Ipamorelin + CJC-1295

What Ipamorelin + CJC-1295 is

Ipamorelin and the No DAC form of CJC-1295 are two separate lab-made peptides that are often studied as a pair. Nobody has tested the pair itself in a proper trial. As of April 2026, no peer-reviewed randomized controlled trial of this exact combination has been completed. The evidence comes in two parts. One is data on each compound given alone. The other is a wider set of studies on similar pairs, which scientists reason from. The FDA, the EMA and the MHRA have not approved the combination as a treatment.

A peptide is a short chain of amino acids, the building blocks of protein. Both of these are growth hormone secretagogues, compounds that prompt the pituitary gland to let out growth hormone (GH). The pituitary is a gland at the base of the brain. Animal and lab research uses the two together to study GH release in pulses.

They work on two different receptors in the GH system. A receptor is a spot on a cell where a signal attaches.

• Ipamorelin is a chain of five amino acids. It is a selective agonist of GHSR-1a, meaning it switches that receptor on. GHSR-1a is the same receptor used by ghrelin, a peptide the body makes itself [1], [3].
• CJC-1295 No DAC, also called modified GRF 1-29, is a 29-amino-acid analog of GHRH (growth hormone-releasing hormone). An analog is a changed copy. GHRH is the body’s own signal for GH release. The analog attaches to the GHRH receptor in the pituitary [13].

The case for pairing them rests on a classic finding. In several kinds of mammal, turning on both pathways at once released more GH than adding up the two separate effects would predict [4], [5], [10]. Scientists call that supra-additive.

Each partner was picked for a reason.

• Ipamorelin has an unusually clean profile. At standard research doses it releases GH strongly and barely moves ACTH, cortisol or prolactin [1]. Cortisol is a stress hormone, ACTH is the pituitary signal that calls for it, and prolactin is a milk hormone.
• CJC-1295 No DAC keeps its action at the GHRH receptor. The DAC version forms a covalent bond with albumin, a protein in the blood, and that makes it last much longer [8]. The No DAC version has no such linker. That gives it a shorter half-life, which suits models of pulsed release better. Half-life is the time it takes for half of a compound to leave the blood.

How much research there is

No trial of the pair. Some data on each compound alone, and 30 years of work on similar pairs.

Question	Answer
Randomized trials of this exact pair	None in print (April 2026)
Ipamorelin alone	Drug action mapped in animals and in the lab. Rodent results for bone and for GH release [1], [2]
CJC-1295 alone	Phase I data in people for the DAC version. Rodent data for both versions [7], [8], [9]
Similar pairs of a GHRP with GHRH	Strong across three decades. Studies in rodents, dogs and humans using several peptide pairs [4], [10], [11], [12], [16]
What cannot be carried over	Reasoning from related pairs is about how things work, not about amounts. There are no figures for how the body handles this pair or responds to it

How it might work

The simplest way to follow the idea is to take the two receptor systems one at a time. After that comes the question of how they meet at the somatotroph, the pituitary cell that makes GH. What follows was worked out mainly in animals, in pituitary cells studied on their own, and in human volunteer studies of GHRPs and GHRH analogs.

Two compounds, two receptors

Ipamorelin, a GHRP. GHRP stands for growth hormone-releasing peptide. Ipamorelin (Aib-His-D-2-Nal-D-Phe-Lys-NH2) was first described in 1998 by a Novo Nordisk team under Raun [1]. It attaches to GHSR-1a, a G-protein-coupled receptor, which is a common type of cell switch. A year later, Kojima and colleagues identified ghrelin as that receptor’s natural partner [3].

It acts in two places.

• On somatotrophs, a switched-on GHSR-1a links mostly to a route called Gq/phospholipase C. Calcium is freed inside the cell, and that pushes GH out.
• In the hypothalamus, a part of the brain, it also lowers somatostatin tone. Somatostatin is the hormone that holds GH back and is the main natural brake. Easing it boosts GH release indirectly [4], [11].

CJC-1295 No DAC, a GHRH analog. The working part of human GHRH is its N-terminal 1-29 piece, the front end of the chain. CJC-1295 No DAC is a copy of that piece with four amino acids swapped: D-Ala2, Gln8, Ala15 and Leu27. The swaps help it resist enzymes and last longer in plasma than natural GHRH. It still binds to the GHRH receptor in the pituitary.

