Independent editorial projectupdated September 21, 2026
CJC-1295 ipamorelin: what the published studies actually show
Two peptides, two receptors, one axis. This site reads the peer-reviewed record on CJC-1295 and ipamorelin so that you do not have to take a clinic page or a forum thread at its word. Every number has a DOI on the same page.
5.8 to 8.1 dhalf-life of CJC-1295 with DAC in healthy adults
2 hterminal half-life of ipamorelin in men
×7.5trough GH one week after one CJC-1295 dose
0human trials of the two given together
Two molecules that do not do the same thing
The phrase "CJC-1295 ipamorelin" names a pair, not a compound. CJC-1295 was built at ConjuChem in Montreal as a growth-hormone-releasing hormone (GHRH) fragment that would last longer than the native hormone: four amino acids were swapped to resist enzymatic cleavage, and a maleimide group was added on a thirtieth lysine so that the peptide binds covalently to cysteine 34 of serum albumin after injection [Jetté et al., 2005]. That linker is the "DAC", and it is why the human half-life came out at 5.8 to 8.1 days [Teichman et al., 2006].
Ipamorelin came out of a different programme, at Novo Nordisk in Denmark. It is five residues long, it binds the receptor that ghrelin later turned out to occupy, and it was selected precisely because it released GH without the cortisol and prolactin that earlier GHRPs also released [Raun et al., 1998]. Its terminal half-life in men is about 2 hours [Gobburu et al., 1999].
The vial sold under the combined name in the research market almost always contains the linker-free version of CJC-1295, called Mod GRF 1-29 on forums, together with ipamorelin. If the reason for that choice is not obvious, the guide on CJC-1295 DAC versus no DAC walks through it: a linker designed to keep a peptide in the blood for a week has no logic next to a peptide cleared in two hours.
Why the two are studied together
Growth hormone is released in pulses, mostly at night. A GHRH-type peptide raises the amount available for each pulse; a GHRP-type peptide acts through a second receptor, the one ghrelin binds, and the two effects add up to more than either alone. In 1990, Bowers and colleagues gave 18 normal men GHRP-6 alone, GHRH(1-44) alone, and the two together: the submaximal doses of GHRP-6 combined with 1 µg/kg GHRH released GH synergistically, more than the sum of the two alone [Bowers et al., 1990]. Every "stack" argument since then rests on that observation.
Schematic redrawn from the results reported by Ionescu and Frohman, 2006 (doi:10.1210/jc.2006-1702): 20-minute sampling over 12 hours in healthy men, trough GH increased 7.5-fold, mean GH 46 %, IGF-1 45 %, pulse number and amplitude unchanged. The curve shapes are illustrative; the ratios are the published ones.
The second thing the record shows is that a long-acting GHRH analogue does not flatten the rhythm. Ionescu and Frohman sampled blood every 20 minutes through the night before and one week after a single injection of CJC-1295: the pulses kept their number and their height, the trough between them rose 7.5-fold, mean GH rose 46 % and IGF-1 45 % [Ionescu et al., 2006]. The mechanism, the receptors and the vocabulary are laid out in what is CJC-1295 ipamorelin.
ipamorelin 0.03 mg/kg IV twice daily, up to 7 days
adverse events 87.5 % vs 94.8 % placebo; primary endpoint not met (p = 0.15)
That is the whole human record for the two molecules: two trials for CJC-1295, one pharmacokinetic study and two phase 2 trials for ipamorelin, one of which has never published its results. The doses used in each are tabulated, with the DOI beside each figure, in the dosage guide. What the trials recorded as adverse events is in CJC-1295 side effects and ipamorelin side effects.
What is not known
Three gaps matter more than the rest. First, the combination has never been given to people in a published trial, so any claim about "CJC-1295 ipamorelin results" is an extrapolation from separate studies. Second, the linker-free CJC-1295 that fills the research vials has no human pharmacokinetic study of its own; its clearance is inferred from the parent GHRH(1-29) sequence. Third, both development programmes stopped: ConjuChem's phase 2 trial in HIV-associated visceral fat was terminated in 2006, and Helsinn's 320-patient ipamorelin trial completed in 2014 without posting results. The CJC-1295 peptide and ipamorelin peptide guides tell each story to its end.
