Research Overview
CJC-1295 and ipamorelin get compared because the same literature pairs them, and because they are the clearest case in this catalog of two compounds that look interchangeable and are not: two receptors, two timescales. CJC-1295 is an analog of the first 29 residues of human growth hormone releasing factor, acting at the releasing factor receptor on the anterior pituitary (Jette et al., Endocrinology 2005, PMID 15817669).
Ipamorelin is a pentapeptide secretagogue acting at the growth hormone secretagogue receptor, whose endogenous ligand was later identified as ghrelin (Raun et al., Eur J Endocrinol 1998, PMID 9849822; Kojima et al., Nature 1999, PMID 10604470).
That structure is why the pairing exists at all. In rat primary pituitary cell culture, a hexapeptide secretagogue and the releasing factor produced a synergistic effect on release at maximal concentrations; the secretagogue alone did not raise intracellular cyclic AMP while the releasing factor raised it roughly three fold, and cross-desensitization did not occur, read by the authors as two receptors and two discrete mechanisms (Cheng et al., Endocrinology 1989, PMID 2541999).
Structure and Class
The catalog CJC-1295 No DAC material is a 29-residue amidated analog of human growth hormone releasing factor: C152H252N44O42, approximately 3367.9 g/mol, CAS 863288-34-0, PubChem CID 56841945. The drug affinity complex version adds a maleimide-bearing lysine at the C-terminus and is listed at C165H269N47O46, 3647.06 g/mol on its catalog page, matching PubChem CID 91971820.
Ipamorelin is far smaller: the pentapeptide Aib-His-D-2-Nal-D-Phe-Lys-NH2, C38H49N9O5, approximately 711.9 g/mol, CAS 170851-70-4, PubChem CID 9831659, printed as 711.86 g/mol with the class given as a growth hormone secretagogue. It was identified within a series that removed the central Ala-Trp dipeptide of GHRP-1, and it holds two non-natural residues and two D-amino acids, so it is not a fragment of any human protein (Raun et al., Eur J Endocrinol 1998, PMID 9849822).
The mass ratio is close to five to one, so a vial at the same milligram strength holds roughly five times as many molecules of ipamorelin as of the releasing factor analog. Salt form and net peptide content are certificate values for the lot.
Side by Side
| Attribute | CJC-1295 (No DAC) | Ipamorelin |
|---|---|---|
| Compound class | Releasing factor analog, 29 residues, amidated | Growth hormone secretagogue, synthetic pentapeptide |
| Origin | Substituted analog of human releasing factor residues 1 to 29 | Designed series lacking the central Ala-Trp of GHRP-1 |
| Identity data | C152H252N44O42, approximately 3367.9 g/mol, CAS 863288-34-0 | C38H49N9O5, approximately 711.9 g/mol, CAS 170851-70-4 |
| Receptor as reported | Releasing factor receptor on the anterior pituitary; raises cyclic AMP | Secretagogue receptor of the ghrelin system; no cyclic AMP rise in the cited cell work |
| Reported duration | Albumin-binding version: half-life 5.8 to 8.1 days in healthy adults | Terminal half-life about 2 hours in healthy volunteers |
| Study models cited | Cultured rat pituitary cells, rats, knockout mice, healthy human adults | Rat pituitary cells, rats, conscious swine, healthy volunteers, a phase 2 trial |
| Supplied form | Lyophilized powder, single vial, also in a blend with ipamorelin | Lyophilized powder, single vial, also in blends |
Research Context: CJC-1295
The compound came out of a bioconjugation program. Maleimido derivatives of releasing factor residues 1 to 29 were conjugated to human serum albumin, resisted dipeptidylpeptidase-IV in vitro and stayed bioactive in a secretion assay in cultured rat anterior pituitary cells. The best derivative gave a four fold increase in area under the curve over two hours in rats, was detectable in plasma beyond 72 hours, and was named CJC-1295 (Jette et al., Endocrinology 2005, PMID 15817669). Models: rat cell culture and rats.
Human pharmacology followed in two placebo-controlled dose-ascending trials. A single administration in these trials produced dose-dependent increases in mean plasma growth hormone of two to ten fold lasting six days or more, and IGF-I increases of 1.5 to three fold lasting nine to eleven days, with an estimated half-life of 5.8 to 8.1 days (Teichman et al., J Clin Endocrinol Metab 2006, PMID 16352683).
A follow-up sampled overnight at 20-minute intervals in healthy men a week after a single administration and found pulsatility preserved, pulse frequency and magnitude unaltered while trough levels rose about 7.5 fold (Ionescu et al., J Clin Endocrinol Metab 2006, PMID 17018654). Model: healthy human adults.
The clearest interval evidence is a mouse genetics experiment. In releasing hormone knockout mice treated for five weeks, animals dosed every 24 hours reached normal body weight and length while 48-hour and 72-hour intervals improved growth without normalizing it (Alba et al., Am J Physiol Endocrinol Metab 2006, PMID 16822960). Model: knockout mouse.
