Ipamorelin is a synthetic pentapeptide (five amino acids: Aib-His-D-2-Nal-D-Phe-Lys-NH2) that acts as a selective agonist at the growth hormone secretagogue receptor (GHS-R1a). It stimulates the pituitary gland to release growth hormone in a pulsatile pattern that closely mirrors natural secretion. It was first described in a 1998 peer-reviewed paper and characterized as the first selective growth hormone secretagogue because it stimulates GH without meaningfully raising cortisol or prolactin at typical doses.

Is ipamorelin FDA-approved?

No. Ipamorelin is not approved by the FDA or any other major regulatory agency for human use in any indication. It is classified as an investigational compound and is subject to compounding restrictions in the United States. It is also listed as a banned substance under the World Anti-Doping Agency (WADA) prohibited list (S2, Peptide Hormones, Growth Factors, Related Substances, and Mimetics).

How is ipamorelin different from other growth hormone secretagogues?

Most older GHRPs (like GHRP-2 and GHRP-6) raise cortisol and prolactin alongside GH, which is considered a drawback by researchers. The original characterization of ipamorelin in 1998 noted that it did not significantly raise either hormone in animal studies at doses that produced strong GH release, making it more selective. It does not appear to stimulate appetite to the same degree as GHRP-6, which binds more broadly to ghrelin receptors in the gut.

What are the reported dosing ranges for ipamorelin?

Research protocols and clinical wellness settings most commonly report doses of 100-300 mcg administered by subcutaneous injection, one to three times per day, often timed around sleep or fasting windows to align with the body's natural GH pulse timing. Cycle lengths of 8-12 weeks followed by a break are sometimes described, though no standardized protocol has been validated in large clinical trials. These are reported ranges, not prescriptive instructions.

What side effects have been reported with ipamorelin?

At doses studied in early research, ipamorelin has generally been reported as well tolerated, with injection site reactions (redness, mild discomfort) being the most commonly noted side effect. Some users report transient water retention, especially early in a protocol, as elevated GH can affect fluid balance. Headaches and a mild flushing sensation have also been mentioned in informal reports. Long-term human safety data is limited, and rare or serious effects cannot be excluded without larger trials.

Ipamorelin · Redose

Creator: Redose
Published: 2026-05-05

Ipamorelin is a synthetic pentapeptide that selectively activates the growth hormone secretagogue receptor (GHS-R1a) in the pituitary gland, triggering a pulsatile release of endogenous growth hormone. First described in a 1998 paper that characterized it as "the first selective growth hormone secretagogue," it has attracted ongoing research interest for its relatively clean receptor profile compared to older peptides in the same class. It is an investigational compound with no current regulatory approval for human use.

What is ipamorelin

Ipamorelin is a five-amino-acid peptide (pentapeptide) with the sequence Aib-His-D-2-Nal-D-Phe-Lys-NH2. It was developed as a member of the growth hormone releasing peptide (GHRP) family, a class of synthetic compounds that mimic the action of ghrelin at the GHS-R1a receptor to stimulate growth hormone secretion from the anterior pituitary.

What distinguished ipamorelin from earlier peptides in its class was its selectivity. Preclinical studies showed that it produced robust GH release without the corresponding elevations in cortisol and prolactin that were commonly observed with GHRP-2 and GHRP-6. This selectivity profile has made it a compound of continued interest in both academic research and clinical wellness contexts, although human clinical trial data remains limited.

Ipamorelin has an approximate plasma half-life of 2 hours following subcutaneous injection, which is meaningfully longer than older GHRPs (many of which clear in under an hour) and contributes to its sustained GH-releasing effect within each injection window.

How it works

Ipamorelin works by binding to and activating GHS-R1a, the primary receptor for the endogenous hunger hormone ghrelin. When ipamorelin occupies this receptor on pituitary somatotroph cells, it triggers a calcium-mediated signaling cascade that leads to GH secretion. Several features of this mechanism are worth noting:

Pulsatile secretion: Ipamorelin stimulates GH in a discrete pulse rather than causing a continuous elevation, which more closely resembles the body's natural secretory pattern driven by hypothalamic growth hormone-releasing hormone (GHRH).
Selectivity for the pituitary GHS-R1a: Unlike GHRP-6, ipamorelin has relatively low affinity for ghrelin receptors in the gastrointestinal tract, which is one reason it does not appear to strongly stimulate appetite.
Synergy with GHRH analogs: Ipamorelin is frequently studied and used alongside GHRH peptides (such as CJC-1295 or sermorelin) because the two pathways act on complementary steps in the GH release process. The combination is reported to produce a larger and more consistent GH pulse than either compound alone.
Insulin-like growth factor 1 (IGF-1) downstream: GH released in response to ipamorelin signals the liver to produce IGF-1, which mediates many of the downstream effects on muscle, fat, and connective tissue that are attributed to the GH axis broadly.