Regulatory status follows from that. Neither molecule is approved by the FDA or the EMA. In September 2023 the FDA placed ipamorelin acetate in category 2 of its list of compounding bulk substances that may present significant safety risks, on the ground of possible immunogenicity [U.S., 2023], and both molecules are named in class S2 of the WADA Prohibited List [World, 2026]. Tesamorelin, a cousin of CJC-1295 that did complete its programme, is the useful counter-example: CJC-1295 ipamorelin versus tesamorelin.
What is in a "CJC-1295 ipamorelin" vial
In the research-use market the combined name designates one lyophilized vial holding both peptides in equal mass, typically 5 mg of Mod GRF 1-29 and 5 mg of ipamorelin in a 10 mg vial. Because the two molecules differ in mass by a factor of almost five (3,367.9 against 711.9 g/mol), equal mass means about 4.7 molecules of ipamorelin for every molecule of the GHRH analogue. A certificate of analysis for such a vial has to show two HPLC peaks and two masses, one of them 3,368 rather than 3,647, or the vial is not what its label says. The for-sale guide lists the nine things a listing must state, and it is why this site links to a single supplier page: the blend at OXpeptides publishes that certificate per lot.
CJC-1295 Ipamorelin Review is an independent editorial project with no clinic, no shop and no newsletter. Each article opens with four citable facts, quotes only doses and figures that appear in a peer-reviewed paper or a registered trial, and lists its sources with a DOI that returned HTTP 200 on CrossRef on the day of publication. The method, the correction policy and a contact address are on the about page and in the editorial policy.
Sources
Each DOI below returned HTTP 200 on api.crossref.org and each NCT number on clinicaltrials.gov when this page was last updated. Nothing is cited from memory.
Teichman SL, Neale A, Lawrence B, Gagnon C, Castaigne JP, Frohman LA (2006). 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 91(3):799-805. doi:10.1210/jc.2005-1536CrossRef 200 Two randomized, placebo-controlled, double-blind ascending-dose trials (28 and 49 days) in healthy adults aged 21 to 61. Four ascending single doses in the first study (30 and 60 µg/kg named as the best tolerated); two or three weekly or biweekly doses in the second. Half-life 5.8 to 8.1 days.1
Ionescu M, Frohman LA (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 91(12):4792-4797. doi:10.1210/jc.2006-1702CrossRef 200 Overnight 12-hour sampling every 20 minutes in healthy men aged 20 to 40, before and one week after a single 60 or 90 µg/kg injection. Trough GH up 7.5-fold, mean GH up 46 %, IGF-1 up 45 %, pulse frequency and amplitude unchanged.2
Raun K, Hansen BS, Johansen NL, Thøgersen H, Madsen K, Ankersen M, Andersen PH (1998). Ipamorelin, the first selective growth hormone secretagogue. European Journal of Endocrinology 139(5):552-561. doi:10.1530/eje.0.1390552CrossRef 200 The Novo Nordisk paper that describes ipamorelin (Aib-His-D-2-Nal-D-Phe-Lys-NH2). EC50 1.3 nmol/l in rat pituitary cells, ED50 2.3 nmol/kg in swine, no ACTH or cortisol release at more than 200 times the GH ED50, no effect on FSH, LH, PRL or TSH.3
Gobburu JV, Agersø H, Jusko WJ, Ynddal L (1999). Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers. Pharmaceutical Research 16(9):1412-1416. doi:10.1023/A:1018955126402CrossRef 200 Five intravenous infusion rates (4.21 to 140.45 nmol/kg over 15 minutes) in eight healthy men per dose level. Terminal half-life 2 hours, clearance 0.078 l/h/kg, one GH episode peaking at 0.67 hours, SC50 214 nmol/l.4
Beck DE, Sweeney WB, McCarter MD, Ipamorelin 201 Study Group (2014). 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 29(12):1527-1534. doi:10.1007/s00384-014-2030-8CrossRef 200NCT00672074CT.gov 200 Phase 2, multicentre, double-blind, placebo-controlled. 117 enrolled, 114 analysed. Intravenous 0.03 mg/kg twice daily for up to 7 days. Adverse events in 87.5 % (ipamorelin) versus 94.8 % (placebo). Median time to first tolerated meal 25.3 versus 32.6 hours, p = 0.15.5