That receptor belongs to class B of the G-protein-coupled receptors. It links mainly to Gs/adenylyl cyclase. That raises cAMP, a messenger inside the cell, and turns on an enzyme called protein kinase A (PKA). The outcome is that the cell both makes and releases more GH [13].

The two receptors do not hold the same rank in the GH system. GHRH is the main “go” signal. It drives the growth of somatotrophs and the reading of the GH gene [6]. The GHRP/ghrelin system mostly turns up the GHRH signal that is already there, and it works against somatostatin [13], [14].

Two signals in one cell

Given together, the two compounds reach the somatotroph through two separate chains of second messengers, the relay signals inside a cell.

• GHRH receptor signals travel by the cAMP/PKA route.
• GHSR-1a signals travel by the calcium/PLC route.

Both end at the machinery that empties the cell’s GH packets. Their earlier steps mostly do not overlap. This side-by-side action is the molecular reason GH release is supra-additive, an effect that has been recorded again and again when a GHRP and a GHRH compound are given together [4], [5], [10], [12].

Bowers and colleagues showed the core effect as early as 1990. They gave healthy men GHRP-6 with GHRH, each at less than a full dose. The GH peaks were far higher than the two single responses added together [4].

Work in the 1990s and the early 2000s repeated the effect in several species. It held for other GHRP-type peptides too. These were hexarelin [10], ghrelin itself [10], [11], and newer GHSR agonists that came later. Thorner and colleagues have reviewed it at length [12].

Somatostatin adds a second layer. Somatostatin tone from the hypothalamus holds GH back in a rhythm, and that rhythm shapes the normal pulses. Switching on the GHRP/ghrelin receptor has been shown to do two things. It weakens the blocking action of somatostatin at the pituitary. It also cuts how much somatostatin the hypothalamus lets out [11], [13]. When a GHRH signal is present, the result is a GH pulse that is bigger and lasts longer than GHRH can produce alone.

Keeping the pulses

The body lets out GH in separate bursts. The biggest ones come in deep, slow-wave sleep. The bursts are not a side detail. How tissues respond to GH depends on how often the pulses come and how tall they are, as much as on the total GH made in a day. Two such responses are the liver’s making of IGF-1 (insulin-like growth factor 1) and gene activity that differs by sex [8], [14].

Pulses arise from a back-and-forth between two signals from the hypothalamus. GHRH drives the peaks and somatostatin sets the dips [17]. Ghrelin acts as a booster whose effect depends on the setting [13], [14].

GH can also be raised without a break. Injected recombinant (lab-made) GH does that. So does the albumin-bound DAC version of CJC-1295.

• Teichman and colleagues (2006) showed that long-acting CJC-1295 DAC kept GH raised in healthy adults [7].
• Sackmann-Sala and colleagues found that such lasting activation changed the mix of proteins in blood serum, in a way that fits a GH/IGF-1 axis that stays engaged [9].

The thinking behind the ipamorelin and No DAC pair is different. Turning on both natural input pathways may come closer to the body’s own pulsed release. The No DAC version has a shorter half-life, and the hypothesis is that it keeps the pattern of peaks and dips. Ipamorelin would add separate spikes of release, much as the body’s ghrelin makes pulses taller [11], [14].

What the studies found

As of April 2026, no peer-reviewed trial had directly tested the two peptides together. The evidence has to be pieced together from three sets of papers:

1. Studies of each peptide alone.
2. Wider studies that paired a GHRP with GHRH, using related compounds.
3. Reviews and mechanism papers on pulsed GH release.

