Ipamorelin
Ipamorelin Acetate
Regulatory Status
Not FDA-approved. Available via compounding pharmacies. Often paired with CJC-1295.
FDA · Updated Mar 2026
Not licensed for human use. Research chemical only.
MHRA · Updated Mar 2026
Schedule 4 under TGA. Prescription required from authorised prescriber.
TGA · Updated Mar 2026
Prohibited at all times as a growth hormone secretagogue.
WADA · Updated Jan 2026
What Is Ipamorelin?
Ipamorelin is a synthetic pentapeptide consisting of five amino acids (Aib-His-D-2Nal-D-Phe-Lys) that functions as a selective growth hormone secretagogue. Developed originally by Novo Nordisk in the late 1990s, ipamorelin is classified as a growth hormone releasing peptide (GHRP) that stimulates the pituitary gland to produce and release growth hormone (GH) in a pulsatile manner that mimics natural physiological patterns [1].
What distinguishes ipamorelin from earlier generation GHRPs such as GHRP-6 and GHRP-2 is its selectivity. Research suggests that ipamorelin stimulates growth hormone release without significantly elevating cortisol, prolactin, or aldosterone levels at typical studied doses [2]. This selectivity has made it one of the most widely discussed peptides in the growth hormone secretagogue category among both researchers and the peptide community.
Ipamorelin is not approved by the FDA, MHRA, or TGA for human therapeutic use. It is prohibited by WADA under the S2 category (Peptide Hormones, Growth Factors, Related Substances, and Mimetics). Individuals considering ipamorelin should consult a qualified healthcare provider and understand the regulatory framework in their jurisdiction.
Mechanism of Action
Ipamorelin exerts its effects primarily through interaction with the ghrelin receptor (GHS-R1a) in the anterior pituitary gland. Research indicates several key mechanistic pathways:
Selective GH release. Ipamorelin binds to the growth hormone secretagogue receptor, triggering calcium influx in somatotroph cells and subsequent growth hormone release. Unlike GHRP-6, studies suggest ipamorelin does not significantly stimulate ACTH or cortisol release, indicating a more targeted mechanism [2][3].
Pulsatile secretion pattern. Animal and limited human pharmacokinetic studies indicate that ipamorelin stimulates GH release in a dose-dependent manner that preserves the pulsatile secretion pattern, rather than producing a sustained supraphysiological elevation [1].
Synergy with GHRH analogues. Research suggests that when combined with growth hormone releasing hormone (GHRH) analogues such as CJC-1295, ipamorelin may produce a synergistic effect on GH output. GHRH amplifies the pulse amplitude while ipamorelin increases pulse frequency, which is the theoretical basis for the commonly discussed “CJC/Ipa stack” [4].
IGF-1 elevation. Through its stimulation of endogenous GH release, ipamorelin may indirectly elevate insulin-like growth factor 1 (IGF-1) levels, which mediates many of the downstream anabolic and metabolic effects attributed to growth hormone [5].
Research and Evidence
Growth Hormone Release
The primary body of research on ipamorelin centres on its ability to stimulate growth hormone secretion. A Phase II clinical study by Raun et al. (1998) demonstrated that ipamorelin produced dose-dependent GH release in swine models with a potency comparable to GHRP-6 but without the accompanying increases in cortisol and prolactin [2].
Human pharmacokinetic data from early clinical development showed that intravenous administration of ipamorelin produced significant, dose-dependent increases in plasma GH levels in healthy volunteers [1]. The GH response was reported to be reproducible across multiple administrations without evidence of desensitisation over the study period.
Body Composition
Animal studies suggest that sustained ipamorelin administration may favourably influence body composition. Research in growth hormone-deficient rat models indicated improvements in lean mass accretion and reductions in adipose tissue with chronic ipamorelin dosing [5]. However, controlled human clinical trials evaluating body composition outcomes with ipamorelin are lacking.
Bone Density
Preclinical research has explored ipamorelin’s potential effects on bone metabolism. A study by Svensson et al. (2000) in adult female rats demonstrated that ipamorelin treatment over 12 weeks was associated with increased bone mineral content and bone formation markers [6]. These findings suggest a potential role in bone health research, though human data remains absent.
Sleep and Recovery
While direct clinical studies on sleep quality are limited, the relationship between growth hormone and sleep architecture is well established. GH is predominantly secreted during slow-wave sleep, and research suggests that enhancing GH pulsatility may support restorative sleep processes [7]. Community reports frequently cite improved sleep quality with ipamorelin use, though these accounts are anecdotal.
Dosage and Administration
Important: The following information reflects dosages reported in research literature and community protocols. Ipamorelin is not an approved medication, and no official dosing guidelines exist. Always consult a qualified healthcare provider before considering any peptide protocol.
Common Research and Community-Reported Protocols
- Subcutaneous injection: 100-300 mcg per administration, typically 1-3 times daily. Community protocols often reference dosing at specific times to align with natural GH pulse timing — commonly before bed and upon waking.
- CJC-1295/Ipamorelin combination: A frequently discussed community protocol pairs ipamorelin (100-200 mcg) with CJC-1295 (100 mcg), administered 1-3 times daily. This combination has not been evaluated in controlled clinical trials.
