Ipamorelin

Ipamorelin is a small, lab-made peptide consisting of five amino acids. It is intended to trigger a gentle growth hormone boost in the body, which is why it is used off-label (i.e., outside officially approved applications) for anti-aging and regeneration. Technically, it acts as an agonist (a substance that selectively activates a receptor) at the ghrelin receptor (GHS-R1a), the docking site for the body's own 'hunger hormone' ghrelin, located in the pituitary gland (brain

Also seen on labels, in price lists and in the community as: IPA

Editorial team ·Updated Aug 25, 2026 ·4 Sources ·evidence-rated ·independent & ad-free

Common use common practice, unverified

How this peptide is typically used - described, not recommended.

How much

100-300 µg per dose

How often

1-3 times a day

How long

8-12 weeks straight, then a 4-8-week break

Administration

Injection

Ipamorelin is given as a subcutaneous injection (under the skin). The reported dose is 100 to 300 micrograms per injection, usually one to three times a day. People take it on an empty stomach before bedtime. Reported cycles last 8 to 12 weeks, followed by a 4 to 8 week break to keep the receptors sensitive. These protocols come from forums and unapproved clinic recommendations, not from controlled studies. Their effect on individuals has not been scientifically verified.

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As of Aug 21, 2026

Ipamorelin is a laboratory-made signaling peptide composed of five amino acids. It was developed to stimulate the body's own growth hormone release more specifically than older substances. Today, it is mainly discussed in the off-label context, i.e., outside officially approved indications, for anti-aging and regeneration.

Ipamorelin belongs to the class of growth hormone secretagogues (GHRPs). These are peptides that cause the body to release its own growth hormone (GH). Ipamorelin acts as a selective agonist at the ghrelin receptor (GHS-R1a), meaning it specifically activates this receptor. This docking site is normally activated by the body's own 'hunger hormone' ghrelin and is located in the pituitary gland. There, ipamorelin stimulates the body's own pulsatile (rhythmic, intermittent) release of growth hormone (GH). The pharmacological selectivity is high: even at doses well above the ED50 for GH (the dose at which half-maximal effect occurs), ACTH and cortisol (stress hormones) as well as prolactin (lactation/sexual hormone) are not clinically significantly elevated.

This selectivity distinguishes ipamorelin from older GHRPs such as GHRP-6 or GHRP-2. It is considered the first 'clean' GHRP receptor agonist. It was developed in the late 1990s by Novo Nordisk under the code NNC 26-0161.

How does ipamorelin work?

Ipamorelin binds to the ghrelin receptor (GHS-R1a) on somatotropic cells (the GH-producing cells) of the anterior pituitary gland (the front part of the pituitary gland, roughly behind the root of the nose). There, it triggers a short, concentration-dependent release of growth hormone. Via the GH axis, IGF-1 (insulin-like growth factor 1, the most important signaling molecule produced in the liver under the influence of growth hormone) secondarily increases in the liver.

What happens in the body?

Pulsatile GH release: A single GH pulse, peak approx. 30-40 minutes after subcutaneous administration, return to baseline within 2-3 hours.
Indirect IGF-1 increase: Via the physiological GH cascade, measurable in a dose-dependent manner in studies.
No significant cortisol or ACTH increase: In contrast to GHRP-6 and GHRP-2 - a decisive pharmacological advantage.
No significant prolactin, FSH, LH, or TSH shift: Prolactin is a lactation/sexual hormone, FSH and LH control fertility and sexual function, TSH regulates the thyroid. Selectivity clinically confirmed (Raun et al., Eur J Endocrinol 1998).
Weak appetite effect: Significantly less than with GHRP-6, despite activation of the same receptor (only partial activation of the signaling pathways responsible for appetite).

What is the state of the evidence?

