Ipamorelin
A uniquely selective growth hormone booster that tells your pituitary to release more GH without messing with your cortisol or other hormones—making it the 'clean' choice among growth hormone peptides.
Written by Michael Carroll — Owner, Director of Research · Reviewed by the Peptide Initiative Research Team · Editorial standards
Suggested dose
100 – 300 mcg
Compound profile
Scientific & efficacy data
Growth Hormone
Peptide profile
Moderate human trials
Ipamorelin
100 mcg per injection · Multiple times daily
Molecular formula
C38H49N9O5
- Mol. weight
- 711.85 g/mol
- CAS number
- 170851-70-4
- PubChem
- 9831659
- Developed · 1998
- Novo Nordisk Research Team
Novo Nordisk A/S (Denmark)
Amino acid sequence
Aib-His-D-2-Nal-D-Phe-Lys-NH2GH Selectivity
Selective for GH release over ACTH and cortisol in conscious swine, holding at doses 200-fold above the GH ED50 [1]. Never measured in humans — neither published human study assayed those hormones [2][3].
Recovery Support
No human study has tested ipamorelin for workout recovery, sleep or tissue repair. In the one controlled human trial, trouble sleeping was more common on ipamorelin than on placebo — about 1 in 9 versus about 1 in 19 (10.7% vs 5.2%) [3][6]. The repair evidence is in rats: three months of ipamorelin restored bone formation and muscle strength in rats given a steroid that suppresses both [4], and it sped gut transit in a rat model of post-surgical ileus [5].
Safety Profile
Human exposure is limited to short courses — a single 15-minute IV infusion in the 40-volunteer pharmacokinetic study [2], and up to 7 days IV in the one Phase 2 trial, where low potassium, insomnia and high blood sugar were all more frequent than on placebo [3][6]. There is no data on long-term use, and none on the subcutaneous route.
Dosing
How much do I take?
100 – 300 mcg
100 – 300 mcg
Covers all 3 documented dose levels · timing · dose-adjustment guidance.
Suitability
Is this right for me?
Best for muscle recovery and growth & anti-aging and vitality
Best for
Clean GH Boost Seekers
If you want the benefits of increased growth hormone without spiking cortisol or other stress hormones, Ipamorelin is uniquely selective. Unlike GHRP-2 or GHRP-6, it won't raise your cortisol levels even at doses 200 times higher than needed for GH release.
Recovery-Focused Athletes
Ipamorelin shines for athletes who want better recovery between training sessions. The GH boost helps repair muscle tissue faster, and since it doesn't mess with other hormones, you can use it consistently without the rollercoaster effects.
Anti-Aging Enthusiasts
Growth hormone naturally declines as we age, contributing to muscle loss, fat gain, and reduced vitality. Ipamorelin offers a gentle way to restore more youthful GH levels without the risks of actual HGH therapy.
Those Recovering from Steroid Use
Research shows Ipamorelin can help counteract the muscle and bone-weakening effects of glucocorticoid medications. If you've been on steroids for medical reasons, this peptide may help you rebuild what you've lost.
Consider alternatives if
Do not use if
Use with caution if
Not sure?
Compare Ipamorelin with similar peptides to find the best fit for your goals.
Administration
How do I use it?
Subcutaneous injection
Route
Subcutaneous injection (just under the skin)—quick, easy, and most effective for peptides like Ipamorelin
Best sites
Covers reconstitution · step-by-step technique · storage · a sample daily schedule.
Safety
Is it safe?
4 common side effects · 1 serious
Ipamorelin's main selling point is that it raises growth hormone without raising cortisol or ACTH — two stress hormones that similar peptides do raise.
That was shown in pigs, and it held even at doses more than 200 times higher than the amount needed to raise growth hormone [1]. It has not been checked in people. The two published human studies measured ipamorelin and growth hormone only; neither one assayed cortisol, ACTH or prolactin [2][3].
Most of what we know about safety in people comes from a single trial in patients recovering from bowel surgery. 114 people took part: 56 got ipamorelin through an IV for up to seven days, and 58 got a placebo.
Most side effects were mild to moderate, and were the kind you would expect after surgery [3]. Serious problems happened at about the same rate in both groups — roughly 1 in 6 either way (17.9% on ipamorelin, 15.5% on placebo).
But three things were more common on ipamorelin: low potassium in about 1 in 8 people versus about 1 in 30 on placebo (12.5% vs 3.4%), trouble sleeping in about 1 in 9 versus about 1 in 19 (10.7% vs 5.2%), and high blood sugar at discharge in about 1 in 7 versus about 1 in 12 (14.3% vs 8.6%) [6].
