CJC-1295 and Ipamorelin: What the Evidence Shows
CJC-1295 and ipamorelin are sold as a pair, on the idea that two routes to growth hormone release beat one. Each has been in real human studies, though not many. The pair has never been tested together in a published controlled human trial. Here is what exists and what doesn't.
- CJC-1295 is a modified GHRH(1-29) analog. The 'DAC' version binds to albumin and had a half-life of 5.8–8.1 days in healthy adults. 'No-DAC' material (often sold as mod GRF 1-29) lacks that group and has no published human pharmacokinetic study.
- Ipamorelin is a pentapeptide ghrelin-receptor agonist. In healthy men it had a terminal half-life of about 2 hours and caused a single GH pulse peaking around 40 minutes after infusion.
- Human data: phase 1 studies of CJC-1295 with DAC in healthy adults, and a PK study plus a phase 2 trial of IV ipamorelin for postoperative ileus. The ileus trial did not beat placebo. The combination has no controlled human trial.
- Neither is FDA-approved. FDA lists serious adverse events for both on its compounding safety page. Ipamorelin acetate remains in category 2 under the 503B policy. Both are on WADA's list of substances prohibited at all times.
The short version is that each peptide has a small amount of human data, and the combination people actually use has none. CJC-1295 with DAC raised growth hormone (GH) and IGF-1 for days after a single injection in two placebo-controlled phase 1 trials in healthy adults1. Ipamorelin produced a short, single GH pulse at every dose tested in healthy men5. Its one published efficacy trial, in postoperative ileus, found no significant benefit over placebo6. A 2026 review in Frontiers in Endocrinology describes pairing ipamorelin with no-DAC CJC-1295 as 'largely driven by anecdotal rationale', with controlled evidence for synergy or body-composition benefit 'limited'7. Neither compound is FDA-approved, and both appear on FDA's list of compounding substances with safety concerns8. This guide covers the mechanism, the DAC question, each human study, the safety signals and the regulatory position. Compound background is on our CJC-1295 and ipamorelin pages.
Two receptors, one hormone: the mechanism
The pituitary releases GH in response to two separate signals. Growth hormone-releasing hormone (GHRH) acts on the GHRH receptor. Ghrelin and the drugs that mimic it act on the growth hormone secretagogue receptor. CJC-1295 works on the first pathway. It was developed as a modified version of human GRF(1-29), the active 29-amino-acid fragment of GHRH, and its albumin conjugates showed improved stability against dipeptidyl peptidase-IV, an enzyme that degrades GRF3. Ipamorelin works on the second. Its developers at Novo Nordisk showed in 1998 that its GH release was blocked by GHRP antagonists, not GHRH antagonists, so it acts through the GHRP (ghrelin) receptor like the older GHRP-64.
Ipamorelin's selling point from the start was selectivity. In conscious swine it released GH with potency similar to GHRP-6, but unlike GHRP-6 and GHRP-2 it did not raise ACTH or cortisol above the levels seen with GHRH, even at doses more than 200 times its ED50. None of the secretagogues tested changed FSH, LH, prolactin or TSH4. The authors called it 'the first GHRP-receptor agonist with a selectivity for GH release similar to that displayed by GHRH'4. Those selectivity findings came from swine, not from people.
The reasoning behind stacking the two follows from this: two receptors, two signals, possibly a bigger pulse. The 2026 review notes that ipamorelin is frequently combined with CJC-1295, 'typically the non-DAC form', to amplify GH release, and that controlled clinical evidence for synergy or meaningful outcomes in healthy people 'remains limited'7. We found no published controlled human trial of the combination.
DAC vs no-DAC: two different drugs under one name
'CJC-1295' is used for two molecules with very different behavior. The original compound, described in 2005, is a tetrasubstituted GRF(1-29) with an extra lysine carrying a maleimido reactive group at the C-terminus3. That group is the 'Drug Affinity Complex' (DAC). After injection it binds covalently to the free thiol on serum albumin. In rats, a CJC-1295–albumin complex was still in circulation after 24 hours and the compound was detectable in plasma beyond 72 hours3. In humans, the half-life was 5.8–8.1 days1.