The pharmacological and pharmacokinetic data (i.e., data on absorption, distribution, metabolism, and potency in the body) on ipamorelin in humans are solid. However, clinical development for approval has failed:

1998 - First description: Raun et al. characterized ipamorelin in the European Journal of Endocrinology as the first selective GH secretagogue - GH potency and efficacy comparable to GHRP-6, but without the unwanted ACTH and cortisol elevations (PMID 9849822).
1999 - PK/PD in humans: Gobburu et al. modeled pharmacokinetics and pharmacodynamics (absorption, distribution, and metabolism in the body and how strongly the effect arrives there) in healthy subjects: dose-proportional kinetics, terminal half-life approx. 2 hours, GH peak at 0.67 hours (PMID 10496658).
2014 - Phase II postoperative ileus: Beck et al. (Beck DE, Sweeney WB, McCarter MD; Ipamorelin 201 Study Group, published in Int J Colorectal Dis 2014;29(12):1527-34) investigated ipamorelin in a phase II study (a smaller phase 2 clinical study before the large phase 3 registration study) to accelerate gastrointestinal recovery after colorectal surgery (colon surgery) with postoperative ileus (a temporary paralysis of the bowel in which the intestine does not transport the food pulp). A numerical improvement in time to first tolerated meal was shown (25.3 vs. 32.6 h), but the primary endpoint (the predefined main effect for which the study was designed) was not reached; the program was subsequently discontinued.
Regulatory status: Neither FDA nor EMA approval. From September 2023 to September 2024, ipamorelin was on the FDA 503A compounding list (a list for individually compounded medications in pharmacies), category 2, but was removed after the applicant withdrew. WADA-prohibited (S2 Growth Hormone Secretagogues).

What is missing?

No phase III data, no approved indication.
No published human studies on anti-aging, body composition, or regeneration endpoints beyond GH/IGF-1 biomarkers (measurable laboratory values that only show that the axis is active, but not a real clinical benefit).
Long-term safety in the off-label setting (years) is not systematically documented.

What is ipamorelin used for in practice?

Despite the lack of approval, ipamorelin has become established in the off-label area - mainly in two contexts:

Anti-aging and recovery: Deeper sleep, faster recovery, better collagen and skin quality, slight fat reduction - effects that can be explained by the physiological GH pulsatility. Often combined with CJC-1295 (a GHRH analog, i.e., a relative of growth hormone-releasing hormone, which stimulates the pituitary itself to release GH) for synergistic GH release (Veldhuis & Bowers 2009).
Regeneration and sport: Support of muscle and connective tissue repair via GH/IGF-1 signaling pathways - comparable to Tesamorelin, which, however, is GHRH-based and FDA-approved.

What you should pay attention to

Half-life approx. 2 hours: Half-life means the time in which half of the substance is broken down in the body. Therefore, typically multiple times daily or combined with long-acting GHRH analogs (e.g., CJC-1295 DAC, a variant with prolonged duration of action, half-life approx. 6-8 days).
Appetite: Significantly less than with GHRP-6, but individual differences are possible.
Injection timing: Often in the evening or before sleep to mimic the natural nocturnal GH peak.
Storage: Store the lyophilized vial (freeze-dried vial in powder form) cool and dry. After reconstitution with bacteriostatic water (sterile water with a small preservative additive), keep in the refrigerator (2-8 °C) and use within a few days (exact shelf life depends on the manufacturer).
No reimbursement by health insurance and no medical prescription for 'anti-aging' - the use is exclusively outside approved indications.

Frequently asked questions

Is ipamorelin the same as HGH?

No. Ipamorelin is a signaling peptide that stimulates the pituitary to release its own GH - it does not itself contain growth hormone. This preserves physiological pulsatility, unlike exogenous HGH (growth hormone artificially supplied from outside), which can reduce the body's own production.

What is the difference from GHRP-6?

GHRP-6 is an older, less selective GHS-R1a agonist with significant co-stimulation of ACTH, cortisol, and prolactin as well as a pronounced hunger effect. Ipamorelin is significantly 'cleaner' on these axes.

