Ipamorelin

Ipamorelin is a synthetic pentapeptide and a selective growth hormone secretagogue, meaning it triggers the body’s own GH release. It does this by tickling the ghrelin receptor (GHS-R1a), the same switch that controls hunger and gut movement, but with a cleaner endocrine profile than older GHRPs Ipamorelin, the first selective growth hormone secretagogue+2.

It was developed in the late 1990s to separate GH stimulation from the cortisol and prolactin bumps that came with GHRP-6 and GHRP-2, and human volunteer studies confirmed it can raise GH without a meaningful cortisol rise even at high multiples of the effective dose Ipamorelin, the first selective growth hormone secretagogue+2.

Most research interest has focused on two directions: supporting the growth hormone axis (often for recovery or body composition) and improving gut motility after surgery Prospective, randomized, controlled, proof-of-concept study of the Ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients+2. A human randomized trial in bowel resection patients tested it for postoperative ileus, and while it did not speed overall recovery, it showed that the peptide can be given repeatedly with acceptable short‑term tolerability Prospective, randomized, controlled, proof-of-concept study of the Ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients.

For the more common wellness uses—lean mass, fat loss, anti‑aging, or injury healing—the evidence is mostly mechanistic, from animal studies, or from community practice patterns rather than controlled human trials Therapeutic Peptides in Aesthetic, Metabolic and Endocrine Conditions: Effects, Safety, Clinical Applications, and Future Perspectives+2.

Ipamorelin is a ghrelin‑receptor (GHS‑R1a) agonist. When it binds to receptors on pituitary somatotroph cells, it triggers the Gq/PLC‑calcium pathway, which makes the pituitary squirt out a pulse of growth hormone. Because it acts like the natural hormone ghrelin but without the heavy orexigenic or stress‑axis baggage, it’s often called the first selective GH secretagogue Ipamorelin, the first selective growth hormone secretagogue+2.

That selectivity is the main reason it’s favored over GHRP‑2 and GHRP‑6: even at doses well above what’s needed for GH release, it doesn’t nudge ACTH or cortisol upward in a meaningful way Ipamorelin, the first selective growth hormone secretagogue+2. Prolactin elevation is also minimal, which reduces the chance of galactorrhea or libido shifts that can happen with less selective secretagogues.

Because ipamorelin binds the ghrelin receptor, it can also influence gut motility and pain signaling through the same pathway. In rodents, it improves gastric dysmotility and dampens visceral pain, but in the human postoperative ileus trial these gut‑specific benefits didn’t translate into faster clinical recovery Prospective, randomized, controlled, proof-of-concept study of the Ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients+3. The peptide is short‑acting; GH peaks after injection (peak timing ~40 min (human PK/PD study, Gobburu et al., 1999)) and washes out quickly, so it’s best thought of as a pulse generator rather than a sustained GH infusion Prospective, randomized, controlled, proof-of-concept study of the Ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients+1.

In practice, this means ipamorelin is typically dosed one to three times a day, often timed away from meals to avoid blunting the GH pulse with insulin or free fatty acids. Bedtime dosing is common because the largest natural GH pulse happens during deep sleep Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers+1.

GH release and endocrine selectivity

The most reliable effect is a dose‑dependent, pulsatile spike in growth hormone with essentially no cortisol or prolactin spillover. Human PK/PD studies and early clinical work have consistently backed this Ipamorelin, the first selective growth hormone secretagogue+2. Because it raises GH, it also tends to increase IGF‑1 over time, which is often used as a proxy marker in community practice.

Bone outcomes (animal data)

Animal bone outcome data are not verified in the provided research corpus. No human bone studies exist, so the human relevance remains speculative.

Postoperative ileus

A human randomized controlled trial gave ipamorelin (0.03 mg/kg IV twice daily) to bowel resection patients. The primary endpoint—accelerated recovery from postoperative ileus—was not met, though the peptide was generally tolerated Prospective, randomized, controlled, proof-of-concept study of the Ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients. Preclinical GI studies are directionally positive, but the clinical effect is unproven for this indication Efficacy of ipamorelin, a ghrelin mimetic, on gastric dysmotility in a rodent model of postoperative ileus+1.