The version sold as 'CJC-1295 without DAC' or 'mod GRF 1-29' is the modified peptide without that reactive group. It can't hitch a ride on albumin, so it is expected to clear far faster. The 2026 review states that no controlled clinical studies have directly evaluated it in humans. It lists its human half-life as not reported, and says claims about its effects 'derive largely from extrapolation from related compounds'7. Short half-life figures quoted online for the no-DAC form don't come from a published human pharmacokinetic study that we could find.
| CJC-1295 with DAC | CJC-1295 without DAC (mod GRF 1-29) | Ipamorelin | |
|---|---|---|---|
| Target | GHRH receptor3 | GHRH receptor | GHRP / ghrelin receptor4 |
| Structure | Modified GRF(1-29) + maleimido lysine that binds albumin3 | Modified GRF(1-29) without the albumin-binding group | Pentapeptide Aib-His-D-2-Nal-D-Phe-Lys-NH24 |
| Human half-life | 5.8–8.1 days1 | Not reported in human studies7 | About 2 hours (IV)5 |
| GH pattern in humans | Raised for days; pulses preserved, trough GH up 7.5-fold1,2 | No controlled human data7 | Single pulse, peak at 0.67 h5 |
| Published human studies | Two phase 1 trials in healthy adults; one pulsatility study1,2 | None controlled7 | One PK/PD study; one phase 2 trial (ileus)5,6 |
| FDA status | Not approved; listed as nominated for compounding but withdrawn8 | Not approved | Not approved; category 2 under 503B since Sept 29, 20238 |
The practical difference is the dosing interval. A peptide with a week-long half-life builds up with repeated doses, and Teichman and colleagues saw 'evidence of a cumulative effect' with IGF-1 above baseline for up to 28 days after multiple doses1. Our half-life guide explains how that accumulation works.
What the human studies of CJC-1295 found
Teichman et al., 2006: the phase 1 trials
The main human paper reports two randomized, placebo-controlled, double-blind, ascending-dose trials, lasting 28 and 49 days, in healthy adults aged 21–611. The first gave single subcutaneous doses at four levels. The second gave two or three weekly or every-other-week doses1. After one injection, mean GH rose 2- to 10-fold, dose-dependently, for 6 days or more, and mean IGF-1 rose 1.5- to 3-fold for 9–11 days1. No serious adverse reactions were reported. The authors described the drug as safe and relatively well tolerated, 'particularly at doses of 30 or 60 microg/kg'1.
Ionescu and Frohman, 2006: is the GH still pulsatile?
A constant GHRH signal might have been expected to flatten GH's natural pulses. To test this, healthy men aged 20–40 had blood drawn every 20 minutes overnight before and one week after a single 60 or 90 µg/kg injection2. Pulse frequency and size did not change. Trough GH rose 7.5-fold, mean GH rose 46% and IGF-1 rose 45%, with no difference between the two doses2. A separate analysis of serum from 11 healthy young men, taken before and one week after a CJC-1295 injection, found changes in several blood proteins after treatment, proposed as possible markers of GH action12.
The trial that stopped
Development went on into a phase 2 trial in 192 people with HIV-associated visceral obesity. In July 2006, the developer, ConjuChem, halted it after a participant died at a site in Argentina10. At the time of the report, the cause and any link to CJC-1295 were still under investigation10. We found no published efficacy results from that program, and CJC-1295 was never approved. The GHRH analog that did reach the market is tesamorelin (EGRIFTA), approved to reduce excess abdominal fat in adults with HIV and lipodystrophy. Its label requires periodic IGF-1 monitoring11; see our tesamorelin page.