How does ipamorelin fit into the Peptigraph library?

Because ipamorelin is neither FDA- nor EMA-approved and clinical development ended in 2014, I list it as a separate entry with selectivity and study data. You can find the direct comparison in the CJC-1295/Ipamorelin blend entry, and the approved GHRH relative at Tesamorelin.

Peptigraph serves information and education. I do not provide medical advice, dosage instructions, or purchasing recommendations. Talk to a doctor you trust before using any peptide.

Evidence at a glance

Research status

Ipamorelin is a synthetic pentapeptide growth hormone secretagogue (GHS) that is not FDA-approved for any indication [3, 5, 6, 17]. Preclinical data show it stimulates growth hormone (GH) release without significantly raising cortisol, ACTH, or prolactin [3, 5]. In vitro, it releases GH from primary rat pituitary cells [1, 21]. Animal models include swine models for hormonal selectivity [3], male rats for pharmacokinetics [8], adult rat models for bone and muscle effects [13, 16], a rodent model for postoperative ileus [18], and young female rats for chronic administration effects [11]. Human evidence is limited to a pharmacokinetic/pharmacodynamic (PK/PD) study in healthy volunteers [2, 5, 23] and Phase 2 trials for postoperative ileus [4, 7, 10]. There are no Phase 3 trials.

Human evidence

Human clinical data for ipamorelin are limited. A randomized, placebo-controlled, dose-escalation study characterized the PK and PD of ipamorelin in 48 healthy male volunteers [2, 5, 23]. This study modeled GH release but explicitly did not report effectiveness data for the diagnosis or treatment of growth hormone deficiency (GHD) [5]. Helsinn Therapeutics sponsored Phase 2, randomized, proof-of-concept studies to evaluate the safety and efficacy of ipamorelin for the management of postoperative ileus following abdominal surgery (ClinicalTrials.gov NCT00672074 and NCT01280344) [4, 7, 10]. Published results from NCT00672074 indicated ipamorelin showed some efficacy signals in postoperative ileus management, but development did not lead to approval [7, 10].

Dosages in studies & practice

No FDA-approved dosing exists. The following dosages are reported descriptively from cited sources and are not recommendations. Human PK/PD study (healthy volunteers): 5 different intravenous infusion rates: 4.21, 14.02, 42.13, 84.26, and 168.52 µg/h [23]. Rat study (bone formation): 100 µg/kg three times daily, subcutaneous, for 3 months [13]. Rat study (glucocorticoid interaction): Acute response to ipamorelin after methylprednisolone 5.0 mg/kg for 8 days [16]. In vitro (rat pituitary cells): EC₅₀ = 1.3 ± 0.4 nmol/L [1]. Rodent postoperative ileus model: 1 µM (in vitro concentration) [18].

Risks & side effects

The FDA has flagged compounded ipamorelin acetate for safety risks, placing it in "Category 2" under the 503B compounding interim policy, meaning it may present significant safety risks [6]. Compounded drugs containing ipamorelin acetate may pose a risk for immunogenicity due to potential aggregation or peptide-related impurities, and the presence of unnatural amino acids adds to the complexity of peptide characterization [5, 6]. The FDA notes that a published study identified serious adverse events, including death, when ipamorelin was administered intravenously for improving gastric motility [6]. For other injectable routes, the FDA "lacks sufficient information to know whether the drug would cause harm if administered to humans" [6].

Research gaps

There is no FDA-approved use for ipamorelin [3, 17]. Human studies are few and primarily focused on PK/PD or postoperative ileus, not on growth hormone deficiency, anti-aging, or anabolic uses [5, 7]. There are no registrational Phase 3 trials in any indication. The FDA states it lacks sufficient information to know whether the drug would cause harm via injectable routes other than IV [6]. All identified human exposure data are acute (PK/PD) or short-term perioperative; no chronic human safety studies were identified in the provided sources.

Editorial, sourced from primary literature - not medical advice.