Ipamorelin
Also known as NNC 26-0161, Ipamorelin acetate
Ipamorelin is a pentapeptide that triggers growth hormone release through the ghrelin receptor without the cortisol, prolactin, or hunger spikes seen with older GHRPs. It is the most popular GHRP in the community, usually stacked with a GHRH analog.
Reviewed by the amino101 editorial team. , first published .
Quick start
What people commonly do. Not a prescription.- Typical dose
- 100 to 300 mcg
- How often
- 1 to 3 times daily
- Where
- Subcutaneous, belly or thigh
- Timing
- Empty stomach, most often right before bed; extra doses on waking or after training in three a day protocols; no food for 20 to 30 minutes after
- Effects timeline
- deeper sleep 1 to 2 weeks, IGF-1 rise on bloodwork by 4 weeks, recovery and body composition 2 to 3 months
- Storage
- Lyophilized in freezer or fridge away from light; reconstituted in fridge 2 to 8 C, use within 4 weeks
- Cycle length
- 8 to 16 weeks
- Break between
- a few weeks off, recheck IGF-1 before the next run
Overview
Ipamorelin is a five amino acid synthetic peptide developed by Novo Nordisk in the 1990s as a growth hormone secretagogue. It belongs to the GHRP family alongside GHRP-2, GHRP-6, and hexarelin, all of which act on the ghrelin receptor (GHS-R1a). What set ipamorelin apart in the original animal work was selectivity. At doses that released as much growth hormone as GHRP-6, it produced no meaningful rise in ACTH, cortisol, or prolactin, and in humans it does not cause the sharp hunger that GHRP-6 is known for.
Human trials were limited. Novo Nordisk ran Phase 1 and Phase 2 studies, including one in patients after abdominal surgery looking at whether ipamorelin could speed recovery of bowel function. The compound was well tolerated and produced dose dependent growth hormone release, but the ileus trial did not show a convincing benefit and development was dropped. There are no published long term studies on body composition, sleep, or aging in healthy adults, so most of what people report about it comes from community experience rather than controlled data.
The reason it dominates community protocols is the combination of a clean side effect profile and genuine synergy with GHRH analogs. On its own, ipamorelin produces a moderate growth hormone pulse. Paired with Mod GRF 1-29 or tesamorelin, the two pathways reinforce each other and release considerably more than either alone. That pairing, injected before bed on an empty stomach, is probably the single most common growth hormone protocol outside of prescription growth hormone.
How it works
Ipamorelin is an agonist at the growth hormone secretagogue receptor, the same receptor activated by the stomach hormone ghrelin. Activation in the pituitary raises intracellular calcium in somatotrophs and triggers growth hormone release, while activation in the hypothalamus increases GHRH output and reduces somatostatin, which amplifies the pulse. Unlike GHRP-6 and hexarelin, ipamorelin shows little activity at the pathways that drive ACTH and prolactin release, so cortisol stays flat. It also appears to have a weaker effect on the appetite circuits, which is why hunger is rarely reported. The growth hormone released then acts on the liver to raise IGF-1.
Where the research stands
Growth hormone releaseStrong evidence
- Dose dependent GH pulse. Human pilot studies in healthy men showed clear dose dependent growth hormone release after single subcutaneous doses.
- Selectivity over cortisol and prolactin. Rodent and pig studies, then human dosing, showed GH release without meaningful ACTH, cortisol, or prolactin rise.
- Synergy with GHRH analogs. Human pilot data on GHRP plus GHRH combinations show a pulse larger than the sum of either alone.
BoneEmerging
- Bone mineral content. A 12 week rodent study found increased bone mineral content in growing rats; no human bone data.
Sleep and recoveryEmerging
- Sleep depth. Community reports are consistent, and ghrelin receptor agonists increase slow wave sleep in small human studies, but ipamorelin itself has no sleep trial.
Body compositionEmerging
- Fat loss and lean mass. No human outcome trials; the expectation rests on mechanism and on trials of other secretagogues.
Postoperative ileusWeak or mixed
- Bowel recovery after surgery. A Phase 2 RCT was safe but missed its efficacy endpoint, and development stopped.