Body composition and recovery

Robust human trial data for muscle gain, fat loss, or athletic recovery are currently lacking. Reviews consistently note that practitioner enthusiasm rests on mechanism, class effects, and animal work, not on controlled physique or performance trials Therapeutic Peptides in Aesthetic, Metabolic and Endocrine Conditions: Effects, Safety, Clinical Applications, and Future Perspectives+2. Many users report better sleep, faster perceived recovery, and a modest lean‑mass effect when combined with training and adequate calories, but these reports come from community protocol, not formal studies.

Fertility (very low confidence)

A small 2026 case series gave ipamorelin 200 mcg SC daily alongside a multimodal protocol to four women with premature ovarian insufficiency and reported pregnancies in all four Restoring endocrine function in women with premature ovarian insufficiency: A case series on hormonal profile reversal and conception following treatment with Ipamorelin. The design is uncontrolled and confounded by many other interventions, so no causal inference can be drawn.

Visceral pain modulation (preclinical)

Ghrelin‑mimetic signaling has been shown to attenuate visceral and somatic nociception in animal models, but this hasn’t been tested in human pain trials <p>Attenuation of Visceral and Somatic Nociception by Ghrelin Mimetics</p>.

Human interventional data come from a postoperative ileus trial (dose not verified in the provided corpus; reportedly 0.03 mg/kg IV twice daily for up to 7 days) and a PK/PD study in volunteers (nmol/kg IV infusions) Prospective, randomized, controlled, proof-of-concept study of the Ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients+1. Those aren’t directly translatable to outpatient SC use, so community‑driven regimens dominate practice.

The most common pattern is 100‑300 mcg subcutaneously one to three times daily, often timed around fasted windows. The logic is straightforward: ipamorelin creates a sharp GH pulse, and that pulse can be blunted if insulin or circulating nutrients are elevated. Pre‑bed dosing is the most popular single dose because it piggybacks on the natural sleep‑entrained GH surge. Morning or post‑workout doses are added if a second or third pulse is desired.

Because the peptide is short‑acting, split‑dosing doesn’t create a constant drip of GH—it produces discrete spikes that mimic physiological pulsatility better than long‑acting agents like MK‑677. That’s also why research protocols typically use it for 8‑12 weeks, followed by 2‑4 weeks off: the idea is to deliver repeated pulse stimulation without chronically flattening the axis.

Body‑weight‑adjusted dosing isn’t well studied. The human PK study used nmol/kg, which converts roughly to 1‑3 mcg/kg, but community protocols almost always use fixed microgram amounts. A 200‑mcg dose is common regardless of body weight, which simplifies titration and keeps syringe volumes easy to manage.

For steeper GH/IGF‑1 responses, ipamorelin is frequently paired with a GHRH analog like CJC‑1295, targeting both the ghrelin and GHRH receptors. The combination adds complexity—and likely amplifies side effects—so monitoring IGF‑1 and glucose becomes even more important Efficacy of ipamorelin, a novel ghrelin mimetic, in a rodent model of postoperative ileus+2.

Ipamorelin is supplied as a lyophilized powder that must be reconstituted before injection. The standard diluent is bacteriostatic water (0.9% benzyl alcohol) for multi‑dose vials; sterile water is acceptable for single‑use or short‑term use only Prospective, randomized, controlled, proof-of-concept study of the Ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients.

Aseptic technique is critical. Wipe the stopper, inject the diluent slowly down the inside wall of the vial, and swirl gently—never shake. Foaming and agitation can degrade the peptide. The reconstituted solution should be clear and particle‑free.

