CJC-1295 + Ipamorelin: The Clean GH Stack Explained

CJC-1295 plus ipamorelin is a research pairing of two growth-hormone secretagogues. CJC-1295, a GHRH analog, raises how much GH a pituitary cell can release per pulse; ipamorelin, a selective ghrelin-receptor agonist, triggers that pulse. They act on separate receptors in the same cell, and co-activation produces a larger, super-additive GH release than either compound alone.

If you have spent any time around growth-hormone peptides, you have run into this pairing. CJC-1295 and ipamorelin are the classic GH stack, the one that quietly replaced the older, messier combinations the bodybuilding world used to run. People treat it as a single product, and for good reason: you almost never want one without the other.

The short version is that these two peptides act on the pituitary to release more endogenous growth hormone, from two different angles at once, and the two angles add up to more than the sum of their parts. That is the mechanism. It is not exogenous HGH, and the selective version of the stack triggers GH release without the cortisol, prolactin and strong appetite signalling that the older GHRPs are characterised as carrying.

A word on where Primogen sits before we go further: we carry CJC-1295 and ipamorelin both as standalone vials and as a pre-mixed CJC-1295 + ipamorelin blend, since the blend is how most people actually run it. All of it is sold as research material, and this guide is about explaining the mechanism honestly, including the parts the evidence does not yet cover.

How do CJC-1295 and ipamorelin compare side by side?

Side by side, CJC-1295 (no-DAC) is the GHRH-receptor analog that sets pulse amplitude, while ipamorelin is the selective ghrelin-receptor (GHS-R1a) agonist that triggers the pulse, with a longer half-life and no cortisol or prolactin spillover. The table breaks down class, receptor, half-life and typical community dosing for each.

For the wider family this stack belongs to, and how GH secretagogues differ from injecting GH directly, see GH secretagogues explained.

How does the CJC-1295 + ipamorelin stack actually work?

The stack works because both peptides increase GH output from the pituitary but reach that endpoint through two completely different receptors. CJC-1295 binds the GHRH receptor to raise pulse amplitude; ipamorelin binds the ghrelin receptor to trigger the pulse. Activating both at once produces a super-additive GH release.

CJC-1295 is a GHRH analog. Growth-hormone-releasing hormone is the signal the hypothalamus normally sends to tell the pituitary to make and release GH. CJC-1295 is a synthetic, longer-lasting version of that signal. It binds the GHRH receptor and drives the cAMP/PKA pathway, which ramps up GH gene transcription and primes the cell to release a bigger pulse (Jetté et al. 2005). On its own it raises the amplitude of GH release, how much comes out per pulse, but it does not strongly trigger the pulse itself.

Ipamorelin is a GHRP, a ghrelin mimetic. GHRP (growth-hormone-releasing peptide) means a peptide that triggers a GH pulse, and a ghrelin mimetic is one that does it by copying ghrelin, the stomach's hunger hormone. It binds a different receptor entirely, the ghrelin receptor (GHS-R1a). That sets off a calcium-driven cascade inside the same pituitary cell and forces a discrete pulse of stored GH out the door. It also eases off the somatostatin "brake" that normally holds GH back. So ipamorelin is the trigger.

Put them together. One peptide raises the ceiling, the other pulls the trigger, and they act on independent receptors and independent second-messenger systems in the very same cell. Co-activating both produces a super-additive GH release. In pig co-administration models, the combined GH output was roughly two to four times the area-under-the-curve of either compound alone (Jorgensen et al. 2001), and in healthy men, GHRH and a GHRP given together produced clearly synergistic GH release at submaximal doses (Bowers et al. 1990). This is the closest pharmacological imitation of the natural ghrelin-plus-GHRH co-secretion that drives nocturnal GH pulses.

In short: CJC-1295 sets how big the pulse can be, ipamorelin makes the pulse happen, and doing both at once gets you more GH than the two added separately.

The honest framing on the synergy: the mechanism is solid and the synergy is shown in pig models and small human GHRH-plus-GHRP studies, but the specific CJC-1295-plus-ipamorelin blend has never been run through a formal trial of its own. The pharmacology is well-founded; the exact body-composition numbers people quote are community-derived, not from a registration study.

CJC-1295 with DAC vs without DAC: which one belongs in the stack?

For the classic ipamorelin stack the answer is CJC-1295 without DAC. The two forms differ enough that they behave like two different compounds: with-DAC has a multi-day half-life and produces a continuous "GH bleed," while no-DAC clears in about 30 minutes and gives a short, sharp pulse that lines up with ipamorelin's own pulse.

CJC-1295 with DAC carries a "Drug Affinity Complex" that binds it to serum albumin, stretching its half-life out to roughly 5.8 to 8.1 days (Teichman et al. 2006). One injection keeps GHRH signalling elevated for the better part of a week, a sustained "GH bleed." Convenient (weekly dosing), but it trades away the natural pulse pattern for a more continuous tone.

