CJC-1295 vs ipamorelin

CJC-1295 and ipamorelin differ in receptor, size and duration. CJC-1295 is a modified 29-residue GHRH fragment with an albumin-binding lysine, lasting days in human studies. Ipamorelin is a five-residue ghrelin receptor agonist cleared within hours. Both release growth hormone (GH) from the pituitary, through separate receptors. ^[4][11]

The two molecules come from different chemistry programmes. Ipamorelin came first. Novo Nordisk researchers in Denmark described it in 1998 as a pentapeptide, Aib-His-D-2-Nal-D-Phe-Lys-NH2, found in a series of compounds that lacked the central Ala-Trp dipeptide of GHRP-1. ^[11] CJC-1295 followed in 2005 from ConjuChem in Montreal, described as "a tetrasubstituted form of hGRF(1-29)" with a maleimidopropionamide lysine added at the C-terminus. ^[4]

The added lysine is what makes CJC-1295 last. Its maleimide group attaches to the free thiol on Cys34 of serum albumin, and in rats CJC-1295 stayed in plasma beyond 72 hours. ^[4] Ipamorelin carries no such group. The full CJC-1295 story, including the shorter version sold "without DAC", is in our CJC-1295 explainer.

CJC-1295 is about 5.1 times heavier than ipamorelin, lasts days where ipamorelin lasts hours, and has a smaller but longer human record. The table puts both compounds on the same rows.

Identifiers come from PubChem, which we checked on 29 September 2026. ^[1][7] Half-lives come from the 2006 CJC-1295 trials and the 1999 ipamorelin study. ^[2][3] Scheduling comes from the June 2026 Poisons Standard, ^[9] and sport status from the WADA 2026 List. ^[10] Prices are in Australian dollars.

Two cautions sit behind the table. The Poisons Standard lists CJC-1295 with CAS 863288-34-0, and PubChem assigns that number to a separate 29-residue record without the albumin-binding lysine, at 3367.9 g/mol. ^[12] And the two half-lives come from different study designs and populations, so the gap between them (days against hours) is the useful fact. A precise ratio would overstate what the studies measured.

CJC-1295 activates the GHRH receptor on the anterior pituitary, and albumin binding keeps it in circulation for days. The 2005 discovery paper reported that its albumin conjugates were active in a GH secretion assay in cultured rat pituitary cells, and in rats it gave a 4-fold increase in GH area under the curve over 2 hours against hGRF(1-29). ^[4]

The human work is two 2006 papers. In two randomised, placebo-controlled, double-blind trials in healthy adults aged 21 to 61, lasting 28 and 49 days, mean GH rose 2- to 10-fold for 6 days or more and IGF-I rose 1.5- to 3-fold for 9 to 11 days. ^[2] A second study in healthy men aged 20 to 40 asked whether constant stimulation flattened GH's natural pulses. The frequency and size of pulses were unaltered, while trough GH rose 7.5-fold, mean GH 46% and IGF-I 45%. ^[13]

In GHRH-knockout mice treated from 1 week old for 5 weeks, the most frequent schedule gave normal body weight and length, and the pituitary showed more GH mRNA. ^[14] All of these are hormone and growth measurements in small groups or animals.

Ipamorelin activates the ghrelin receptor, the receptor GHRP-6 acts on, and releases a single short pulse of GH. In the 1998 discovery work, ipamorelin released GH from primary rat pituitary cells with potency and efficacy similar to GHRP-6. Tests with GHRP and GHRH antagonists showed that it acts through a GHRP-like receptor. ^[11]

Its defining finding is selectivity. In conscious swine, GHRP-6 and GHRP-2 raised ACTH and cortisol, while ipamorelin did not release ACTH or cortisol at levels significantly different from GHRH stimulation. That held even at exposures more than 200-fold above the level giving half-maximal GH release, and none of the compounds tested changed FSH, LH, prolactin or TSH. ^[11] The authors called it the first GHRP-receptor agonist with a GH selectivity similar to GHRH.

In healthy men, the 1999 study used five exposure levels with eight men at each. It reported a terminal half-life of 2 hours and a single episode of GH release peaking at 0.67 hours, then falling to negligible levels. ^[3] Rat work adds that ipamorelin was cleared 5-fold more slowly than GHRP-6 and was mainly excreted in urine. ^[15]

Later papers use the receptor name directly. A 2009 rat study described ipamorelin as "a selective growth hormone secretagogue and agonist of the ghrelin receptor", ^[16] and a 2024 ferret study grouped it with anamorelin as a growth hormone secretagogue receptor 1a agonist. ^[5]

No published study has compared CJC-1295 and ipamorelin directly. We searched PubMed on 29 September 2026 for records naming both and found 10: nine reviews or scoping reviews published in 2026, and a 2013 Hong Kong Jockey Club method for detecting seven peptides in horse plasma. ^[8]

That horse-plasma paper is the only primary study naming both, and it measured detection. It extracted GHRP-1, GHRP-2, GHRP-6, ipamorelin, hexarelin, CJC-1295 and the TB-500 fragment from horse plasma, with detection limits below 50 pg/mL for all seven. ^[17] It says nothing about how the two compounds act.