What the human studies of ipamorelin found
The human pharmacology comes from a dose-escalation study in healthy men. Eight subjects at each of five infusion rates received ipamorelin intravenously over 15 minutes5. Its pharmacokinetics were dose-proportional, with a terminal half-life of 2 hours. Each dose produced a single episode of GH release, peaking at 0.67 hours and declining to negligible levels, at every dose tested5. This profile of a short half-life and one pulse per dose is why people dose ipamorelin more than once a day.
Clinical development then moved to gut motility rather than GH. In a multicenter, double-blind, placebo-controlled phase 2 trial, adults recovering from bowel resection received IV ipamorelin 0.03 mg/kg or placebo twice daily for up to 7 days6. Of 117 patients enrolled, 114 were analyzed. Median time to the first tolerated solid meal was 25.3 hours with ipamorelin and 32.6 hours with placebo (p = 0.15). The authors reported no significant differences on the key or secondary efficacy measures6. Adverse events were common in both groups (87.5% on ipamorelin, 94.8% on placebo), and the drug was described as well tolerated6.
Safety signals
The published trials themselves report few problems. Teichman's trials had no serious adverse reactions1, and the ileus trial described ipamorelin as well tolerated6. FDA's compounding safety page, reviewed for nominations of these substances, goes further:
| Source | CJC-1295 | Ipamorelin acetate |
|---|---|---|
| FDA category 2 page (current as of 04/22/2026) | 'FDA has identified serious adverse events associated with CJC-1295 including increased heart rate and systemic vasodilatory reaction. Available clinical data are limited.'8 | 'A study published in literature identified serious adverse events including death when ipamorelin was administered intravenously for improving gastric motility.' FDA also says it lacks safety information for other injectable routes8 |
| FDA, both compounds | Possible immunogenicity; complexity of peptide-related impurities and characterization8 | Possible immunogenicity from aggregation or impurities; unnatural amino acids complicate characterization8 |
| 2026 clinical review (GH-axis peptides as a class) | Reported problems include hormonal and metabolic disturbances, fluid retention, muscle and joint pain and injection-site reactions; chronic GH–IGF-1 stimulation is a theoretical mitogenic concern7 | Same class-level concerns7 |
Product quality is a separate risk from the molecule. Norwegian police and customs submitted an unidentified preparation for analysis, and a 2010 lab report identified it as CJC-1295. It is one early example of these peptides moving through illicit channels before their clinical development was finished13. Our guide to peptide safety covers what untested supply means for purity and dose.
Regulatory status in 2026
FDA approval: neither CJC-1295 nor ipamorelin is approved for any use. The 2026 review notes that neither CJC-1295 variant is approved by major regulators7.
Compounding: FDA's page on bulk substances that may present significant safety risks (content current as of April 22, 2026) has two lists8. Ipamorelin acetate is on the active category 2 list under the 503B (outsourcing facility) policy, added September 29, 2023. It also appears on the list of substances 'nominated but withdrawn', with the note that it remains in category 2 under 503B. CJC-1295 appears only on the withdrawn list, which FDA describes as substances 'previously in category 2 of the interim policies' whose nominations 'were withdrawn by the nominators'8. A withdrawn nomination is not an approval. FDA's page doesn't describe either substance as cleared for compounding. The July 23–24, 2026 meeting of FDA's Pharmacy Compounding Advisory Committee reviewed BPC-157, KPV, TB-500 and MOTS-c, then emideltide, Semax and epitalon, for the 503A bulks list. CJC-1295 and ipamorelin were not on the agenda9.
Sport: the 2026 WADA Prohibited List names CJC-1295 among GHRH analogues and ipamorelin among GH secretagogues in section S2, which is prohibited at all times, in and out of competition14.
What this means in practice
The strongest honest statement is limited. CJC-1295 with DAC reliably raises GH and IGF-1 for days in healthy adults, and ipamorelin reliably triggers a short GH pulse. Whether either, or both together, improves anything a user cares about has not been shown in a controlled human trial. Nor has long-term safety at repeated doses. The dosing protocols circulating online, such as the forum patterns summarized in the 2026 review7, are not trial doses. We don't give doses here.
