Ipamorelin 10mg

The most striking feature of ipamorelin is not what it releases — it's what it doesn't. Unlike earlier growth hormone secretagogues that flood the endocrine system with cortisol and prolactin alongside GH, this pentapeptide triggers growth hormone pulses with minimal collateral activation. That selectivity, demonstrated consistently in rodent models and small human pharmacokinetic studies, makes it a useful reference compound for understanding GHS-R1a signaling — even if long-term human safety data remain absent.

A Synthetic Pentapeptide Built for Selective GH Release

Ipamorelin is a five-amino-acid peptide with the sequence Aib-His-D-2-Nal-D-Phe-Lys-NH2 and a molecular weight of 711.85 Da. Researchers designed it in the late 1990s as part of a broader effort to develop growth hormone secretagogues that would avoid the unwanted hormonal side effects seen with earlier compounds like GHRP-6 and GHRP-2. The inclusion of unnatural amino acids — particularly the D-isomers and alpha-aminoisobutyric acid (Aib) — protects it from rapid enzymatic degradation while preserving receptor selectivity.

It belongs to the growth hormone secretagogue class, meaning it stimulates endogenous GH production rather than supplying exogenous hormone. This positions it alongside compounds like Hexarelin and Sermorelin, though its pharmacological profile diverges in ways that matter for experimental design. For research purposes only, it serves primarily as a tool for investigating GHS-R1a-mediated signaling and downstream effects on body composition, bone density, and metabolic parameters.

GHS-R1a Agonism Without the Cortisol Spike

Ipamorelin binds the growth hormone secretagogue receptor 1a (GHS-R1a), a G-protein-coupled receptor expressed in somatotroph cells of the anterior pituitary, neurons in the hypothalamic arcuate nucleus, and peripheral tissues including adipose, heart, and skeletal muscle. GHS-R1a is the endogenous receptor for ghrelin, but ipamorelin acts independently of ghrelin and does not require ghrelin to be present.

Receptor activation triggers Gq signaling, which raises intracellular calcium and activates protein kinase C. This cascade stimulates the release of growth hormone from pituitary stores. Circulating GH then binds hepatic GH receptors, inducing production of insulin-like growth factor 1 (IGF-1), which mediates many of growth hormone's anabolic effects. In rodent anterior pituitary cell cultures, ipamorelin increased GH secretion in a dose-dependent manner, with an EC50 in the low nanomolar range — comparable to ghrelin itself.

What sets ipamorelin apart is its limited off-target activity. In Sprague-Dawley rats, intravenous ipamorelin at doses up to 500 µg/kg raised GH levels sharply but did not significantly elevate cortisol, prolactin, or adrenocorticotropic hormone (ACTH) compared to saline controls. By contrast, GHRP-2 and GHRP-6 at equipotent GH-releasing doses caused measurable cortisol and prolactin surges. This selectivity appears to stem from ipamorelin's lower affinity for receptors outside the GH axis, though the exact binding profile across other GPCR subtypes has not been exhaustively mapped.

Growth Hormone Pulses in Rodents, Sparse Data in Humans

Most published ipamorelin research focuses on short-term pharmacodynamics in rodent models. In male rats, subcutaneous ipamorelin (0.1–1 mg/kg) produced peak plasma GH elevations within 20–40 minutes, with levels returning to baseline by 2–3 hours. The GH release followed a classic pulsatile pattern, mimicking endogenous secretion. Chronic administration (21 days) in aged rats showed sustained GH responsiveness without evident tachyphylaxis, suggesting the receptor does not rapidly desensitize under repeated agonist exposure.

In one pharmacokinetic study involving healthy adult human volunteers, a single subcutaneous dose of ipamorelin (0.1–1 µg/kg) elevated serum GH in a dose-dependent manner, with peak levels occurring around 30 minutes post-injection. IGF-1 concentrations rose modestly over the following 24 hours. Cortisol and prolactin remained within normal ranges across all doses tested. These findings align with the rodent data, but the study lacked long-term follow-up or systematic safety monitoring.

No peer-reviewed Phase II or Phase III trials in humans have been published as of 2026. Industry-sponsored work suggested potential applications in growth hormone deficiency and age-related sarcopenia, but none advanced to regulatory approval. Case reports and anecdotal accounts from research communities describe use at doses ranging from 200 to 300 µg per injection, typically administered once or twice daily, though these protocols lack controlled validation.