The closest comparisons in the literature set each compound against its own parent class:

1. Ipamorelin against GHRP-6, GHRP-2 and GHRH in rat cells, rats and swine (1998), where it matched GHRP-6 on GH release and differed on ACTH and cortisol. ^[11]
2. CJC-1295 against hGRF(1-29) in rats (2005), where it gave 4 times the GH area under the curve over 2 hours. ^[4]

The reviews summarise what exists. A 2026 scoping review of six research peptides, including both, found that 67% of identified publications used animal models and that human studies were few and mostly lacked robust controls. ^[18]

No published study has tested CJC-1295 and ipamorelin as a pair. The pairing rests on older human studies of the two receptor classes, using related molecules.

In 1990, a Tulane group gave a GH-releasing hexapeptide and GHRH to 18 normal men. Submaximal amounts of the peptide combined with GHRH released GH synergistically, and the authors concluded the two act independently. ^[6] A 2001 Kyoto study reported the same synergy between ghrelin and GHRH in normal men, with no synergy on ACTH or prolactin. ^[19] Neither study used CJC-1295 or ipamorelin, so the synergy describes the receptor classes.

Sellers offer both compounds in one vial. Our CJC-1295 + Ipamorelin vial holds 10mg in total for A$108 and has its own batch certificate. A combined vial makes the certificate more demanding: the identity section should report a mass for each compound, near 711.9 g/mol for ipamorelin and near 3647.2 g/mol for CJC-1295 with its albumin-binding lysine, or 3367.9 g/mol for the shorter form without it. ^[1][12][7]

The 2006 CJC-1295 trials in healthy adults reported no serious adverse reactions, and the abstract lists no milder events. ^[2] The only controlled ipamorelin trial reporting adverse events found treatment-emergent events in 87.5% of the ipamorelin group and 94.8% of the placebo group, in adults recovering from bowel surgery. ^[20]

For CJC-1295, the published record shows:

• Healthy-adult trials (2006). No serious adverse reactions were reported across the 28- and 49-day trials. ^[2]
• GH pulse study (2006). The abstract contains no safety statement. ^[13]

For ipamorelin:

• Phase 2 trial in postoperative ileus (2014). Of 117 adults enrolled after small or large bowel resection, 114 formed the safety population. Both arms were recovering from bowel surgery. The trial found no significant difference against placebo on its efficacy measures. ^[20]
• Healthy-volunteer study (1999). The abstract contains no safety statement. ^[3]
• Swine (1998). Ipamorelin did not raise ACTH or cortisol beyond GHRH levels, and did not change FSH, LH, prolactin or TSH. ^[11]

Three sources cover both compounds together. A 2026 narrative review of research-market peptides on the GH-IGF-1 axis, naming both, lists adverse effects reported across that class: prolactin and cortisol elevations, appetite changes, dysglycaemia, fluid retention and myalgia or arthralgia. ^[21] The review does not assign each effect to one compound. The 2026 scoping review listed cardiovascular complications and insulin resistance among documented risks across its six peptides, and it named MK-677 for congestive heart failure. ^[18] The TGA names CJC-1295 as an example of an unapproved peptide product and reports receiving severe allergic reactions and systemic inflammatory response syndrome for that group of products. ^[22]

CJC-1295 and ipamorelin have the same Australian status. Each has a named entry in Schedule 4 of the Poisons Standard (prescription only), and each is listed in Appendix D clause 5, which makes possession without authority an offence. CJC-1295 is item 7 and ipamorelin item 25 in the instrument that commenced on 1 June 2026. ^[9]

The same Appendix D table also lists the classes both belong to: growth hormone releasing hormones (item 18), growth hormone releasing peptides (item 19) and growth hormone secretagogues (item 21), each "including those separately specified in Schedule4". ^[9] Our guide to peptide scheduling under Australian law explains what Schedule 4 and Appendix D mean.

Sport rules give them the same status. The WADA 2026 List, effective 1 January 2026, names CJC-1295 under S2.2.4 as a GHRH analogue and ipamorelin under S2.2.4 as a growth hormone secretagogue. Every substance in class S2 is prohibited at all times and is non-Specified. ^[10] WADA revises the List every year.

Peptides Collective sells both for laboratory research use only. CJC-1295 in 10mg vials costs A$85, and ipamorelin in 10mg vials costs A$68. Stock ships from Western Australia with tracking, and both sit in our growth hormone research peptides range.

An independent lab tests every batch before it goes on sale, for purity by HPLC and identity by mass spectrometry. Each certificate is published under the batch number printed on the vial. The CJC-1295 page, the ipamorelin page and the CJC-1295 + Ipamorelin page each link the certificate for the batch on sale, and you can search the certificate of analysis library by batch number.

Identity is the result that separates these compounds. A reading near 711.9 g/mol matches ipamorelin. For CJC-1295, a reading near 3647.2 g/mol matches the albumin-binding molecule from the published trials, and a reading near 3367.9 g/mol matches the shorter form without it. ^[1][12][7] Our guide on how to read a peptide certificate of analysis walks through the HPLC trace and the mass spectrum.

CJC-1295 and ipamorelin reach GH release through two different pituitary receptors, and they differ five-fold in mass and by days against hours in half-life. Each has a small human record of its own, and no study has compared them directly or tested them as a pair. In Australia both are Schedule 4 substances in Appendix D clause 5, and WADA prohibits both at all times. For any vial, the batch certificate's mass result shows which molecule is inside.