Research Context: Ipamorelin
The founding paper established potency and selectivity together. Ipamorelin released growth hormone from primary rat pituitary cells with potency similar to GHRP-6, worked through a secretagogue-like receptor rather than the releasing factor receptor in antagonist profiling, and released growth hormone in rats and conscious swine. The notable result was negative: in swine it did not raise ACTH or cortisol above levels seen with the releasing factor, while GHRP-6 and GHRP-2 both did (Raun et al., Eur J Endocrinol 1998, PMID 9849822). Models: rat cell culture, rats, swine.
A growth-plate study in adult female rats reported a dose-dependent increase in longitudinal growth rate by tetracycline labelling in the proximal tibia, from 42 to 52 micrometres per day, with no change in total IGF-I or serum markers of bone turnover (Johansen et al., Growth Horm IGF Res 1999, PMID 10373343). Model: rat.
Human pharmacokinetics are short and well described: a dose-escalation trial across five infusion rates in healthy male volunteers reported dose-proportional kinetics, a terminal half-life of about two hours, and a single episode of release peaking near 40 minutes (Gobburu et al., Pharm Res 1999, PMID 10496658). Model: healthy human volunteers.
Ipamorelin also has something CJC-1295 does not: a completed randomized controlled trial with a clinical endpoint. In a double-blind, placebo-controlled phase 2 study in 114 adults after bowel resection, ipamorelin was well tolerated but produced no significant difference from placebo in time to tolerance of a standardized solid meal, 25.3 hours against 32.6 (Beck et al., Int J Colorectal Dis 2014, PMID 25331030).
Choosing Between Them for a Research Question
Choose by receptor and timescale. A design probing the releasing factor receptor, cyclic AMP signaling in somatotrophs or exposure-interval effects has precedent with CJC-1295. A design probing the secretagogue receptor, acute pulsatile release, selectivity against ACTH and cortisol, or short-half-life kinetics has precedent with ipamorelin.
The pairing question is separate. The cell-culture basis for combining the two classes is the 1989 synergy finding of two receptors and a supra-additive effect at maximal concentrations (Cheng et al., Endocrinology 1989, PMID 2541999): an in-vitro rationale for a combination design, not evidence of a combined outcome. The catalog stocks a fixed blend for designs needing both; single-compound vials are the right choice when an effect has to be attributed to one of them. Neither compound is approved for any performance or physique use, and both sit under anti-doping prohibition in regulated sport.
Handling and Storage
Both arrive lyophilized and should stay that way until use. Keep sealed vials cold and dark, let them reach room temperature before opening so moisture does not condense onto the cake, add diluent gently down the vial wall, and let the powder dissolve rather than shaking it. The Disguised Alpha pages for both state minus 20 C for the powder as shipped and 2 to 8 C after reconstitution, protected from light, freeze-thaw cycles avoided.
Size changes the practical risk. The 29-residue analog is the more fragile: longer chains aggregate more readily under agitation and heat. Ipamorelin is a capped pentapeptide, a sturdier construct though no more tolerant of freeze-thaw. For either, aliquot into single-use volumes, label them with the lot number, and take the molecular weight for molarity from the certificate.
Questions Researchers Ask
Do CJC-1295 and ipamorelin act on the same receptor?
No. CJC-1295 acts at the releasing factor receptor on the anterior pituitary (Jette et al., Endocrinology 2005, PMID 15817669). Ipamorelin acts at the growth hormone secretagogue receptor, whose endogenous ligand is ghrelin (Raun et al., Eur J Endocrinol 1998, PMID 9849822; Kojima et al., Nature 1999, PMID 10604470).
How different are the reported half-lives?
Very. The albumin-binding version of CJC-1295 had an estimated half-life of 5.8 to 8.1 days in healthy adults (Teichman et al., J Clin Endocrinol Metab 2006, PMID 16352683), while ipamorelin showed about two hours (Gobburu et al., Pharm Res 1999, PMID 10496658). A comparison has to account for that gap in its sampling schedule.
Is there a controlled human trial for either?
Ipamorelin has one: a phase 2 randomized placebo-controlled study in 114 bowel-resection patients that missed its primary endpoint (Beck et al., Int J Colorectal Dis 2014, PMID 25331030). CJC-1295 has placebo-controlled pharmacodynamic trials reporting hormone concentrations rather than clinical endpoints (Teichman et al., J Clin Endocrinol Metab 2006, PMID 16352683).
What should be confirmed on the certificate?
Printed lot identity, which CJC-1295 form the lot contains, HPLC purity against specification, identity confirmation, measured net peptide content, and the salt form.
CJC-1295 and ipamorelin are supplied strictly for laboratory and in-vitro research use. They are not for human consumption, veterinary use, or any diagnostic or therapeutic application. Nothing on this page is medical, dosing, or therapeutic advice.