Ipamorelin and CJC-1295: The Growth Hormone Stack Explained

If you've spent more than ten minutes researching growth hormone peptides, you've encountered the combination of Ipamorelin and CJC-1295. It's the most commonly discussed growth hormone (GH) peptide stack — prescribed by peptide therapy clinics, discussed in biohacking communities, and referenced in virtually every GH peptide conversation.

But most discussions skip over a critical question: why these two specifically? What does each one do on its own, and what's the biological logic for combining them?

This guide breaks down both peptides individually, explains the synergy, covers the research, and provides practical protocol information.

How Growth Hormone Release Actually Works

To understand why Ipamorelin and CJC-1295 are combined, you need to understand how your body naturally produces growth hormone.

GH release from the pituitary gland is controlled by two opposing signals:

GHRH (Growth Hormone-Releasing Hormone) — the "go" signal. Released by the hypothalamus, GHRH tells the pituitary to produce and secrete growth hormone.
Somatostatin — the "stop" signal. Also released by the hypothalamus, somatostatin suppresses GH release.

Your body produces GH in pulsatile patterns — bursts of release throughout the day, with the largest pulse occurring during deep sleep. These pulses are the result of the rhythmic interplay between GHRH (go) and somatostatin (stop).

There's a third player: Ghrelin, a hormone produced primarily in the stomach. Ghrelin binds to the GHS-R (growth hormone secretagogue receptor) on the pituitary, amplifying the GH response to GHRH. Think of ghrelin as a "volume knob" — it doesn't initiate GH release on its own, but it makes the pituitary more responsive when GHRH is present.

CJC-1295 mimics GHRH — it provides the "go" signal. Ipamorelin mimics ghrelin — it turns up the volume.

That's the fundamental logic of the stack.

Ipamorelin: The Selective GH Secretagogue

Ipamorelin is a synthetic pentapeptide (5 amino acids) that mimics ghrelin by binding to the GHS-R (growth hormone secretagogue receptor) on pituitary cells. When it binds, it amplifies the pituitary's GH response.

What Makes Ipamorelin Different

Several peptides bind the GHS-R — including GHRP-6, GHRP-2, and hexarelin. Ipamorelin's distinction is its selectivity.

In comparative studies (Raun et al., 1998), ipamorelin was shown to:

Stimulate GH release comparable to GHRP-6 and GHRP-2
Not significantly increase cortisol — unlike GHRP-6, which can raise cortisol levels
Not significantly increase prolactin — unlike GHRP-2 and hexarelin
Not significantly increase hunger — unlike GHRP-6, which strongly stimulates appetite through ghrelin pathways

This selectivity matters because cortisol elevation (stress hormone) and prolactin elevation (can affect libido, mood, and hormonal balance) are undesirable side effects. Ipamorelin provides GH stimulation without these off-target effects — making it the "cleanest" option in the GHS-R agonist category.

Ipamorelin's GH Response

A single dose of ipamorelin produces a GH pulse within 15-30 minutes, peaking at approximately 30-45 minutes, and returning to baseline within 2-3 hours. This mimics the natural pulsatile pattern of GH release rather than producing the sustained, non-physiological elevation seen with exogenous GH injection.

CJC-1295: The GHRH Analog

CJC-1295 is a synthetic analog of GHRH (Growth Hormone-Releasing Hormone) — the 44-amino acid hormone that directly signals the pituitary to produce and release growth hormone.

CJC-1295 exists in two forms, and the distinction is critical:

CJC-1295 with DAC (Drug Affinity Complex)

The original form. DAC is a chemical modification that allows CJC-1295 to bind to albumin (a blood protein), extending its half-life to 6-8 days. This produces a sustained, continuous elevation of GH levels — not the natural pulsatile pattern.

While this sounds appealing for convenience, the continuous GH elevation can lead to GH blunting (the pituitary downregulates its response) and potentially more side effects. CJC-1295 with DAC is less commonly used in modern protocols.

CJC-1295 without DAC (also called Mod GRF 1-29)

This is the form used in the Ipamorelin + CJC-1295 stack. Without DAC, the half-life is approximately 30 minutes — long enough to trigger a meaningful GH pulse, short enough to preserve the natural pulsatile release pattern.

When this article refers to "CJC-1295," it means CJC-1295 without DAC (Mod GRF 1-29) unless otherwise specified.

How CJC-1295 Works

CJC-1295 binds to GHRH receptors on the pituitary and triggers GH synthesis and release. It's essentially a more potent, slightly longer-lasting version of your body's own GHRH.

Key distinction from ipamorelin: CJC-1295 initiates the GH release signal. Ipamorelin amplifies the pituitary's response to that signal. They work on different receptor systems with complementary effects.

Why They're Combined

The combination produces a synergistic GH response — meaning the combined effect is greater than either peptide alone.

Here's the biological logic:

CJC-1295 sends the GHRH signal: "Pituitary, release growth hormone."
Ipamorelin activates the GHS-R: "Pituitary, be MORE responsive to that GHRH signal."
The pituitary receives both signals simultaneously and produces a larger, more robust GH pulse.

This mimics what happens naturally when your body releases both GHRH and ghrelin — which it does during sleep and after exercise. The stack recreates and amplifies this natural synergy.

Research Support

Studies have demonstrated that combining GHRH analogs with GHS-R agonists produces GH responses that are 2-3x greater than either agent alone (Bowers et al., 1990; Veldhuis et al., 2005). While these studies used different specific compounds, the pharmacological principle — GHRH + ghrelin mimetic synergy — is well-established.

Benefits: What GH Peptides Do

Growth hormone itself affects virtually every tissue in the body. By increasing natural GH production through the Ipamorelin + CJC-1295 stack, the expected downstream effects include:

Well-Supported by GH Biology

Improved body composition — GH promotes fat oxidation (especially visceral fat) and supports lean mass. GH-deficient adults who receive GH therapy show significant reductions in body fat and increases in lean mass.
Enhanced recovery — GH plays a direct role in tissue repair, collagen synthesis, and protein turnover. Athletes and physically active individuals commonly report improved recovery between training sessions.
Better sleep quality — The relationship between GH and sleep is bidirectional. Deep sleep triggers GH release, and GH influences sleep architecture. Many users report deeper, more restorative sleep.
Skin and hair quality — GH stimulates collagen production and skin cell turnover. Changes in skin thickness, elasticity, and hydration are among the most commonly reported subjective benefits.

Reported But Less Rigorously Documented

Cognitive improvements — GH receptors exist in the brain, and some users report improved mental clarity and focus. The evidence for cognitive effects of GH optimization is preliminary.
Joint health — Through collagen synthesis and cartilage support. Anecdotal reports are common; controlled data for peptide-stimulated GH specifically is limited.
Increased energy — Commonly reported, likely related to improved sleep quality and metabolic effects.

What GH Peptides Don't Do

It's worth being direct about limitations:

GH peptides are not anabolic steroids. They won't produce dramatic muscle growth on their own. They support recovery and body composition — not pharmacological-level muscle building.
Effects are gradual. Unlike exogenous GH injection (which delivers supraphysiological doses), GH peptides amplify your own production within a physiological range. Expect subtle, cumulative changes over weeks to months — not overnight transformation.
Individual response varies significantly based on age, baseline GH production, sleep quality, diet, exercise habits, and genetics.

Dosing Protocol

Standard Ipamorelin + CJC-1295 Protocol

Peptide	Dose per Injection	Frequency	Timing
Ipamorelin	200-300 mcg	1-3x daily	Before bed (primary); optionally AM and/or post-workout
CJC-1295 (no DAC)	100-200 mcg	1-3x daily	Same timing — inject together

Protocol Notes

Timing matters for this stack. The most important dose is before bed — this amplifies the natural nocturnal GH pulse, which is the largest of the day. Morning and post-workout doses are optional additions.

Inject on an empty stomach. Elevated blood sugar and insulin suppress GH release. Wait at least 2 hours after eating before injecting, and don't eat for 30-60 minutes after injection.

Typical cycle length: 8-12 weeks, followed by 4 weeks off. Some protocols extend to 16 weeks. There is no established human data on optimal cycling.

Reconstitution: Both peptides are reconstituted with bacteriostatic water using standard procedure. Many users reconstitute them in the same vial for convenience (if volumes are compatible) or inject them sequentially.

Use our Peptide Dosage Calculator for exact reconstitution math and syringe draw volumes.

CJC-1295 with DAC Protocol (Less Common)

If using CJC-1295 with DAC instead:

Peptide	Dose	Frequency
CJC-1295 with DAC	2 mg	Once weekly
Ipamorelin	200-300 mcg	Daily at bedtime

The with-DAC version provides continuous GHRH stimulation, so only weekly dosing is needed. However, as noted above, this approach produces less physiological GH patterns.