Storage guidance:

• Lyophilized powder: 2‑8°C for routine use, or -20°C for long‑term storage. Protect from light and repeated temperature cycling.
• Reconstituted solution: Keep refrigerated at 2‑8°C. With bacteriostatic water, the typical shelf life is 28‑30 days; with sterile water, ideally use within 7‑14 days due to lack of preservative.
• Never freeze reconstituted peptide; repeated freeze‑thaw cycles accelerate degradation.

Because dosing volumes and concentrations can vary widely depending on vial size and desired dose, an interactive reconstitution calculator on this page handles all the math. It shows you exactly how much diluent to add and what volume to draw for any target dose, so you don’t need to work out mcg/mL ratios by hand.

With other GH secretagogues

The most studied combination is ipamorelin plus a GHRH analog (CJC‑1295, sermorelin, tesamorelin). The two receptors—ghrelin and GHRH—are complementary, and simultaneous activation can generate a larger GH pulse than either alone. The main risk is additive GH/IGF‑1 exposure, which means more potential for edema, glucose shifts, and supraphysiologic IGF‑1 levels Efficacy of ipamorelin, a novel ghrelin mimetic, in a rodent model of postoperative ileus+2. Overlapping GHRPs (e.g., ipamorelin + GHRP‑2) is usually redundant and increases side‑effect risk without clear benefit.

With MK‑677

MK‑677 is an oral, long‑acting ghrelin‑receptor agonist. Adding ipamorelin on top creates sustained + pulsatile agonism, which can drive excessive hunger, water retention, and lethargy. Most practitioners see this as overkill and instead pick one based on whether they want controllable, short pulses (ipamorelin) or round‑the‑clock stimulation (MK‑677) Efficacy of ipamorelin, a novel ghrelin mimetic, in a rodent model of postoperative ileus+2.

With antidiabetic drugs

Ipamorelin can affect glucose handling through GH‑induced insulin resistance; direct pancreatic insulin release has been demonstrated in a preclinical rat model (Adeghate et al., 2004), but human relevance remains uncertain. In someone already on insulin, sulfonylureas, or GLP‑1 agonists, fasting glucose should be checked within the first 1‑2 weeks and periodically thereafter. The net effect is often a small upward drift in fasting glucose, but individual responses vary.

With BPC‑157 / TB‑500 recovery peptides

These “healing peptides” work through different pathways (angiogenesis, nitric oxide, fibroblast migration) and are commonly stacked with ipamorelin in recovery protocols. No direct antagonism is known, but the evidence for the stack’s synergy is almost entirely anecdotal Pharmacokinetic evaluation of ipamorelin and other peptidyl growth hormone secretagogues with emphasis on nasal absorption+1.

With fertility and sex‑hormone therapies

A case series combined ipamorelin with a broad functional‑medicine protocol and reported pregnancies Restoring endocrine function in women with premature ovarian insufficiency: A case series on hormonal profile reversal and conception following treatment with Ipamorelin, but the design makes it impossible to know whether ipamorelin contributed. When used alongside clomiphene, hCG, or exogenous testosterone, lab values (IGF‑1, prolactin, LH/FSH) should be interpreted with extra caution because the axis is being pulled from multiple directions.

Addiction and anti‑doping

Ipamorelin has established urinary and blood‑spot detection methods and is prohibited in sport under WADA’s S2 class. Any co‑use with other banned peptides increases the metabolic footprint and detection window Pharmacokinetic evaluation of ipamorelin and other peptidyl growth hormone secretagogues with emphasis on nasal absorption+2.

There are no randomized human trials comparing a continuous ipamorelin regimen against a cycled one. The practice of cycling (e.g., 8‑12 weeks on, 2‑4 weeks off) comes from practitioner consensus and the general pharmacologic behavior of GH secretagogues Ipamorelin, the first selective growth hormone secretagogue+2.

