CJC-1295 and Ipamorelin: The GH Secretagogue Pair

What are CJC-1295 and ipamorelin?

CJC-1295 is a modified 29-residue fragment of growth hormone-releasing hormone (GHRH) that acts on the GHRH receptor of the pituitary; ipamorelin is a five-residue synthetic peptide that acts on the ghrelin receptor. Both prompt the pituitary to release growth hormone, by different routes, and neither is approved for any use anywhere.

The name CJC-1295 covers two different molecules. The version ConjuChem took into human trials carries a Drug Affinity Complex (DAC), a maleimidopropionyl group on an extra lysine that bonds to serum albumin after injection. The version in most research vials, and in every blend with ipamorelin, lacks that group and is properly called modified GRF (1-29), or CJC-1295 without DAC. Ipamorelin (NNC 26-0161) was developed by Novo Nordisk in the 1990s; its development stopped after a phase 2 trial in postoperative ileus.

CJC-1295 No DAC

Modified GRF (1-29)

29 residues, 3367.9 g/mol, GHRH receptor. Never studied in people.

CJC-1295 with DAC

Albumin-bound GHRH analog

30 residues, 3647.2 g/mol. Half-life of 5.8 to 8.1 days in healthy adults.

Ipamorelin

Ghrelin receptor agonist

5 residues, 711.9 g/mol. Half-life of about 2 hours after intravenous infusion.

How does a GHRH analog differ from a ghrelin-receptor agonist?

GHRH and its analogs bind the GHRH receptor on pituitary somatotrophs and drive both synthesis and release of growth hormone. Ghrelin and the synthetic growth hormone-releasing peptides (GHRPs) bind a separate receptor, GHS-R1a, and trigger release through a different intracellular signal. Because the two signals are independent, giving both at once produces more growth hormone than either alone.

That synergy was shown in people in 1990, with the older GHRP-6 rather than ipamorelin. In 18 healthy men, peak growth hormone after placebo and after 0.1, 0.3 and 1.0 mcg/kg of intravenous GHRP-6 was 1.2, 7.6, 16.5 and 68.7 mcg/L, and the two lower GHRP-6 doses given together with 1 mcg/kg of GHRH released more than the sum of the parts. Ipamorelin was designed later to keep the growth hormone effect of GHRP-6 while dropping its side effects. In rats and pigs it matched GHRP-6 for GH release but, unlike GHRP-6 and GHRP-2, did not raise ACTH or cortisol beyond what GHRH itself produced.

Why do the DAC and no-DAC versions have such different half-lives?

Native GHRH(1-29) is cleared in minutes, chiefly by the enzyme DPP-4. ConjuChem introduced four substitutions (D-Ala2, Gln8, Ala15, Leu27) to resist that breakdown, then added the DAC: a C-terminal lysine carrying a maleimidopropionyl group that bonds to cysteine 34 of serum albumin once the drug is in the blood. The albumin-bound conjugate was identified as the long-lasting candidate in rat studies published in 2005, and the human phase 1 trials then measured a half-life of 5.8 to 8.1 days. Without the DAC, the same 29 residues are still cleared in well under an hour. Community guides quote about 30 minutes for the no-DAC peptide against about 8 days for the DAC form, but the 30-minute figure is an inference from GHRH physiology: the no-DAC peptide has no published human pharmacokinetics.

The confusion has consequences. PubChem lists DAC and no-DAC synonyms on the same record, vendors sell both under the same four digits, and in 2010 a Norwegian doping laboratory reported on an unknown preparation submitted by police and customs: it contained a 29-residue amidated peptide whose sequence matched the product marketed as CJC-1295, which is the no-DAC molecule, not the albumin-binding drug. A weekly schedule written for the albumin-bound drug, applied to a vial of the short-acting peptide, produces a different exposure entirely.

What did the human trials of CJC-1295 report?

Two phase 1 trials, published together in 2006, are most of the human record, and both used the DAC molecule. In the single-dose study, healthy adults aged 21 to 61 received 30, 60, 125 or 250 mcg/kg subcutaneously. Mean growth hormone rose 2- to 10-fold for six days or more and IGF-1 rose 1.5- to 3-fold for 9 to 11 days; IGF-1 left the age-adjusted normal range only at 250 mcg/kg. In the repeat-dose study, 20 or 30 mcg/kg weekly or 30 or 60 mcg/kg every two weeks kept IGF-1 above baseline through day 28, and peak drug levels after the day-14 injection were 29% to 70% higher than after the first, which the authors read as accumulation. Injection-site reactions occurred in about 70% of treated subjects in the single-dose study and in every treated subject in the repeat-dose study; flushing, loose stools and headache were dose-related; no serious adverse reactions were recorded.