Each compound alone

• Ipamorelin, first report. Raun and colleagues tested ipamorelin in cultured pituitary cells and in live animals. It released GH in both, and more so at higher doses. It was about as strong as GHRP-6 but far more selective. In pigs, GHRP-6 and GHRP-2 raised ACTH and cortisol. Ipamorelin did not raise them significantly, even at doses far above those that released GH. None of the three changed prolactin. That made ipamorelin the first GHSR agonist that was truly selective [1].
• Bone. Svensson and colleagues dosed adult female rats with ipamorelin. A DXA scan showed higher bone mineral content. The gain came from bigger bones, not from a change in density by volume [2]. This early paper tied the compound to effects on bone and muscle tissue that go past short-term GH release.
• CJC-1295 DAC in people. Teichman and colleagues ran a randomized, placebo-controlled phase I study of the long-acting DAC version, the one that binds albumin. In healthy adults, mean GH and IGF-1 rose with dose. After one injection, GH stayed raised for 6 days or more and IGF-1 for 9 to 11 days. After two or three doses, IGF-1 stayed above baseline for up to 28 days [7]. No other human drug data set for the CJC-1295 family is cited as often.
• CJC-1295 in mice without GHRH. Alba and colleagues gave CJC-1295 once a day to GHRH-knockout mice. Growth and body makeup returned to normal. So the analog can stand in for the body’s own GHRH in a controlled model of GHRH shortage [8].
• Effects further down the chain. Sackmann-Sala and colleagues measured serum proteins in adults receiving CJC-1295, using quantitative proteomics, a survey of many proteins at once. The changes fit a GH/IGF-1 axis kept engaged over time, not lone spikes of GH [9].

Related pairs given together

This exact pair has never been through a peer-reviewed controlled trial. A large body of work on close relatives, each a GHRP given with GHRH, shapes the case for it.

• The classic Bowers studies. In healthy men, GHRP-6 plus GHRH at less than full doses gave GH responses that were significantly bigger than both single responses added up. That set up two-receptor synergy as a drug effect that can be repeated [4]. A companion paper in rats showed that the GHRP receptor system was neither a GHRH system nor an opiate one [5]. It pointed ahead to the later discovery of GHSR-1a.
• Hexarelin with GHRH, by age. Arvat and colleagues gave hexarelin together with GHRH and recorded a synergistic rise in GH. It was greater in young adults than in older ones. That suggests somatostatin tone, which shifts with age, changes how big the effect is [10].
• Ghrelin with GHRH in people. After ghrelin was discovered, Popovic and colleagues showed that it acts on GH release chiefly at the hypothalamus. Ghrelin and GHRH together released the most GH, and the results pointed to lower somatostatin as one way it works [11]. This matters for the pair in this guide because ipamorelin is a lab-made stand-in for ghrelin at GHSR-1a.

Pulses compared with steady release, and reviews

• Pulsed or constant. Veldhuis and colleagues have argued many times that the pulsed mode of GH release decides how tissues respond, not just the summed exposure over 24 hours. Their examples include the timing of IGF-1 from the liver and effects on body makeup [14]. This is the theory behind favoring a pair that keeps pulses, like the one in this guide, over options that give a lasting rise (CJC-1295 DAC alone, or recombinant GH).
• Reviews of GHRH and GHRP as treatments. In 1997 Thorner and colleagues reviewed both as possible medicines. They concluded that giving them together was the most promising way to restore natural GH output in disease and in aging, as long as the somatotrophs can still do their job [12]. Walker (2006) summed up the clinical case for GHRH-based approaches over injected GH in GH shortage that starts in adult life [15].
• Secretagogues head to head. In 2001 Arvat and colleagues ran ghrelin, hexarelin and GHRH against each other in humans. The GHS-type peptides released more GH than GHRH did alone. Giving them together gave the biggest responses of all [16].

Why the two are paired

The case for synergy has four linked parts. Each part has its own body of animal and lab research behind it. Fitting them together into this exact pair is still a theory.

More than the sum

GHSR-1a and the GHRH receptor sit on one cell type, the somatotroph of the pituitary. They use second-messenger systems that do not overlap. Turning both on at once therefore gives a bigger GH response than either signal alone. In most reported experiments, it also beats the plain sum of the two. That is the test that separates true drug synergy from simple adding [4], [5], [12], [16].

The effect repeats in rodent, dog and human samples, and with several GHRP-type compounds. This suggests it comes from how the receptors work and not from any one peptide.

Lifting the somatostatin brake

A key piece of the synergy is what GHRP/ghrelin-receptor agonists do to somatostatin in the hypothalamus. Popovic and colleagues showed that ghrelin acts on GH release mainly there, by lowering somatostatin output [11]. Somatostatin is a brake on GH release from the pituitary. With the brake off, a pulse driven by GHRH can reach its full height.

Ipamorelin is a selective GHSR-1a agonist, so it is expected to ease the brake in the same way. It should do so without the changes in ACTH, cortisol and prolactin that muddied results with earlier GHRP-type peptides [1], [4].