CJC-1295 without DAC, also sold as Modified GRF 1-29 or Mod GRF 1-29, has a half-life of about 30 minutes. It briefly amplifies a single GH pulse and then clears. This is the version that pairs cleanly with ipamorelin's own short pulse, and it is the one most people mean when they talk about "the stack." Timed before sleep onset, the pulse coincides with the natural nocturnal GH surge.

Which to choose comes down to philosophy. The no-DAC form keeps GH release pulsatile, meaning it comes out in bursts rather than a steady stream, which is how the axis (the brain-to-pituitary hormone signalling chain that governs GH) evolved to work and is associated with preservation of the somatostatin feedback loop. Continuous GHRH-receptor analogs like the DAC form raise GH without fully maintaining that pulsatile pattern (Ionescu & Frohman 2006). The performance and longevity community leans heavily toward no-DAC plus ipamorelin for exactly that reason. Primogen's blend uses the no-DAC form, paired with ipamorelin, because that is the configuration the stack was built around.

Why ipamorelin instead of the older GHRPs?

Ipamorelin is favoured because it is selective: it releases GH without the cortisol, prolactin and strong appetite signalling characterised for the earlier GHRPs. GHRP-6, GHRP-2 and hexarelin came before it and all release GH, but GHRP-6 is associated with marked hunger, and GHRP-2 and hexarelin with raised cortisol and prolactin alongside the GH.

Ipamorelin's defining trait, established back in the original characterisation work, is selectivity. Raun et al. (1998) described it as the first GHRP-receptor agonist with a selectivity for GH release on par with GHRH itself, and reported that it did not meaningfully raise ACTH (the pituitary signal that drives cortisol) or cortisol even at doses more than 200 times the dose needed to release GH. That selectivity is the reason it displaced the older GHRPs: the GH pulse without the stress-hormone spillover or appetite spike documented for the others, which is why it is the GHRP most often selected for long-running research protocols.

What is the typical CJC-1295 + ipamorelin dose?

The most commonly reported community protocol is a ~100 mcg saturation dose of ipamorelin (roughly 1 mcg/kg) paired 1:1 with 100 mcg CJC-1295 (no-DAC) per injection, taken before bed and fasted. Everything in this section is community and vendor practice, not a clinical protocol. There is no registration-trial dose for this stack used this way, so what follows is how it is actually run, reported as such.

The saturation dose. For ipamorelin, the community consensus is a saturation dose of around 100 mcg (roughly 1 mcg/kg) per injection. Reports describe diminishing returns past that point, with the GH pulse not getting much bigger, and pushing well above it (300 mcg-plus, chronically) is where the cortisol and prolactin pathways that ipamorelin otherwise spares are described as starting to engage. More is not better here; it is receptor saturation, not filling a tank.

The classic pairing. The standard pattern is 100 mcg ipamorelin plus 100 mcg CJC-1295 (no-DAC) per shot, both drawn from the same blend. Some people run 100/200.

Worked reconstitution example. Take a 5 mg (5,000 mcg) blend vial reconstituted with 2 mL of bacteriostatic water. That gives 2,500 mcg per mL, or 250 mcg per 0.1 mL. On a U-100 insulin syringe (100 units = 1 mL), 0.1 mL is the 10-unit mark, so a 100 mcg draw sits at the 4-unit mark (0.04 mL = 100 mcg). Add 0.5 mL more water (2.5 mL total) and the maths shifts to 2,000 mcg/mL, putting a 100 mcg draw at the 5-unit mark. Always recompute the unit mark for your own vial size and water volume rather than reusing a number from a different reconstitution.

Timing. Two rules dominate the reported practice. First, dose before bed, so the pulse lands on top of the natural sleep-onset GH surge. Second, dose fasted, at least two hours after the last meal and ideally not eating for 30 minutes after, because insulin and dietary fat both blunt the GH pulse (insulin suppresses GH release; fat drives somatostatin). A single pre-bed shot is the most common protocol. People targeting body composition add a second (fasted morning or post-workout) or a third pulse across the day.

If you run the DAC version instead, the logic flips: roughly 1-2 mg once or twice weekly for the sustained tone, often with daily ipamorelin shots layered on for the pulse.

Cycling. Common patterns are 5-days-on / 2-off, or 8 to 12 weeks on with 4 weeks off, mostly aimed at avoiding receptor desensitisation. None of these schedules is backed by trial data; they are convention. If you are new to drawing and dosing peptides, how to reconstitute and dose walks through the practical side, and peptide stacking covers how this fits alongside other compounds.

What does the research timeline for this stack look like?