Animal studies on body composition showed mixed results. In a 28-day study on growing rats, ipamorelin increased lean body mass and reduced fat mass compared to saline-treated controls, with effects roughly proportional to the magnitude of GH elevation. Bone mineral density increased in ovariectomized rats treated with ipamorelin for 12 weeks, suggesting a protective role in osteopenia models. However, these outcomes reflect specific rodent physiology and cannot be extrapolated to human tissue without controlled trials.

Subcutaneous Dosing, Brief Half-Life, and Stability Constraints

In rodent pharmacokinetic studies, ipamorelin showed a plasma half-life of approximately 2 hours following intravenous administration. Subcutaneous injection extended the duration of detectable GH elevation, likely due to slower absorption from the injection site, but the peptide itself cleared rapidly. This short half-life necessitates multiple daily doses to maintain elevated GH if sustained secretion is the research objective.

Published rodent protocols used doses ranging from 0.1 to 1 mg/kg body weight, administered subcutaneously or intraperitoneally. Human pharmacokinetic studies tested 0.1 to 1 µg/kg, which translates to roughly 7 to 70 µg for a 70 kg individual. However, these doses were single-bolus injections aimed at measuring acute GH response, not establishing chronic efficacy or safety thresholds.

Ipamorelin is supplied as a lyophilized powder and reconstituted in bacteriostatic water or saline. Once reconstituted, it remains stable for up to 14 days when refrigerated at 2–8°C. Freezing reconstituted peptide can cause aggregation and loss of activity. Dry powder should be stored at -20°C or colder to preserve potency over months.

Concurrent use with CJC-1295 DAC or Mod GRF 1-29 — both growth hormone-releasing hormone (GHRH) analogs — is common in research contexts. The rationale is synergistic: GHRH analogs prime somatotrophs for GH release, while ghrelin receptor agonists like ipamorelin trigger the actual secretory event. In rat pituitary cultures, combined treatment produced greater GH output than either agent alone. Whether this translates to enhanced physiological outcomes in long-term models has not been rigorously tested.

FAQ

Q: How does ipamorelin differ from other growth hormone secretagogues like GHRP-6 or Hexarelin?

Ipamorelin's defining feature is selectivity. In rodent models, it raises GH without significantly increasing cortisol, prolactin, or ACTH — hormones that rise sharply with GHRP-6 and Hexarelin at equipotent doses. This makes it cleaner for isolating GH-specific effects in experimental protocols, though it also means the compound may lack some of the broader endocrine activity that earlier secretagogues display.

Q: What is the typical dose range for ipamorelin in published research?

Rodent studies used 0.1 to 1 mg/kg subcutaneously. In the single published human pharmacokinetic trial, doses ranged from 0.1 to 1 µg/kg (roughly 7 to 70 µg for a 70 kg adult). Unpublished protocols and case reports suggest 200 to 300 µg per injection in research settings, but these lack systematic validation or safety monitoring.

Q: Does ipamorelin cause desensitization with repeated use?

A 21-day rat study found sustained GH responsiveness to daily ipamorelin without evident tachyphylaxis, suggesting the GHS-R1a receptor does not rapidly desensitize under chronic agonist exposure. However, this was a single rodent study; whether the same holds in humans over months or years is unknown. Long-term receptor dynamics have not been characterized.

Q: Can ipamorelin be used with CJC-1295 or other GHRH analogs?

Yes, and this combination is common in research contexts. GHRH analogs like CJC-1295 or Mod GRF 1-29 work through a different receptor (the GHRH receptor) and prime somatotrophs for GH release, while ipamorelin triggers the secretory pulse via GHS-R1a. In rat pituitary cultures, the two pathways showed synergistic effects on GH output, though long-term physiological outcomes from this combination remain understudied.

Q: What are the known risks or side effects in humans?

Controlled human safety data are sparse. The single published pharmacokinetic study reported no serious adverse events at doses up to 1 µg/kg, though follow-up was short. Anecdotal reports describe mild transient flushing, headache, and injection site reactions. Long-term endocrine effects, cancer risk, and interactions with chronic disease states have not been systematically evaluated.

Ipamorelin is intended for laboratory and investigational use only. It is not approved by the FDA or any regulatory body for medical treatment. Statements regarding its effects are based on preclinical research and limited human pharmacokinetic data; they have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease.