks and are easier to read for small volumes.
Read the volume at the top edge of the plunger's rubber seal, at eye level.
Tap out air bubbles before reading: a bubble takes up volume and makes the reading wrong.
Use a new sterile syringe and needle every time, and dispose of them in a sharps container.
08
Supplies
What reconstituting and measuring a vial takes.
The peptide vial, with its certificate of analysis (COA) for that batch. See how to read a COA.
Bacteriostatic water (water with 0.9% benzyl alcohol), which keeps a multi-use vial from growing bacteria. Sterile water has no preservative.
Sterile syringes to add the water, and U-100 insulin syringes to measure.
Alcohol swabs for the stoppers.
A sharps container for used needles.
A label or marker to write the date and the volume of water on the vial.
09
Side effects, safety and legal status
Published human safety data cover single intravenous doses in healthy men and up to 7 days of intravenous use in hospital, where side effects were similar to placebo (Beck 2014). Nothing is known from controlled studies about repeated injections under the skin over months.
Product quality: ipamorelin sold online is not checked by any regulator. Doping control labs have found unexpected variants in black market products, including a modified form with an extra amino acid (Gly-ipamorelin) (Krug 2018).
Growth hormone effects: raising growth hormone over the long term can affect blood sugar, fluid balance and cell growth. These effects have not been studied for ipamorelin specifically.
Animal selectivity is not human proof: the "no cortisol rise" finding comes from pigs.
Injection risks: any injected product that is not sterile can cause infection or abscesses.
Sport: growth hormone secretagogues are on the WADA prohibited list at all times.
FDA
Not FDA-approved for any use.
WADA
Prohibited at all times (growth hormone secretagogues).
Status checked on
Oct 26, 2026
10
Storing Ipamorelin
Before mixing
Freeze-dried (lyophilised) peptide is the most stable form. It is usually kept refrigerated, or frozen for long storage, sealed and away from light.
Heat, moisture and light speed up degradation. Keep the vial in its box and avoid leaving it in a car or by a window.
After mixing
Keep the reconstituted vial refrigerated and away from light. Do not freeze it again: freezing and thawing a solution can break the peptide down.
How long a mixed vial stays good depends on the peptide and the diluent, and for most research peptides there is no published stability data. Follow the supplier's guidance and discard any vial that turns cloudy.
Pierce the stopper as few times as possible, and always with a new sterile needle after wiping it with alcohol.
Write the volume of water on the label (for example "2 mL"). Without it, the unit calculations cannot be checked later.
11
Questions about Ipamorelin
Is Ipamorelin FDA-approved?
Not FDA-approved for any use.
What doses of Ipamorelin have been studied?
Our library has 10 studies on Ipamorelin. The doses each one used are in section 03, next to the study. They are not dosing instructions.
How much Ipamorelin is in each syringe unit?
It depends on how much liquid is added to the vial. For a 10 mg vial with 2 mL, each U-100 unit holds 50 mcg. The reconstitution table and calculator work it out for other volumes.
Has ipamorelin been tested in clinical trials?
Yes, but only for one use. A phase 2 trial gave it by vein to patients recovering from bowel surgery and found no significant benefit over placebo. A second phase 2 trial is listed as completed, but we could not find its results. There are no published trials for muscle, fat loss or ageing.
Why is ipamorelin called selective?
In pig studies it raised growth hormone without raising the stress hormones ACTH and cortisol, unlike older peptides of the same family. This has not been confirmed in published human studies.
Does ipamorelin raise IGF-1?
In a 15-day rat study it increased bone growth without changing total IGF-1 in the blood. The published human studies measured growth hormone after single doses, not IGF-1 over time.
How much bacteriostatic water goes into a 10 mg Ipamorelin vial?
There is no single correct volume: it only changes the concentration. For a 10 mg vial, 1 mL gives 10,000 mcg/mL, 2 mL gives 5,000 mcg/mL, 3 mL gives 3,333 mcg/mL. More water makes small amounts easier to measure; less water keeps volumes small. Whatever volume is used, write it on the label.
What does one unit on an insulin syringe mean?
On a U-100 syringe, 100 units = 1 mL, so one unit is 0.01 mL. How much peptide that holds depends on the concentration of the vial, which depends on how much water was added.
Can doses from animal studies of Ipamorelin be converted to people?
No. Animal doses are reported per kilogram for a different species, and scaling them to people is not reliable. That is why Upzo shows each study dose next to its study, unconverted.
How should Ipamorelin be stored?
Unopened freeze-dried vials are usually kept refrigerated and away from light. Once mixed, keep the vial refrigerated and follow the supplier's guidance on how long it lasts.
12
References
Ipamorelin, the first selective growth hormone secretagogue. Raun K, Hansen BS, Johansen NL, et al. European Journal of Endocrinology. 1998;139:552-561. doi:10.1530/eje.0.1390552
Pharmacokinetic evaluation of ipamorelin and other peptidyl growth hormone secretagogues with emphasis on nasal absorption. Johansen PB, Hansen KT, Andersen JV, et al. Xenobiotica. 1998;28:1083-1092. doi:10.1080/004982598238976
Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers. Gobburu JV, Agersø H, Jusko WJ, et al. Pharmaceutical Research. 1999;16:1412-1416. doi:10.1023/a:1018955126402
Ipamorelin, a new growth-hormone-releasing peptide, induces longitudinal bone growth in rats. Johansen PB, Nowak J, Skjaerbaek C, et al. Growth Hormone & IGF Research. 1999;9:106-113. doi:10.1054/ghir.1999.9998
The GH secretagogues ipamorelin and GH-releasing peptide-6 increase bone mineral content in adult female rats. Svensson J, Lall S, Dickson SL, et al. Journal of Endocrinology. 2000;165:569-577. doi:10.1677/joe.0.1650569
The growth hormone secretagogue ipamorelin counteracts glucocorticoid-induced decrease in bone formation of adult rats. Andersen NB, Malmlöf K, Johansen PB, et al. Growth Hormone & IGF Research. 2001;11:266-272. doi:10.1054/ghir.2001.0239
Efficacy of ipamorelin, a novel ghrelin mimetic, in a rodent model of postoperative ileus. Venkova K, Mann W, Nelson R, et al. Journal of Pharmacology and Experimental Therapeutics. 2009;329:1110-1116. doi:10.1124/jpet.108.149211
Efficacy of ipamorelin, a ghrelin mimetic, on gastric dysmotility in a rodent model of postoperative ileus. Greenwood-Van Meerveld B, Tyler K, Mohammadi E, et al. Journal of Experimental Pharmacology. 2012;4:149-155. doi:10.2147/JEP.S35396
Prospective, randomized, controlled, proof-of-concept study of the Ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients. Beck DE, Sweeney WB, McCarter MD, et al. International Journal of Colorectal Disease. 2014;29:1527-1534. doi:10.1007/s00384-014-2030-8
Analysis of new growth promoting black market products. Krug O, Thomas A, Malerød-Fjeld H, et al. Growth Hormone & IGF Research. 2018;41:1-6. doi:10.1016/j.ghir.2018.05.001
Research supplier
For laboratory research use only.
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Research and education only. Not medical advice. Many peptides on this site are not approved by the FDA for human use. Doses shown are the ones used in published studies and are not a recommendation. Talk to a licensed clinician before using any of them. Read the full disclaimer.
