What is the half-life of ipamorelin?
Ipamorelin‘s published plasma half-life in human volunteer trials is approximately 2 hours, with a single growth-hormone-release pulse following each dose. The short half-life is intentional to the pharmacological design — pulsatile GH release that mirrors natural pituitary-rhythm patterns rather than sustained elevation.
What the research literature says
Ipamorelin was developed by the Novo Nordisk research program specifically as a selective growth hormone secretagogue with a pharmacokinetic profile supporting pulsatile rather than continuous GH release. The Raun characterisation paper established the compound as the first GH secretagogue with high selectivity for GH release relative to cortisol, prolactin, and ACTH (PMID 9849822). The Johansen pharmacokinetic study covered the absorption, distribution, and elimination profile including the ~2-hour terminal half-life (PMID 9879640).
The short half-life supports a pharmacological strategy distinct from the long-acting GHRH-analogue compounds. Where the long-acting GHRH analogues (CJC-1295 DAC, with a ~6-8 day half-life) produce sustained pituitary stimulation and a flattened GH-release pattern, ipamorelin produces a single discrete GH pulse following each dose, with plasma GH returning to baseline within hours. The pulsatile pattern is hypothesised to better mirror the natural pituitary rhythm and avoid the receptor-desensitisation issues seen with sustained agonism.
Subsequent work has examined ipamorelin in postoperative-ileus research contexts (PMID 19289567, PMID 25331030) where the prokinetic activity in addition to GH-secretagogue pharmacology is operative. The Beck human proof-of-concept trial used a multi-dose protocol with the dosing interval set to maintain the pulsatile pharmacology rather than to extend GH elevation through accumulation.
Why this matters in research context
The pulsatile-vs-sustained GH-release distinction is the central design choice in the GH-axis research-peptide class. Ipamorelin sits on the pulsatile end (~2-hour half-life, discrete GH pulse per dose); CJC-1295 No DAC also sits on the pulsatile end (~30-minute half-life, sharp brief GH pulse); CJC-1295 DAC sits on the sustained end (~6-8 day half-life, continuous receptor stimulation). The choice of compound and dosing interval for a research protocol depends on which pattern the researcher wants to model.
Related compounds
- Ipamorelin 10mg — the compound covered by this answer
- CJC-1295 No DAC 10mg — complementary pulsatile-pharmacology GHRH analogue
- CJC-1295 + Ipamorelin blend — single-vial co-formulation engaging GHRH and ghrelin receptors simultaneously
Related research questions
- What is the half-life of CJC-1295 No DAC?
- What is the half-life of tesamorelin?
- Can CJC-1295 be stacked with ipamorelin?
References
- Raun K et al. Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol 1998;139(5):552-561. [PMID 9849822]
- Johansen PB et al. Pharmacokinetic evaluation of ipamorelin and other peptidyl growth hormone secretagogues with emphasis on nasal absorption. Xenobiotica 1998;28(11):1083-1095. [PMID 9879640]
- Venkova K et al. Efficacy of ipamorelin, a novel ghrelin mimetic, in a rodent model of postoperative ileus. J Pharmacol Exp Ther 2009;329(3):1110-1116. [PMID 19289567]
Research-questions pages describe research-context use of peptide-research terminology. They do not constitute medical, veterinary, or clinical advice. Ipamorelin is sold strictly as a research-grade reagent for laboratory and bench research applications.