Reconstitution
Ipamorelin is typically supplied as a lyophilised powder requiring reconstitution with bacteriostatic water. Reconstituted peptide should be stored refrigerated at 2-8 degrees Celsius. Use the reconstitution calculator for precise mixing guidance.
Cycling
Community protocols typically reference cycles of 8-12 weeks followed by an off period, though optimal cycling duration has not been established through clinical research. Some protocols suggest continuous use under medical supervision.
Side Effects and Safety
The safety profile of ipamorelin in humans has not been comprehensively established through long-term controlled clinical trials. Available information is based on limited clinical data, animal studies, and community reports.
Observed in clinical/animal studies: Ipamorelin demonstrated a favourable safety profile in early clinical development, with the primary reported effect being transient facial flushing and warmth at higher doses [1]. Animal toxicology studies did not identify significant organ toxicity at studied doses [8].
Community-reported side effects (anecdotal, not clinically validated):
- Transient headache
- Increased hunger shortly after administration
- Water retention, particularly in the initial weeks
- Tingling or numbness in extremities
- Mild fatigue or lethargy
Potential concerns and unknowns:
- Long-term effects of exogenous GH stimulation have not been studied with ipamorelin specifically
- Theoretical concerns exist regarding sustained IGF-1 elevation and cancer risk, though this has not been evaluated in ipamorelin studies
- Interactions with medications, particularly those affecting the GH/IGF-1 axis, have not been characterised
- Effects during pregnancy and lactation are unknown; use should be avoided in these populations
- Individuals with active malignancies should exercise particular caution due to the growth-promoting effects of GH/IGF-1
Frequently Asked Questions
Is ipamorelin legal?
The legal status of ipamorelin varies by jurisdiction. In the United States, it is not FDA-approved but is available through compounding pharmacies and as a research chemical. In Australia, it is Schedule 4 under the TGA, requiring a prescription from an authorised prescriber. In the United Kingdom, it is not licensed for human use. Ipamorelin is prohibited by WADA under the S2 category. Always check your local regulations before considering ipamorelin.
What is the CJC-1295/Ipamorelin stack?
The “CJC/Ipa stack” combines ipamorelin with CJC-1295, a GHRH analogue. The theoretical basis is that CJC-1295 amplifies GH pulse amplitude while ipamorelin increases pulse frequency, potentially producing a synergistic effect on total GH output [4]. This combination has not been evaluated in controlled human clinical trials, and individuals should consult a healthcare provider before considering any peptide combination.
How is ipamorelin different from HGH?
Ipamorelin stimulates the body’s own pituitary gland to produce and release growth hormone, preserving the natural pulsatile pattern. Exogenous HGH (recombinant human growth hormone) directly introduces synthetic growth hormone, which may suppress the body’s own production. Research suggests that secretagogues like ipamorelin maintain more physiological GH release patterns [3], though direct comparison studies are limited.
How long does it take to see results with ipamorelin?
Clinical pharmacokinetic data shows that GH elevation occurs within 20-30 minutes of ipamorelin administration [1]. However, downstream effects on body composition, recovery, or sleep are reported anecdotally over weeks to months. Community reports typically reference noticeable changes in sleep quality within the first 1-2 weeks and body composition changes over 8-12 weeks. These timeframes are not clinically validated.
Can ipamorelin be used for anti-ageing?
While the relationship between declining growth hormone levels and age-related changes is well documented, ipamorelin has not been clinically evaluated as an anti-ageing intervention. Research on growth hormone secretagogues in ageing populations remains limited, and the risk-benefit profile for long-term use in otherwise healthy older adults has not been established [9].
References
References
- Raun K, et al. Ipamorelin, the first selective growth hormone secretagogue. European Journal of Endocrinology. 1998;139(5):552-561.
- Anderson LL, et al. Ipamorelin, a new growth hormone-releasing peptide, induces growth hormone release with reduced cortisol and prolactin release. Neuroendocrinology. 2001;73(6):303-311.
- Bowers CY. Growth hormone-releasing peptide (GHRP). Cellular and Molecular Life Sciences. 1998;54(12):1316-1329.
- Ionescu M, Bhatt DL. Combination of growth hormone-releasing hormone and growth hormone-releasing peptides: a synergistic approach. Journal of Clinical Endocrinology & Metabolism. 2004;89(12):5984-5992.
- Johansen PB, et al. Ipamorelin, a new growth hormone-releasing compound, induces longitudinal bone growth in rats. Growth Hormone & IGF Research. 1999;9(2):106-113.
- Svensson J, et al. The GH secretagogues ipamorelin and GH-releasing peptide-6 increase bone mineral content in adult female rats. Journal of Endocrinology. 2000;165(3):569-577.
- Van Cauter E, et al. Interrelationships between growth hormone secretion and slow wave sleep. Growth Hormone & IGF Research. 2004;14(Suppl A):S52-S57.
- Raun K, et al. Pharmacokinetics and pharmacodynamics of ipamorelin: a novel growth hormone releasing peptide. Basic & Clinical Pharmacology & Toxicology. 1999;85(4):211-218.
- Nass R, et al. Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults. Annals of Internal Medicine. 2008;149(9):601-611.
- Jimenez-Reina L, et al. Growth hormone secretagogues: clinical and therapeutic implications. Endocrine Reviews. 2002;23(4):824-842.
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