CJC-1295 vs ipamorelin
CJC-1295 and ipamorelin are both studied as stimulators of growth hormone (GH) release, but they act on different receptors and have very different time courses 2,3,4. CJC-1295 is a long-acting analog of GH-releasing hormone (GHRH) that binds albumin after administration 1,2. Ipamorelin is a pentapeptide agonist of the ghrelin (GHRP-type) receptor with a short half-life in humans 3,4,5. The published human literature for both is small, and neither has an approved medical use in the sources reviewed 1,5,6.
Side by side
| Field | CJC-1295 (with DAC) | Ipamorelin |
|---|---|---|
| Class | Long-acting GHRH analog 1,2 | Synthetic pentapeptide ghrelin-receptor (GH secretagogue) agonist 3,5 |
| Origin and structure | Synthetic GHRH analog that binds permanently to endogenous albumin after injection, extending its duration of action 2 | Pentapeptide Aib-His-D-2-Nal-D-Phe-Lys-NH2, identified in a medicinal-chemistry series derived from GHRP-1 3 |
| Proposed mechanism | Continuous GHRH-type stimulation; in healthy men GH pulsatility was preserved while trough and mean GH rose 2 | Stimulates GH release through a GHRP-like receptor; in swine (animal data) it did not raise ACTH or cortisol above levels seen with GHRH, unlike GHRP-6 and GHRP-2 3 |
| Half-life | Estimated 5.8 to 8.1 days in healthy adults 1; about 8 days in a second report 2 | Terminal half-life about 2 hours after intravenous infusion in healthy men 4 |
| Highest human trial phase | Early-phase randomized, placebo-controlled, ascending-amount trials in healthy adults 1; no later-phase trials identified | Phase 2 randomized, placebo-controlled trial in postoperative ileus (intravenous) 5 |
| FDA status | Listed by the FDA among bulk substances for compounding that may present significant safety risks; FDA identified serious adverse events including increased heart rate and systemic vasodilatory reaction, and notes limited clinical data 6 | Ipamorelin acetate is listed on the same FDA page, citing immunogenicity, peptide characterization complexity and a published study reporting serious adverse events including death after intravenous use for gastric motility 6 |
| Published human outcomes | After a single administration in healthy adults, mean GH rose 2- to 10-fold for 6 days or more and IGF-I 1.5- to 3-fold for 9 to 11 days 1; in a separate study, mean GH rose 46% and IGF-I 45% 2 | Healthy men showed a single episode of GH release peaking near 0.67 hours 4. In 114 analyzed ileus patients, median time to first tolerated meal was 25.3 h vs 32.6 h with placebo, not a significant difference (p = 0.15) 5 |
| Safety signals | No serious adverse reactions were reported in the two healthy-adult trials 1; FDA cites heart-rate and vasodilatory events 6 | Treatment-emergent adverse events occurred in 87.5% (ipamorelin) vs 94.8% (placebo) of ileus patients 5; FDA cites a published study with serious adverse events including death after intravenous use 6 |
| WADA status | Named under S2.2.4 as a GHRH analogue; prohibited at all times 7 | Named under S2.2.4 as a GH secretagogue or mimetic; prohibited at all times 7 |
| Evidence level | Small human pharmacology studies in healthy adults 1,2 | Animal pharmacology, healthy-volunteer pharmacokinetics and one phase 2 trial without a significant efficacy difference 3,4,5 |
CJC-1295 (with DAC): what the data says
CJC-1295 has been examined in two randomized, placebo-controlled, ascending-amount trials in healthy adults aged 21 to 61 1. After a single subcutaneous administration, mean plasma GH concentrations rose 2- to 10-fold for 6 days or more and IGF-I rose 1.5- to 3-fold for 9 to 11 days, and IGF-I stayed above baseline for up to 28 days after repeated administrations 1. No serious adverse reactions were reported in those trials 1.
In a separate study of healthy men aged 20 to 40, overnight sampling one week after a single administration showed preserved GH pulse frequency and magnitude, a 7.5-fold increase in trough GH, and increases of 46% in mean GH and 45% in IGF-I 2. The authors noted that the IGF-I increase did not correlate with any measured GH secretion parameter 2. No later-phase trials were identified.
Ipamorelin: what the data says
Ipamorelin was characterized in a 1998 preclinical report 3. In rat pituitary cells and in anesthetized rats (cell and animal data), it released GH with potency and efficacy comparable to GHRP-6, and in swine it did not raise ACTH or cortisol above levels seen with GHRH, whereas GHRP-6 and GHRP-2 did 3.
In healthy men receiving intravenous infusions, ipamorelin showed a terminal half-life of about 2 hours and a single episode of GH release that peaked near 0.67 hours 4. In a phase 2 trial of 117 patients undergoing bowel resection, intravenous ipamorelin did not differ significantly from placebo on time to first tolerated meal or on secondary efficacy analyses 5. The FDA page notes that a published study reported serious adverse events including death when ipamorelin was given intravenously for gastric motility 6.
Key research differences
- Receptor target: CJC-1295 is a GHRH analog, while ipamorelin acts through a ghrelin/GHRP-type receptor 2,3.
- Duration: the estimated half-life of CJC-1295 is 5.8 to 8.1 days in healthy adults, versus about 2 hours for ipamorelin in healthy men 1,4.
- GH pattern: CJC-1295 raised trough and mean GH while preserving pulses 2, whereas ipamorelin produced a single episode of GH release in healthy men 4.
- Patient trials: ipamorelin has a phase 2 trial in postoperative ileus with no significant efficacy difference 5; no patient trials of CJC-1295 were identified.
- FDA-cited concerns differ: increased heart rate and systemic vasodilatory reaction for CJC-1295, and a published study with serious adverse events including death after intravenous use for ipamorelin 6.
- Both are named in WADA class S2.2.4 and are prohibited at all times 7.
Where the evidence is limited
Evidence for both compounds is limited 1,5. The CJC-1295 data come from small studies in healthy adults published in 2006 and measure hormone levels rather than clinical outcomes 1,2. The ipamorelin ileus trial was small and enrolled patients with a broad range of underlying conditions, and its report describes it as proof of concept 5. No head-to-head human comparison of the two compounds was identified. The FDA notes that clinical data on CJC-1295 are limited 6.
Frequently asked questions
How do CJC-1295 and ipamorelin differ mechanistically?
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Has either compound been tested in patients?
What has the FDA said about them?
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References
- Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults Journal of Clinical Endocrinology & Metabolism. 2006
- Pulsatile secretion of growth hormone (GH) persists during continuous stimulation by CJC-1295, a long-acting GH-releasing hormone analog Journal of Clinical Endocrinology & Metabolism. 2006
- Ipamorelin, the first selective growth hormone secretagogue European Journal of Endocrinology. 1998
- Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers Pharmaceutical Research. 1999
- Prospective, randomized, controlled, proof-of-concept study of the ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients International Journal of Colorectal Disease. 2014
- Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (Category 2; content current as of 04/22/2026) FDA (Human Drug Compounding). 2026
- International Standard: Prohibited List 2026 WADA. 2026
For research use only. Not for human or veterinary use. Not a drug, food, or dietary supplement. This page compares published research and is not medical advice or a recommendation.