Half-lives that match

In animal and lab models, the No DAC peptide has a half-life in plasma of somewhere between about 30 minutes and a few hours. That is long enough to give a lasting GHRH signal and draw the typical somatotroph response. It is short enough that its hold on the receptor tapers off and does not become flat, nonstop activation.

This is the main reason scientists use No DAC and not DAC in the pair. The DAC version bonds covalently to serum albumin and keeps the GHRH receptor engaged for days. GH and IGF-1 then stay raised for days as well [7], [9].

Ipamorelin also has a fairly short half-life. So the two fit together in plans meant to give separate GH pulses and not a long rise.

Copying natural pulses

The broad aim of the pair, in theory, is to match the body’s own pattern of GH release more closely than either compound can alone. Natural GH output comes from three things acting together: GHRH peaks, dips driven by somatostatin, and a boost from ghrelin.

A GHRH analog (the No DAC peptide) plus ipamorelin, a GHSR-1a agonist, engages both “go” arms of this control loop together. The hypothesis is that, with the right timing, the pair gives a pulse taller than either compound gives alone. Because both clear quickly, the pattern of peaks and dips would stay in place. Veldhuis and colleagues have named that pattern as relevant to IGF-1 signals further down the chain and to GH effects in tissue [14].

What is shown and what is assumed

It helps to keep direct findings apart from reasoning.

Shown directly in peer-reviewed papers:

• Synergy between a GHRP and GHRH is a strong, repeatable effect. It holds across many pairs of peptides, many species and several age groups [4], [10], [11], [16].
• Ipamorelin releases GH and is selective for GHSR-1a [1].
• CJC-1295, in both versions, switches on the human GH/IGF-1 axis [7], [9].

Reasoned, not shown:

• The actual size of the GH response to this pair in humans.
• Whether it has any edge over other pairings of a GHRP with GHRH.
• How far kept pulses lead to different effects in target tissues.

No head-to-head trial large enough to answer these has been published.

Legal status in the US

• Not FDA approved. Neither peptide alone, nor the pair, is approved as a treatment by the FDA. The same is true of the EMA in Europe and the MHRA in the UK.
• Banned in sport. Both fall in the World Anti-Doping Agency (WADA) category S2, which covers peptide hormones, growth factors, related substances and mimetics. They are banned both in competition and out of it.
• Research use. For laboratory research use only, not for human use.

Limits of the research

1. Reasoning from related pairs. Most of the case for synergy comes from studies that gave GHRH with GHRP-6, with hexarelin or with ghrelin. Carrying it over to ipamorelin and the No DAC peptide makes sense in terms of mechanism. No controlled trial has formally shown it.
2. No finished human trial of the pair. Peer-reviewed randomized trial data do not back any claim about how well this pair works, how safe it is, or whether it beats one compound alone.
3. Assumptions about half-life. The reason for choosing these two analogs assumes short to medium half-lives that keep pulses intact. The published figures on how the body handles them come mainly from rodents and non-human primates. For both peptides in this pair, human data are limited.
4. Feedback in the GH system. When the GH/IGF-1 axis is switched on for long or again and again, IGF-1 and somatostatin feed back to damp it. Published combination studies have not properly shown how long pulses stay intact under repeated dosing.
5. Purity and handling. Results in peptide research are sensitive to purity, to how the peptide is mixed and stored, and to how it is given. Repeatable results depend on HPLC-verified material with a Certificate of Analysis, and on following published storage guidelines.
6. Publication bias. Studies that found nothing may be underreported, as in much GHRP and GHRH research. The run of positive reports on synergy should be read with that in mind.

Similar pairs release more growth hormone together than apart. Whether this pair does the same in people has not been tested.

References

Selected peer-reviewed references. Ordered thematically: ipamorelin, ghrelin/GHSR, GHRP + GHRH synergy, CJC-1295, and pulsatile physiology.