Two people taking ipamorelin died. Both had colon cancer surgery, and in both cases the surgical join in the bowel leaked afterward. Nobody on the placebo died.
The FDA says it is unclear whether those deaths had anything to do with ipamorelin — but it pointed to them, along with the potassium and blood sugar differences, when it recommended in October 2024 against letting pharmacies compound ipamorelin [6].
Ipamorelin has been tested in people more than most research peptides, and far less than an approved medicine.
There is early work measuring how it moves through the body — 40 healthy men across five dose levels, given by IV infusion, which is where the roughly 2-hour half-life comes from [2] — plus the one trial in surgery patients [3]. That trial did not work.
It was built to see whether ipamorelin got the gut moving again faster after surgery.
People on ipamorelin ate their first solid meal about 7 hours sooner — 25.3 hours versus 32.6 hours — but that difference was small enough that it could easily have been chance, and none of the other measures separated from placebo either. The company stopped developing it for that use [3].
The 1998 study behind the "selective" label was done in rat pituitary cells, in rats, and in pigs, not in people [1]. Ipamorelin is not approved for anything, and in October 2024 the FDA recommended against adding it to the list of substances pharmacies are allowed to compound [6].
Common side effects · experienced by some users
Mild headache
Some users experience headaches in the first few days to weeks. This usually relates to your body adjusting to increased GH pulses.
Management: Stay well-hydrated, start with lower doses, and it typically resolves within the first 1-2 weeks.
Injection site reactions
Redness, minor swelling, or itching at the injection site is normal and harmless.
Management: Rotate injection sites between belly, thigh, and arm. A cool compress can help. Usually fades within hours.
Water retention
Mild bloating or puffiness, especially in the first few weeks. This is a known GH effect that usually stabilizes.
Management: Reduce sodium intake, stay hydrated, and give your body 2-3 weeks to adjust. Consider slightly lower doses if significant.
Increased appetite
Ipamorelin activates the ghrelin receptor, which can stimulate hunger—the same receptor that makes your stomach growl.
Management: Plan your meals around injection times. This effect can actually be useful if you're trying to gain muscle and need to eat more.
Less common
These typically resolve with continued use or dose adjustment.
Stop and seek help if
- Any signs of allergic reaction—stop immediately and seek medical help
- Persistent carpal tunnel symptoms that worsen despite dose reduction
- Significant joint pain that interferes with daily activities
- Blood sugar control becomes significantly harder to manage
- Unusual swelling that doesn't resolve with lower doses
- Any side effect that feels serious or really concerns you
Ipamorelin is a research compound, not an FDA-approved medication. Never start, stop, or change your dosing without guidance from a qualified healthcare provider. This information is for educational purposes only—not medical advice.
With other peptides
- Safe:CJC-1295 (with or without DAC) — Excellent synergistic pairing. CJC-1295 provides the GHRH signal while Ipamorelin amplifies it through the ghrelin receptor. Inject together for best results.
- Safe:Sermorelin — Another great pairing. Both stimulate GH but through different mechanisms, creating a more robust natural GH pulse.
- Safe:BPC-157 — Safe to combine for enhanced recovery. BPC-157 handles tissue repair while Ipamorelin boosts overall GH for systemic recovery.
- Safe:TB-500 — Complementary for healing. Inject at different sites but can use on the same day.
- Safe:GHRP-6 — Usually redundant since both hit the ghrelin receptor. Ipamorelin is preferred for its selectivity. Using both together is unnecessary.
With medications
- Caution:Insulin — GH can affect insulin sensitivity. Diabetics need to monitor blood sugar closely and may need insulin adjustments. Consult your doctor.
- Caution:Diabetes medications (metformin, etc.) — GH affects glucose metabolism. Monitor blood sugar more frequently and inform your doctor.
- Safe:Thyroid medications — GH can affect T4 to T3 conversion. May need thyroid level monitoring if on thyroid replacement.
- Safe:Glucocorticoids (prednisone, etc.) — Actually potentially beneficial—research shows Ipamorelin can help counter steroid-induced muscle and bone loss. Discuss with your doctor.
- Safe:Blood pressure medications — Some users experience BP changes with GH peptides. Monitor blood pressure regularly.
With supplements
- Safe:Arginine — Can enhance GH release when taken separately. Some people take arginine at different times to compound effects.
- Safe:GABA — Safe to combine—GABA may support additional GH release, especially when taken before bed.