Reasons to cycle include:

• Diminishing subjective response: Many users report that sleep, recovery, and appetite effects fade after 8‑12 weeks of continuous use, even when biological activity persists.
• Avoiding chronic GH/IGF‑1 elevation: Continuously pushing the axis without breaks could theoretically downregulate pituitary sensitivity or overwhelm feedback loops, though this hasn’t been proven with ipamorelin.
• Managing appetite and weight drift: Because it tickles the ghrelin receptor, hunger can creep up over time in some individuals, which works against fat‑loss goals.
• Lack of long‑term safety data: The longest controlled exposure in humans is 7 days (postoperative IV), so extending cycles to many months carries unknown risk Prospective, randomized, controlled, proof-of-concept study of the Ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients.

Common cycling templates:

• 8‑12 weeks on / 2‑4 weeks off (most common)
• 5 days on / 2 days off each week within an 8‑12 week block
• 12‑16 weeks on only when combined with a GHRH analog, then 4 weeks off

Signs that a break may be helpful: fading benefits, progressive edema or glucose rise, boredom with the routine, or no measurable change after 3‑4 weeks at a standard dose. There’s no rebound cortisol surge expected with ipamorelin because of its selectivity, but IGF‑1 should drift back toward baseline within a few weeks of stopping Ipamorelin, the first selective growth hormone secretagogue+1.

The most popular stack is ipamorelin + CJC‑1295 (no DAC). The rationale is dual‑pathway stimulation: ipamorelin opens the ghrelin‑receptor gate, while CJC‑1295 keeps the GHRH‑receptor gate open. Together they can produce a robust, yet still pulsatile, GH surge that’s larger than either alone. Doses in community protocols typically match—100‑300 mcg of each, injected once or twice daily—and IGF‑1 monitoring at week 4‑6 is standard to avoid overshooting Efficacy of ipamorelin, a novel ghrelin mimetic, in a rodent model of postoperative ileus+2.

For injury recovery, many stack ipamorelin with BPC‑157 and/or TB‑500. These peptides target soft‑tissue repair through angiogenesis and fibroblast migration, which is mechanistically distinct from the GH‑axis. No formal trials exist, but the combination is common in sports‑medicine settings and generally well tolerated Pharmacokinetic evaluation of ipamorelin and other peptidyl growth hormone secretagogues with emphasis on nasal absorption+1.

Stacks to approach with caution:

• Ipamorelin + MK‑677: Redundant ghrelin‑receptor overstimulation, high hunger, fluid retention.
• Ipamorelin + exogenous GH or IGF‑1 LR3: Overshooting IGF‑1 and glucose dysregulation become real concerns; lab work is non‑negotiable.
• Ipamorelin + GLP‑1 agonists: Appetite effects oppose each other, but the GH increase can still alter glucose handling, so the net metabolic effect is hard to predict Efficacy of ipamorelin, a novel ghrelin mimetic, in a rodent model of postoperative ileus+2.

When stacking, the single most practical safety move is to check fasting glucose and IGF‑1 at baseline and again after 4‑6 weeks. If IGF‑1 climbs above the age‑adjusted normal range, the most common step is to reduce the GHRH analog dose first, then the ipamorelin dose if needed.

United States

Ipamorelin is not FDA approved for any indication and remains an investigational peptide. Reviews consistently classify it alongside other unapproved GH secretagogues Ipamorelin, the first selective growth hormone secretagogue+2. That means it cannot be legally marketed or sold as a dietary supplement, and any compounded or gray‑market product operates outside FDA‑approved pathways.

Human clinical data do exist—most notably a randomized controlled trial in postoperative ileus—but clinical study does not equal regulatory approval. The compound sometimes appears through physician‑directed compounding arrangements or online importation, which introduces significant quality and purity risks Prospective, randomized, controlled, proof-of-concept study of the Ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients+1.

International

No major regulator (EMA, MHRA, TGA) has approved ipamorelin. The literature treats it as an investigational peptide globally. Customs restrictions vary by country, but importing an unapproved injectable peptide carries legal risk nearly everywhere Ipamorelin, the first selective growth hormone secretagogue+2.