Bowers CY, Reynolds GA, Durham D, Barrera CM, Pezzoli SS, Thorner MO (1990). Growth hormone (GH)-releasing peptide stimulates GH release in normal men and acts synergistically with GH-releasing hormone. Journal of Clinical Endocrinology & Metabolism 70(4):975-982. doi:10.1210/jcem-70-4-975CrossRef 200 18 normal men. GHRP-6 at 0.1, 0.3 and 1.0 µg/kg gave peak GH of 7.6, 16.5 and 68.7 µg/l versus 1.2 µg/l with placebo; submaximal GHRP-6 plus 1 µg/kg GHRH(1-44) released GH synergistically. Facial flushing in 16 of 18 subjects after GHRH.6
Jetté L, Léger R, Thibaudeau K, Benquet C, Robitaille M, Pellerin I, Paradis V, van Wyk P, Pham K, Bridon DP (2005). Human growth hormone-releasing factor (hGRF)1-29-albumin bioconjugates activate the GRF receptor on the anterior pituitary in rats: identification of CJC-1295 as a long-lasting GRF analog. Endocrinology 146(7):3052-3058. doi:10.1210/en.2004-1286CrossRef 200 The ConjuChem paper that names CJC-1295: a tetrasubstituted hGRF(1-29) with a maleimidopropionamide lysine at the C-terminus that binds Cys34 of serum albumin. In rats, 4-fold GH area under the curve versus hGRF(1-29) over 2 hours, detectable in plasma beyond 72 hours.7
U.S. Food and Drug Administration (2023). Certain bulk drug substances for use in compounding that may present significant safety risks. FDA, Human Drug Compounding. www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-s… Ipamorelin acetate placed in category 2 on September 29, 2023, with the wording that compounded drugs containing it may pose a risk for immunogenicity for certain routes of administration. The CJC-1295 nomination appears on the same page among the nominations later withdrawn.8
World Anti-Doping Agency (2026). The Prohibited List, class S2 (peptide hormones, growth factors, related substances and mimetics). WADA. www.wada-ama.org/en/prohibited-list… GHRH analogues (CJC-1295, sermorelin, tesamorelin) and growth hormone secretagogues (ipamorelin and the GHRPs) are listed by name as prohibited at all times.9
Questions readers ask
What is CJC-1295 ipamorelin?
A pairing of two synthetic peptides that act on two different pituitary receptors. CJC-1295 is a modified fragment of growth-hormone-releasing hormone (GHRH) that binds the GHRH receptor; ipamorelin is a five-residue peptide that binds the ghrelin receptor (GHS-R1a). In the research-chemical market the name usually refers to a single vial holding the linker-free form of CJC-1295 (Mod GRF 1-29) and ipamorelin in equal mass.
Has the CJC-1295 ipamorelin combination itself been tested in a human trial?
No. Each molecule has its own human data (two JCEM trials for CJC-1295 with DAC, a pharmacokinetic study and two phase 2 trials for ipamorelin), and the principle of pairing a GHRH-type peptide with a GHRP-type peptide was shown in 1990 with GHRH(1-44) and GHRP-6. No peer-reviewed trial has administered the two together.
Is CJC-1295 ipamorelin approved by the FDA?
No. Neither peptide is an approved drug in the United States or in the European Union. In September 2023 the FDA placed ipamorelin acetate in category 2 of its compounding bulk-substances list, citing a possible immunogenicity risk. Both are prohibited in sport under class S2 of the WADA list.
How long does CJC-1295 stay in the body?
With the DAC linker, the published human half-life is 5.8 to 8.1 days, and IGF-1 stayed above baseline for up to 28 days after repeated doses. Without the linker (Mod GRF 1-29) no human pharmacokinetic study has been published; the parent GHRH(1-29) sequence is cleared within minutes. Ipamorelin has a terminal half-life of about 2 hours.
Informational content, not medical advice. CJC-1295 and ipamorelin are investigational research compounds, not approved by the FDA or the EMA for any use.