- Safe:Melatonin — Safe and potentially synergistic for sleep quality and nighttime GH release.
- Safe:High-dose glucose or carbs — Blood sugar spikes blunt GH release. Avoid carbs around injection times for best results.
Effectiveness
How do I know it's working?
Moderate human trials · first signs week 1-2
Evidence level
Moderate human trials
(Phase 1-2)
Regulatory status
Research compound
Onset of effects
Moderate
(1-2 weeks)
How it works
Think of your pituitary gland as a GH factory that's controlled by two signals: one that says 'make more!'
(GHRH) and one that says 'slow down!' (somatostatin). Ipamorelin works like pressing the gas pedal without also triggering the alarm system.
It binds to the ghrelin receptor (the same one that tells you you're hungry), which signals your pituitary to release growth hormone in natural pulses—just like your body does when you're young. What makes Ipamorelin special is that it ONLY does this one job.
Other similar peptides also accidentally boost stress hormones like cortisol, but Ipamorelin is laser-focused on GH alone.
The deeper mechanism
Ipamorelin (Aib-His-D-2-Nal-D-Phe-Lys-NH2) is a pentapeptide growth hormone secretagogue that selectively activates the growth hormone secretagogue receptor (GHS-R1a), also known as the ghrelin receptor.
Unlike endogenous ghrelin or other synthetic GHRPs (GHRP-6, GHRP-2, hexarelin), ipamorelin demonstrates remarkable selectivity for GH release without significant effects on ACTH, cortisol, prolactin, or aldosterone.
This selectivity was demonstrated at doses over 200-fold higher than the ED50 for GH release. The mechanism involves GHS-R1a activation on pituitary somatotrophs, triggering phospholipase C, IP3/DAG signaling, calcium mobilization, and ultimately exocytosis of GH-containing vesicles.
Additionally, GHS-R1a activation on hypothalamic neurons may inhibit somatostatin release, further amplifying the GH response.
The peptide exhibits dose-proportional pharmacokinetics with a terminal half-life of approximately 2 hours, clearance of 0.078 L/h/kg, and volume of distribution of 0.22 L/kg. The SC50 for half-maximal GH stimulation is 214 nmol/L with maximal GH production rate of 694 mIU/L/h.
What to expect
Week 1-2
What you might notice
- Possibly better sleep quality, especially with the bedtime dose
- Mild headache or injection site reactions (normal)
- Slight increase in appetite
- Some temporary water retention or bloating
What's normal
- Adjusting to the injection routine
- Minor side effects that resolve on their own
- No dramatic visible changes yet
What's next
- Continue consistent dosing timing
- Track any effects in a simple log
- Side effects typically improve by end of week 2
Week 3-4
What you might notice
- More consistent, deeper sleep
- Improved workout recovery—less soreness, faster bounce-back
- Side effects usually stabilize or resolve
- Possible subtle improvements in skin quality
What's normal
- Starting to feel the benefits
- Water retention typically stabilizes
- Getting into a comfortable routine
What's next
- Consider increasing dose if on starting protocol with no issues
- Continue tracking progress
- Focus on nutrition and training to maximize benefits
Week 5-8
What you might notice
- Noticeable improvements in body composition with proper diet/training
- Enhanced recovery becoming clearly apparent
- Better energy and vitality
- Improved skin elasticity and quality
- Potential fat loss, especially with caloric deficit
What's normal
- Steady, gradual improvements rather than dramatic changes
- Benefits compound with consistent use
- Most side effects resolved by now
What's next
- Continue through 8-12 week cycle
- Consider blood work to monitor IGF-1 and health markers
- Plan your next cycle or maintenance approach
Week 9-12+
What you might notice
- Peak benefits typically experienced
- Significant improvements in lean mass and fat loss with proper training
- Sustained energy and recovery improvements
- Possible plateau as your body adapts
What's normal
- Benefits stabilizing at their new baseline
- Some people cycle off for 4-8 weeks, others continue
- Considering whether to maintain, cycle off, or adjust
What's next
- Evaluate results and decide on next steps
- Some users take a 4-8 week break then resume
- Others continue with maintenance dosing
Signs it's working
Sleep and Recovery
- Falling asleep more easily at night
- Waking up feeling more refreshed and rested
- Deeper, more restorative sleep
- Faster recovery between workouts
- Less muscle soreness after training
Body Composition
- Gradual reduction in body fat, especially around the midsection
- Improved muscle tone and definition
- Better muscle pumps during workouts
- Clothes fitting differently (tighter in good places, looser around waist)
Skin and Appearance
- Improved skin elasticity and hydration
- Reduction in fine lines over time
- Healthier hair quality
- Overall more youthful appearance
Lab Markers (if tested)
- Elevated IGF-1 levels on blood work
- Stable or improved lipid profiles
- Maintained healthy blood sugar levels
Not seeing results? Common reasons
- Eating too close to injection—food, especially carbs, blunts GH release. Always inject fasted.