What the research says

Most ipamorelin research has been conducted in animal models. The foundational 1998 paper demonstrated potent and selective GH release in rats with a favorable safety profile at the studied doses. Subsequent preclinical work has explored its potential in areas including:

Area	Preclinical findings
Body composition	Increased lean mass, reduced fat mass in GH-deficient animal models
Bone density	Some evidence of increased bone mineral content in rodent studies
Recovery and repair	Preliminary data on wound healing and tissue remodeling, often in combination with other compounds
Motility	Ipamorelin and related GHRPs have been studied for gastrointestinal motility, with some animal data suggesting potential in postoperative ileus

Human data is sparse. There are no large, peer-reviewed randomized controlled trials evaluating ipamorelin for any indication in humans. Small clinical observations and case series exist within the compounding pharmacy and men's health clinic literature, but these carry significant methodological limitations. Researchers and clinicians working in this space consistently note the need for formal human trials before efficacy or long-term safety can be confirmed.

Typical dosing

Dosing information for ipamorelin comes from animal research, early-phase pharmacokinetic observations, and protocols described in compounding pharmacy and clinical wellness contexts. No standardized human dosing has been established.

Reported protocols commonly describe:

Dose per injection: 100-300 mcg subcutaneously
Frequency: 1-3 injections per day, sometimes timed to maximize the natural GH pulse (e.g., before sleep or in a fasted state before training)
Cycle length: 8-12 weeks followed by a break, though practices vary
Combination protocols: Frequently paired with a GHRH peptide to amplify the GH pulse

Reconstituting ipamorelin powder correctly and calculating the right injection volume are essential steps before use. The reconstitution guide at /guides/how-to-reconstitute-peptides covers the process in detail, and the free peptide calculators at /calculators handle the unit conversion math.

A note on timing and injection sites: Because ipamorelin is typically injected multiple times per day, rotating injection sites is important to avoid localized tissue damage. The injection site rotation guide at /guides/injection-site-rotation explains how to manage a multi-site rotation safely.

Side effects and safety

In preclinical research at typical dose ranges, ipamorelin has been reported as well tolerated. The selectivity that distinguishes it from older GHRPs means it does not appear to produce meaningful elevations in cortisol or prolactin at studied doses, which is considered advantageous from a safety perspective.

Reported side effects in human use contexts include:

Injection site reactions: Redness, mild swelling, or discomfort at the injection site are the most commonly mentioned adverse effects.
Water retention: Elevated GH can transiently increase fluid retention, which some users notice as mild puffiness, particularly early in a protocol.
Headaches: Reported in some informal accounts, possibly related to fluid shifts or transient changes in intracranial pressure.
Mild flushing: A brief sensation of warmth following injection has been noted by some users.

The absence of large-scale human trials means that rare or serious adverse effects cannot be characterized. Ipamorelin affects a central endocrine axis (the GH-IGF-1 axis), and long-term consequences of repeated stimulation in adults are not well understood. Any use in a clinical setting should involve monitoring of IGF-1 levels and other relevant biomarkers.

Tracking ipamorelin with Redose

Ipamorelin protocols typically involve multiple daily injections over multi-week cycles, which makes consistent tracking particularly important. Redose is designed for exactly this use case: log each injection with one tap, let the app track your vial inventory and alert you when it is time to reorder, rotate injection sites automatically with the built-in body map, and set reminders timed to your specific injection windows (pre-sleep, pre-training, morning fasted).

Download Redose at /#download and use the free peptide calculators at /calculators to set up your reconstitution math before your first injection.

This profile is educational information, not medical advice. Talk to a qualified healthcare provider before starting any protocol.

Ipamorelin