The documented effect is pharmacokinetic and slow, not a switch. Here is the timeline with the trial-grounded pharmacology separated from what the community reports anecdotally:

• Acute (the pulse): the GH pulse itself is immediate. For ipamorelin, human PK work reports a GH peak around 40 minutes post-dose, returning toward baseline within a couple of hours (Gobburu et al. 1999, the study of how the drug rises and clears in blood). A mild head-rush or facial flush shortly after injecting is commonly reported in handling notes and typically passes in minutes.
• Weeks 2-4 (community-reported): users report mild water retention and occasional peripheral tingling at higher doses. These are reports, not trial outcomes.
• Weeks 4-12 (mechanism plus community reports): IGF-1 is the downstream growth factor that mediates much of GH's action; community bloodwork reports describe roughly a 20-30% IGF-1 rise at saturation dosing, used informally as an "is it active" check. This figure is community-derived, not from a controlled trial of the stack.
• Beyond 12 weeks: there is no published human safety data past this point. The theoretical concerns below become more relevant the longer a protocol runs.

Whatever is observed is physiological in scale: the mechanism amplifies endogenous pulses within the pituitary's ceiling rather than flooding the system the way injected HGH does. Any vendor promising HGH-level outcomes from a secretagogue stack (a secretagogue is something that prompts a gland to release its own hormone) is overstating what the pharmacology supports.

What are the side effects of CJC-1295 + ipamorelin?

The reported side-effect profile is dominated by mild, GH-related effects rather than anything dramatic. In its one completed human trial ipamorelin was well tolerated (Beck et al. 2014). Commonly reported effects:

• Facial flushing and a head-rush in the first 5-15 minutes after injecting. Commonly reported, mostly attributed to the CJC-1295 component, typically gone within half an hour.
• Water retention and, at higher or longer doses, tingling or numbness in the hands and fingers. This is the classic GH-mediated fluid effect (the same mechanism behind carpal-tunnel-like symptoms reported with GH), and reports describe it easing at lower doses.
• Injection-site reactions, mild redness or itching, commonly reported and short-lived.
• Mild appetite uptick in some reports. Ipamorelin is still a ghrelin agonist, so some hunger signalling is plausible, but it is characterised as far milder than GHRP-6.

The selectivity is the headline. Because ipamorelin is selective, the stack does not carry the cortisol, prolactin and strong-hunger profile of GHRP-2 or GHRP-6. That selectivity is the reason it is the GHRP most often chosen for long research protocols.

Now the parts the marketing tends to skip:

• Insulin sensitivity can drift with chronic GH elevation. GH is counter-regulatory to insulin (it works against insulin's blood-sugar-lowering action), so sustained high-dose GH elevation over months is associated with rises in fasting glucose and HbA1c. A relevant marker to monitor with bloodwork in any long-term protocol.
• The long-term safety file is thin. No published human data exists beyond roughly 12 weeks of continuous use for these compounds. The years-long community cruise protocols are genuinely uncharted.
• The IGF-1 / cancer question is theoretical but not nothing. Anything that chronically raises IGF-1 sits under a mechanistic question mark. A large UK Biobank analysis (Knuppel et al. 2020, ~394,000 people) found higher circulating IGF-I associated with a small increase in colorectal and prostate cancer risk (hazard ratio around 1.08 per 5 nmol/L). That is an association with IGF-1 levels generally, not direct evidence about these peptides, and there is no long-term CJC-1295 or ipamorelin cancer data either way.
• Ipamorelin's one Phase 2 efficacy trial failed. Its only completed human efficacy study was in postoperative ileus, and it missed its primary endpoint (Beck et al. 2014). It was well tolerated, but the body-composition, sleep and anti-ageing uses that drive demand have never been through a completed human efficacy trial. The mechanism is well-founded; the outcome evidence for these specific uses is community-grade.

Markers researchers track in the literature: IGF-1 (the direct downstream marker), fasting glucose and HbA1c, and, under high chronic dosing, prolactin and morning cortisol as a selectivity check.

Who researches the CJC-1295 + ipamorelin stack?

The stack is researched mainly within the GH-secretagogue, recovery and longevity communities. The groups that gravitate to it:

• Lifters and bodybuilders, who are drawn to GH-axis research over injecting GH directly, on cost and pulsatility grounds.
• Biohackers and longevity-minded researchers, who prefer the pulsatile profile of a secretagogue over the flat-line of exogenous HGH or oral MK-677, on the argument that preserving the natural rhythm is the more conservative long game.
• Sleep and recovery-focused researchers, including time-poor professionals, who run a single pre-bed pulse and nothing more.

A couple of honest disqualifiers. For a drug-tested athlete, both peptides are on the WADA Prohibited List at all times. And alongside exogenous HGH or MK-677, the stack is largely redundant: HGH bypasses the pituitary entirely, and MK-677 hits the same receptor as ipamorelin.

Where does CJC-1295 + ipamorelin come from, and how is it tested?

This category, like nearly all research peptides, comes overwhelmingly out of China, and rigorous per-batch third-party testing is thin across the whole sector. This product line has been third-party tested at the supplier level, and that is a reference figure, not a guarantee about any individual vial. Read the certificate of analysis on whatever you buy and understand what it does and does not prove. We would rather tell you that plainly than pretend the industry is something it is not.