- rodentIpamorelin released growth hormone as potently as GHRP-6 in rats and pigs without raising ACTH or cortisol.
- human pilotSingle subcutaneous doses in healthy men produced dose dependent growth hormone release with no significant change in prolactin or cortisol.
- human RCTA Phase 2 trial of ipamorelin for postoperative ileus after bowel resection showed acceptable safety but did not reach its efficacy endpoint.
- rodentIpamorelin increased bone mineral content in growing rats over 12 weeks, mediated partly by growth hormone.
Rodent and in vitro mean no human data for that finding. Human pilot means small, often uncontrolled. Human RCT means randomized and controlled. Clinical means an approved drug with regulatory data.
Levels over time
Modeled from the half-life. Illustrative, not measured.A half-life of 2 h against dosing every 24 h means each dose has cleared before the next. Nothing stacks; you start from zero every time, and the tissue effect is what carries over.
The two hour half-life gives a clean pulse that has finished well before the next dose, which is why one to three doses a day are used and why it fits naturally with a short acting GHRH analog.
Ipamorelin dosage and protocols
Runs of 8 to 16 weeks with no loading phase are standard, followed by a few weeks off. Ghrelin receptor desensitization with intermittent dosing has not been shown to be a practical problem, so the break is mostly a convention paired with IGF-1 bloodwork.
| Goal | Dose | Frequency | Route |
|---|---|---|---|
| Solo nightly dose | 200 to 300 mcg | once daily before bed | Subcutaneous |
| Stacked with a GHRH analog | 100 mcg | once daily before bed, with 100 mcg Mod GRF 1-29 | Subcutaneous, same syringe |
| Three pulse protocol | 100 mcg | 3 times daily, on waking, after training, before bed | Subcutaneous |
| Recovery focus | 100 to 200 mcg | twice daily, after training and before bed | Subcutaneous |
Fasted dosing matters: eating within 30 minutes on either side of the injection blunts the pulse. Bedtime lines up with the natural nighttime growth hormone surge, and a post-training dose is common because somatostatin is low after exercise. When stacked with Mod GRF 1-29 or tesamorelin, both are injected at the same time.
100 mcg is near saturation for GH release; 200-300 mcg is common when used alone
Dose calculator
U-100 insulin syringeUnits are a volume on the syringe, not an amount of peptide. Concentration changes every time you change the water volume. The standalone calculator explains the math.
| Vial | Suggested water | Concentration | Low dose draw |
|---|---|---|---|
| 5 mg | 2 mL | 2.5 mg/mL | 4 units |
| 10 mg | 3 mL | 3.333 mg/mL | 3 units |
How to reconstitute Ipamorelin
- 1
Wash your hands and wipe the work surface. Swab both vial stoppers with alcohol and let them dry.
- 2
Pick the water volume with the calculator above and write it on the vial. The concentration means nothing without it.
- 3
Draw the bacteriostatic water into a mixing syringe.
- 4
Insert at an angle and let the water run down the inside wall. Never squirt it straight onto the powder.
- 5
Swirl gently or leave it to dissolve. Do not shake.
- 6
Label with the date and water volume. Store in the fridge at 2 to 8 C and use within about 4 weeks.
- 7
Unmixed vials keep for months in the fridge and longer in the freezer, sealed and out of light.
- Full walkthrough with syringe reading and site rotation: reconstitution guide.
- ✓White, fluffy cake
Lyophilized powder should look like a small white puck or fluffy cake at the bottom of the vial. That is a proper freeze-dry.
- ✓Clear after mixing
Once dissolved the solution should be water-clear with nothing floating in it.
- !Slight clumping
Small clumps that dissolve with gentle swirling are fine. Shipping compacts powder.
- ✕Collapsed or melted
Powder stuck to the sides, glassy, or shrunken means it got hot in transit. Contact the vendor.
- ✕Cloudy or particles
Persistent cloudiness or visible particles after mixing means degraded or contaminated product. Do not use it.
- Week 1 to 2
Brief flushing or lightheadedness after doses, noticeably deeper sleep and vivid dreams, maybe a small appetite bump.