Sports & anti‑doping

Ipamorelin is prohibited under the World Anti‑Doping Code, S2 class (peptide hormones, growth factors, related substances, and mimetics). The prohibition applies both in‑competition and out‑of‑competition. Analytical methods can detect ipamorelin and its metabolites (like Ipamorelin (1‑4) free acid) in urine and dried blood spots, so the detection window extends beyond the parent compound’s short half‑life Pharmacokinetic evaluation of ipamorelin and other peptidyl growth hormone secretagogues with emphasis on nasal absorption+2. Strict‑liability rules mean any adverse analytical finding leads to sanctions regardless of intent.

For athletes, the practical message is clear: ipamorelin is a banned substance, and contamination risk from gray‑market products is another layer of liability Prospective, randomized, controlled, proof-of-concept study of the Ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients+1.

Ipamorelin’s safety advantage stems from its endocrine selectivity. Human pharmacology and reviews consistently note that, unlike GHRP‑2 and GHRP‑6, it doesn’t significantly raise ACTH, cortisol, or prolactin—even at high doses Ipamorelin, the first selective growth hormone secretagogue+2. That reduces risk of cortisol‑driven agitation, insulin resistance, or galactorrhea.

Most common side effects

Reported effects are mild and typical of GH secretagogues: transient flushing, headache, lightheadedness, increased appetite, and injection‑site irritation. In the 7‑day postoperative ileus trial, treatment‑emergent adverse events were common in both arms, but the peptide itself was generally well tolerated Prospective, randomized, controlled, proof-of-concept study of the Ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients. Water retention, mild edema, and carpal‑tunnel‑like paresthesias can occur, especially when stacked with CJC‑1295 or when IGF‑1 levels climb above the age‑adjusted reference range Efficacy of ipamorelin, a novel ghrelin mimetic, in a rodent model of postoperative ileus+1.

Metabolic concerns

Because GH‑axis activation can worsen insulin sensitivity, fasting glucose should be checked at baseline and periodically. Ipamorelin's effect on glucose handling is primarily through GH‑mediated insulin resistance; direct insulin release has been demonstrated in a preclinical rat model (Adeghate et al., 2004), but human relevance remains uncertain. In practice, a modest upward drift in fasting glucose is the most common metabolic signal, and it usually reverses upon discontinuation.

Theoretical risks

• Cancer: No direct carcinogenicity data exist, but any intervention that raises GH/IGF‑1 carries a theoretical concern for IGF‑1‑responsive tumors. Avoid in active malignancy or recent cancer treatment Efficacy of ipamorelin, a novel ghrelin mimetic, in a rodent model of postoperative ileus+2.
• Pituitary overstimulation: Prolonged supraphysiologic IGF‑1 could, in theory, accelerate GH‑sensitive pathology like acromegaly or diabetic retinopathy. Monitoring IGF‑1 and staying within age‑adjusted norms is the conservative approach.
• Product quality: Unapproved peptide markets have documented contamination, mislabeling, and impurity problems. Adverse events can therefore come from the product rather than the molecule itself Pharmacokinetic evaluation of ipamorelin and other peptidyl growth hormone secretagogues with emphasis on nasal absorption.

Who should not use it

Absolute contraindications include active cancer, pregnancy (controlled data are absent), and known hypersensitivity. Relative contraindications include diabetes, uncontrolled hypertension, sleep apnea, and prior pituitary adenoma. Elderly users and those on multiple glucose‑active drugs should start with the lowest dose and monitor closely Efficacy of ipamorelin, a novel ghrelin mimetic, in a rodent model of postoperative ileus+1.

Monitoring essentials

At a minimum: IGF‑1 and fasting glucose at baseline, again at week 4‑6, and at the end of any cycle longer than 8 weeks. Track morning weight, waist circumference, blood pressure, and edema weekly. If IGF‑1 exceeds the age‑adjusted upper limit or glucose worsens, reduce the dose or pause treatment Ipamorelin, the first selective growth hormone secretagogue+3.