If you already use either compound and track it, the arithmetic of reconstitution is covered by our CJC-1295 calculator and ipamorelin calculator, which convert a vial and water volume into syringe units. Our guides on bacteriostatic water and peptide storage explain why no fridge-life figure for these vials is backed by testing. Because a rising IGF-1 is the one measurable effect both compounds share, any use belongs under a clinician who can order and interpret that blood test. This guide is educational and not medical advice.
FAQ
References
Primary sources — PubMed / NEJM / The Lancet.
- Teichman SL, Neale A, Lawrence B, Gagnon C, Castaigne JP, Frohman LA. 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. J Clin Endocrinol Metab. 2006;91(3):799-805. https://pubmed.ncbi.nlm.nih.gov/16352683/
- Ionescu M, Frohman LA. Pulsatile secretion of growth hormone (GH) persists during continuous stimulation by CJC-1295, a long-acting GH-releasing hormone analog. J Clin Endocrinol Metab. 2006;91(12):4792-4797. https://pubmed.ncbi.nlm.nih.gov/17018654/
- Jetté L, Léger R, Thibaudeau K, et al. 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. 2005;146(7):3052-3058. https://pubmed.ncbi.nlm.nih.gov/15817669/
- Raun K, Hansen BS, Johansen NL, et al. Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol. 1998;139(5):552-561. https://pubmed.ncbi.nlm.nih.gov/9849822/
- Gobburu JV, Agersø H, Jusko WJ, Ynddal L. Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers. Pharm Res. 1999;16(9):1412-1416. https://pubmed.ncbi.nlm.nih.gov/10496658/
- Beck DE, Sweeney WB, McCarter MD; Ipamorelin 201 Study Group. Prospective, randomized, controlled, proof-of-concept study of the ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients. Int J Colorectal Dis. 2014;29(12):1527-1534. https://pubmed.ncbi.nlm.nih.gov/25331030/
- Dominikowski A, Rękoś Z, Olejarz M, Szczepanek-Parulska E, Domin R, Ruchała M. The emerging landscape of performance-enhancing peptides modulating GH-IGF1 axis: bridging the gap between clinical evidence and patient self-administration. Front Endocrinol (Lausanne). 2026;17:1822475. https://pmc.ncbi.nlm.nih.gov/articles/PMC13322892/
- U.S. FDA. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (content current as of 04/22/2026). https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks
- U.S. FDA. July 23-24, 2026: Meeting of the Pharmacy Compounding Advisory Committee. https://www.fda.gov/advisory-committees/advisory-committee-calendar/july-23-24-2026-meeting-pharmacy-compounding-advisory-committee-07232026
- Bernard EJ. Lipodystrophy study halted after patient death. aidsmap. 31 July 2006. https://www.aidsmap.com/news/jul-2006/lipodystrophy-study-halted-after-patient-death
- DailyMed (U.S. National Library of Medicine). EGRIFTA WR (tesamorelin) for injection — Prescribing Information, Theratechnologies Inc. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=839334d3-8c1d-4c26-9036-2ab524a6ea75
- Sackmann-Sala L, Ding J, Frohman LA, Kopchick JJ. Activation of the GH/IGF-1 axis by CJC-1295, a long-acting GHRH analog, results in serum protein profile changes in normal adult subjects. Growth Horm IGF Res. 2009;19(6):471-477. https://pmc.ncbi.nlm.nih.gov/articles/PMC2787983/
- Henninge J, Pepaj M, Hullstein I, Hemmersbach P. Identification of CJC-1295, a growth-hormone-releasing peptide, in an unknown pharmaceutical preparation. Drug Test Anal. 2010;2(11-12):647-650. https://pubmed.ncbi.nlm.nih.gov/21204297/
- World Anti-Doping Agency. World Anti-Doping Code International Standard: Prohibited List 2026 (S2.2.4). https://www.wada-ama.org/sites/default/files/2025-09/2026list_en_final_clean_september_2025.pdf