- Inconsistent dosing schedule—GH peptides work best with consistent timing to establish rhythmic release
- Poor quality peptide from unreliable source—always verify third-party testing certificates (COAs)
- Improper storage degraded the peptide—check that solution is crystal clear before using
- Unrealistic expectations—Ipamorelin provides gradual, natural improvements, not overnight transformations
- Not supporting with proper nutrition and exercise—peptides enhance your lifestyle, they don't replace it
- Blood sugar too high at injection time—insulin spikes inhibit GH release
Key research
Clinical trials
Tested in people
2 registered studies, none currently enrolling.
By phase
A trial spanning two phases is counted in both, so these can sum above the total. Observational studies carry no phase.
What kind of research
About 437 people took part in the studies that actually administered Ipamorelin. Observational studies analyse the records of people already taking it — nobody was given anything for the study, so they are counted separately and cannot show cause and effect.
Most recent
Safety and Efficacy of Ipamorelin Compared to Placebo for the Recovery of Gastrointestinal Function
Helsinn Therapeutics (U.S.), Inc
Safety and Efficacy of Ipamorelin for Management of Post-Operative Ileus
Helsinn Therapeutics (U.S.), Inc
Sources: ClinicalTrials.gov, the EU Clinical Trials Information System and ISRCTN, deduplicated so a study registered twice is counted once. A study is counted when Ipamorelin is named as an intervention; studies that only mention it in passing are not.
Questions
Frequently asked
What makes Ipamorelin different from other GH peptides like GHRP-6?
Ipamorelin is uniquely selective—it only releases growth hormone without spiking cortisol, ACTH, or prolactin like other peptides do. Even at doses 200 times higher than needed for GH release, it doesn't affect these other hormones. This makes it the 'cleanest' choice with fewer side effects and hormonal disruptions.
How long does it take to see results from Ipamorelin?
Most people notice improved sleep quality within the first 1-2 weeks. Recovery benefits typically become apparent by weeks 3-4. Body composition changes (fat loss, muscle improvements) usually take 6-12 weeks of consistent use combined with proper diet and exercise. It's a gradual process, not an overnight transformation.
Why do I need to inject multiple times per day?
Ipamorelin has a short half-life of about 2 hours, meaning it clears your system quickly. Multiple injections throughout the day create multiple GH pulses, mimicking how your body naturally releases growth hormone. This pulsatile pattern is more effective and natural than one big dose.
Can I take Ipamorelin with food?
You should NOT take it with food. Eating—especially carbohydrates—causes insulin release, which blunts your GH response. Always inject on an empty stomach (ideally first thing in morning, 2+ hours after meals, or before bed) and wait at least 30 minutes before eating.
Is Ipamorelin the same as HGH?
No, they're quite different. HGH (human growth hormone) is the actual hormone injected directly. Ipamorelin signals your own pituitary gland to release more of YOUR natural GH. This creates a more natural pulsatile release pattern and lets your body maintain its feedback systems. It's gentler and generally has fewer side effects than exogenous HGH.
Should I combine Ipamorelin with CJC-1295?
Many people do, and it's a popular combination. CJC-1295 mimics GHRH (the hormone that tells your pituitary to make GH), while Ipamorelin works through the ghrelin receptor. Together, they amplify each other's effects through two different pathways. You can inject them at the same time for convenience.
Will Ipamorelin make me hungry all the time?
It can increase appetite since it activates the same receptor that makes you feel hungry (the ghrelin receptor). However, this effect is usually mild and some people find it helpful if they're trying to eat more for muscle building. If hunger is problematic, it typically becomes less noticeable after the first few weeks.
Is Ipamorelin legal?
Ipamorelin is not FDA approved and is classified as a research compound. It's legal to purchase for research purposes in many countries, but it's not approved for human medical use. Athletes should note that it's banned by WADA and most sports organizations. Always check your local regulations.
Further reading
History & related research
Ready for the protocol?
Every dosing tier, administration route, timing note, and dose-adjustment rule for Ipamorelin, on one page.