- Week 2 to 4
Early side effects fade, recovery between sessions starts to feel quicker, slight water retention at higher doses.
- Week 4 to 8
IGF-1 measurably higher on bloodwork, skin and hair may look better, gradual changes in how the body holds fat.
- Week 8 to 16
Modest body composition change if training and diet are in place; the effect is gradual rather than dramatic.
Interactions and stacking
CJC-1295 (no DAC)synergistic
The standard pairing; GHRH receptor plus ghrelin receptor produces a pulse several times larger than either alone.
Tesamorelinsynergistic
Same GHRH plus GHRP synergy, using the analog with the strongest human evidence.
Sermorelinsynergistic
Turns a weak sermorelin pulse into a meaningful one through the second pathway.
CJC-1295 (DAC)compatible
Adds discrete pulses on top of the continuous DAC baseline; watch total IGF-1.
HGHcaution
Exogenous growth hormone suppresses the pituitary, so there is little left for a secretagogue to release.
Insulin and diabetes medicationscaution
Growth hormone pulses raise glucose in the hours afterward; monitor if you take anything that lowers blood sugar.
Corticosteroidscaution
Glucocorticoids increase somatostatin tone and shrink the growth hormone response.
Food and sugary drinks near the doseavoid
Insulin and free fatty acids after a meal blunt release, so the same dose taken fed does much less.
The standard pairing; GHRH plus GHRP gives a synergistic pulse several times larger than either alone.
Same synergy with a GHRH analog that has stronger human evidence for visceral fat reduction.
Adds sharp pulses on top of the continuous stimulation from the DAC version.
Safety
- ▲Headache, flushing, or lightheadedness shortly after a dose
- ▲Water retention and puffy hands at higher doses
- ▲Tingling in the fingers when stacked heavily
- ▲Mild appetite increase in some people
- ▲Injection site redness or itching
- ▲Drowsiness after daytime doses
- ▲Headache, flushing, and lightheadedness right after a dose are common early on and usually fade.
- ▲Water retention and tingling in the fingers can show up at higher doses or when stacked heavily.
- ▲Eating within 30 minutes on either side of a dose blunts the growth hormone response.
- ▲Avoid raising growth hormone and IGF-1 with any active or prior hormone sensitive cancer.
- ▲It is not as potent as GHRP-2 or hexarelin on its own; the selectivity comes with a smaller pulse.
- ■Numbness or carpal tunnel symptoms that persist after lowering the dose
- ■Fasting glucose or HbA1c rising on bloodwork
- ■IGF-1 above the reference range for your age
- ■A new lump, growth, or any cancer diagnosis
- ■Severe or persistent headaches
Community poll
Self-reported by visitors. Not clinical evidence.Ipamorelin: frequently asked
Why is ipamorelin considered the cleanest GHRP?
Because it releases growth hormone without the side effects that come with the older ones. GHRP-6 makes you ravenous, hexarelin raises cortisol and prolactin, and GHRP-2 does a bit of both. Ipamorelin leaves those hormones mostly alone at normal doses.
Do I need to stack it with CJC-1295?
You do not have to, but almost everyone does. The GHRH analog and the GHRP work through different receptors and the combined growth hormone pulse is much larger than either alone. Running ipamorelin solo gives a modest effect that many people find underwhelming.
Will it make me hungry?
Usually not, or only mildly. It acts on the ghrelin receptor so some people notice a small appetite bump, but it is nothing like GHRP-6. If hunger is a problem, ipamorelin is the GHRP to use.
How long does it take to see results?
Deeper sleep often shows up within a week or two. Body composition changes, better recovery, and skin improvements take 2-3 months of consistent use, and the effects are gradual rather than dramatic.
References
- Ipamorelin, the first selective growth hormone secretagogue. European Journal of Endocrinology, 1998
- Phase 2 study of ipamorelin for the management of postoperative ileus after bowel resection. Neurogastroenterology and Motility, 2014
- Effects of ipamorelin on bone growth and bone mineral content in rats. Growth Hormone and IGF Research, 2001