The third study gave healthy men aged 20 to 40 a single 60 or 90 mcg/kg dose and sampled blood every 20 minutes overnight, before and one week after. A week later, trough growth hormone was 7.5 times higher, mean GH was up 46% and IGF-1 up 45%, while the number and size of GH pulses had not changed. The phase 2 trial in HIV-associated visceral obesity (NCT00267527) was terminated in 2006 without posting results, ConjuChem stopped development, and the drug was never approved. A 2026 narrative review grades the evidence as phase 1 pharmacokinetics and pharmacodynamics in healthy adults, with no controlled efficacy or long-term safety data.

What did the human studies of ipamorelin report?

Ipamorelin has two human studies and both used intravenous dosing. In the 1999 pharmacokinetic study, 40 healthy men received single 15-minute infusions of 4.21 to 140.45 nmol/kg, roughly 3 to 100 mcg/kg. Kinetics were dose-proportional with a terminal half-life of about 2 hours, and every dose produced a single growth hormone pulse that peaked at about 40 minutes and then faded to baseline. The growth hormone response varied between people far more than the drug concentrations did.

The 2014 phase 2 trial enrolled 117 adults after bowel resection and gave 0.03 mg/kg intravenously twice daily from the first postoperative day for up to seven days. Median time to the first tolerated meal was 25.3 hours on ipamorelin against 32.6 hours on placebo, a difference that did not reach significance, and no secondary endpoint separated from placebo either. Adverse events were slightly fewer than with placebo (87.5% versus 94.8%). That trial is the only controlled multi-day exposure of ipamorelin in humans. Nightly subcutaneous dosing, the pattern every community protocol describes, has never been studied.

Why are CJC-1295 and ipamorelin sold together?

The pairing follows the 1990 synergy logic: a GHRH analog to raise the ceiling of the pulse and a GHRP to fire it. Community guides add a second argument, that roughly 100 mcg of either peptide saturates its pituitary receptors for one pulse, so they add injections through the day rather than raising a single dose. Blend vials fix the ratio at 1:1, sold as 5 mg plus 5 mg or 10 mg plus 10 mg, so a draw that delivers 200 mcg of ipamorelin delivers 200 mcg of CJC-1295 No DAC with it. The blend page tabulates the vendor and clinic protocols: typically 100 to 300 mcg of each peptide, once to three times daily on an empty stomach or at bedtime, for 8 to 16 weeks.

Several of those sources state the limitation themselves: a 2026 planning guide for the blend says no published human trial has tested it at these amounts and that safety beyond 90 days has not been studied, and a practitioner protocol built around IGF-1 and glucose monitoring says no randomized trial has tested the pair.

Has the combination itself been studied?

No. No published trial, observational study or registered study has given CJC-1295 and ipamorelin together to people. The human synergy data are single intravenous boluses of GHRH(1-44) with GHRP-6 measured over about an hour: a different GHRH, a different GHRP and a different route. Every human CJC-1295 trial used the DAC molecule that blend vials do not contain, and every human ipamorelin study was intravenous. What the two do together, nightly and subcutaneously for months, is unmeasured.

What amounts do the sources report?

The only human doses are weight-based and belong to the DAC molecule: 30 to 90 mcg/kg across the three studies, which is about 2 to 6 mg for a 70 kg adult, with 30 and 60 mcg/kg described as the best tolerated. Forum and vendor schedules for the DAC form run 1 to 2 mg a week in 8 to 16 week cycles, at or below the trial range per kilogram but continued for far longer than the two weeks any trial dosed. For the no-DAC peptide and for ipamorelin, every figure is community or clinic practice: 100 mcg of each to start, titrated to 200 to 300 mcg, with ipamorelin guides stating that larger amounts add little growth hormone.

The arithmetic that connects those figures to a syringe is the same as for any vial: a 5 mg plus 5 mg blend made up with 3 mL holds 3.33 mg/mL in total, so one unit on a U-100 syringe carries about 33 mcg of each peptide. The calculator does that conversion for any mass and volume, and the reconstitution guide shows the working. These are measurement examples from the sources, not amounts to use.

What this guide does not establish

This article does not establish that CJC-1295 or ipamorelin is safe, effective or appropriate for anyone, and it cannot, because the human record is two phase 1 trials of a different CJC-1295 molecule and two intravenous studies of ipamorelin. Nothing here is a dose. The full protocol tables, with each source and year, are on the compound pages for CJC-1295 No DAC, CJC-1295 with DAC and ipamorelin, and the wider growth hormone secretagogue research is covered in the muscle and recovery guide.