1. 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.0.1390552. PMID: 9849822
2. Svensson J, Lall S, Dickson SL, et al. (2000). The GH secretagogues ipamorelin and GH-releasing peptide-6 increase bone mineral content in adult female rats. Journal of Endocrinology, 165(3), 569–577. DOI: 10.1677/joe.0.1650569. PMID: 10828840
3. Kojima M, Hosoda H, Date Y, Nakazato M, Matsuo H, Kangawa K. (1999). Ghrelin is a growth-hormone-releasing acylated peptide from stomach. Nature, 402(6762), 656–660. DOI: 10.1038/45230. PMID: 10604470
4. 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 and Metabolism, 70(4), 975–982. PMID: 2108187
5. Bowers CY, Sartor AO, Reynolds GA, Badger TM. (1991). On the actions of the growth hormone-releasing hexapeptide, GHRP. Endocrinology, 128(4), 2027–2035. DOI: 10.1210/endo-128-4-2027. PMID: 2004615
6. Frohman LA, Kineman RD. (2002). Growth hormone-releasing hormone and pituitary development, hyperplasia and tumorigenesis. Trends in Endocrinology and Metabolism, 13(7), 299–303. PMID: 12163232
7. 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 and Metabolism, 91(3), 799–805. DOI: 10.1210/jc.2005-1536. PMID: 16352683
8. Alba M, Fintini D, Sagazio A, Lawrence B, Castaigne JP, Frohman LA, Salvatori R. (2006). Once-daily administration of CJC-1295, a long-acting growth hormone-releasing hormone (GHRH) analog, normalizes growth in the GHRH knockout mouse. American Journal of Physiology – Endocrinology and Metabolism, 291(6), E1290–E1294. DOI: 10.1152/ajpendo.00201.2006. PMID: 16822960
9. Sackmann-Sala L, Ding J, Frohman LA, Kopchick JJ. (2009). 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 Hormone & IGF Research, 19(6), 471–477. DOI: 10.1016/j.ghir.2009.03.001. PMID: 19386527
10. Arvat E, Ceda GP, Di Vito L, et al. (1998). Age-related variations in the neuroendocrine control, more than the endogenous tone, of growth hormone secretion in man. Pituitary, 1(1), 51–58. PMID: 11081183
11. Popovic V, Miljic D, Micic D, Damjanovic S, Arvat E, Ghigo E, Dieguez C, Casanueva FF. (2003). Ghrelin main action on the regulation of growth hormone release is exerted at hypothalamic level. Journal of Clinical Endocrinology and Metabolism, 88(7), 3450–3453. DOI: 10.1210/jc.2003-030211. PMID: 12843202
12. Thorner MO, Chapman IM, Gaylinn BD, Pezzoli SS, Hartman ML. (1997). Growth hormone-releasing hormone and growth hormone-releasing peptide as therapeutic agents to enhance growth hormone secretion in disease and aging. Recent Progress in Hormone Research, 52, 215–244. PMID: 9238854
13. Frohman LA, Kineman RD, Kamegai J, et al. (2000). Secretagogues and the somatotrope: signaling and proliferation. Recent Progress in Hormone Research, 55, 269–290. PMID: 11036941
14. Veldhuis JD, Anderson SM, Shah N, Bray M, Vick T, Gentili A, Mulligan T, Johnson ML, Weltman A, Evans WS, Iranmanesh A. (2001). Neurophysiological regulation and target-tissue impact of the pulsatile mode of growth hormone secretion in the human. Growth Hormone & IGF Research, 11(Suppl A), S25–S37. DOI: 10.1016/s1096-6374(01)80005-8. PMID: 11527085
15. Walker RF. (2006). Sermorelin: a better approach to management of adult-onset growth hormone insufficiency? Clinical Interventions in Aging, 1(4), 307–308. DOI: 10.2147/ciia.2006.1.4.307. PMID: 18046908
16. Arvat E, Maccario M, Di Vito L, Broglio F, Benso A, Gottero C, Papotti M, Muccioli G, Dieguez C, Casanueva FF, Deghenghi R, Camanni F, Ghigo E. (2001). Endocrine activities of ghrelin, a natural growth hormone secretagogue, in humans: comparison and interactions with hexarelin, a nonnatural peptidyl GHS, and GH-releasing hormone. Journal of Clinical Endocrinology and Metabolism, 86(3), 1169–1174. DOI: 10.1210/jcem.86.3.7314. PMID: 11238504
17. Hartman ML, Veldhuis JD, Thorner MO. (1993). Normal control of growth hormone secretion. Hormone Research, 40(1–3), 37–47. PMID: 8300049