Side Effects and Safety

Common Side Effects

Water retention — mild fluid retention, especially in the first 2-3 weeks. Usually subsides.
Tingling or numbness in hands and feet (carpal tunnel-like symptoms) — related to GH effects on soft tissue. Typically resolves with dose reduction.
Increased hunger — CJC-1295 can mildly increase appetite. This is minimal compared to GHRP-6.
Headache — occasionally reported, usually mild and transient.
Injection site reactions — minor redness or irritation.
Fatigue or drowsiness — especially with the bedtime dose (which is partly the point — enhanced sleep).

Serious Considerations

Blood sugar — GH has anti-insulin effects. Chronic GH elevation can impair insulin sensitivity. Monitoring fasting glucose and HbA1c is recommended, especially for individuals with pre-diabetes or metabolic concerns.
Cancer risk (theoretical) — GH and IGF-1 promote cell proliferation. While GH peptides produce physiological (not supraphysiological) levels, the theoretical concern about promoting growth of existing tumors applies. Avoid with active cancer or cancer history.
Joint pain — at higher doses, GH-related joint discomfort can occur. This is a sign to reduce dose.

Who Should Avoid GH Peptides

Active cancer or cancer history
Pregnant or breastfeeding individuals
Type 1 diabetes (GH significantly affects insulin dynamics)
Active diabetic retinopathy
Individuals under 25 (growth plates may not be closed)

Ipamorelin + CJC-1295 vs. Other GH Options

Option	Mechanism	Pros	Cons
Ipamorelin + CJC-1295	Stimulates natural GH	Pulsatile (physiological), selective, well-tolerated	Requires 1-3x daily injection, effects are gradual
MK-677 (Ibutamoren)	Oral GH secretagogue	Oral (no injection), convenient	Increases hunger significantly, 24-hour GH elevation (less physiological), can affect insulin sensitivity more
Exogenous HGH	Direct GH injection	Strongest, most predictable effect	Expensive, suppresses natural production, higher side effect risk, legal/regulatory issues
GHRP-6	GHS-R agonist (like ipamorelin)	Strong GH release	Increases cortisol, prolactin, and hunger significantly
Sermorelin	GHRH analog (like CJC-1295)	FDA-approved for GH deficiency diagnosis, well-studied	Shorter half-life than CJC-1295, less potent

The Ipamorelin + CJC-1295 combination occupies a middle ground: more targeted than MK-677, more physiological than exogenous HGH, and cleaner than older secretagogues like GHRP-6.

What to Expect: Timeline

Based on community reports and the known biology of GH optimization:

Weeks 1-2: Improved sleep quality (often the first noticeable change). Mild water retention possible.
Weeks 2-4: Deeper sleep patterns. Beginning of recovery improvements. Some report improved skin quality.
Weeks 4-8: Body composition changes become noticeable — gradual fat reduction and muscle tone improvement. Recovery between workouts improves. Energy levels stabilize.
Weeks 8-12: Cumulative effects on skin, hair, and body composition. Most users report this as the period where benefits become clearly apparent.

Individual results vary significantly. Managing expectations is important — GH peptides produce real but gradual effects, not dramatic overnight changes.

Key Takeaways

Ipamorelin + CJC-1295 is the most popular GH peptide stack because they target complementary receptor systems for synergistic GH release
CJC-1295 (no DAC) mimics GHRH — the "go" signal for GH production
Ipamorelin mimics ghrelin — amplifying the pituitary's response to GHRH
Always use CJC-1295 without DAC for the stack (preserves pulsatile release)
Standard dosing: 200-300 mcg ipamorelin + 100-200 mcg CJC-1295, 1-3x daily, with bedtime as the primary dose
Inject on an empty stomach (insulin suppresses GH release)
Effects are gradual and cumulative — expect 4-12 weeks for noticeable changes
Monitor blood sugar and IGF-1 levels with your physician
Explore our Peptide Dosage Calculator for reconstitution math

For peptide-specific dosing details, see our Ipamorelin Dosage Guide and CJC-1295 Dosage Guide.

This article is for educational and informational purposes only. It is not medical advice. Ipamorelin and CJC-1295 are not FDA-approved. Always consult with a qualified healthcare provider before starting any peptide protocol.

Key References:

Raun K, et al. "Ipamorelin, the first selective growth hormone secretagogue." Eur J Endocrinol. 1998;139(5):552-561.
Bowers CY, et al. "On the actions of the growth hormone-releasing hexapeptide, GHRP." Endocrinology. 1990;128(4):2027-2035.
Veldhuis JD, et al. "Motivating concepts underlying the GHRH-ghrelin synergy." Endocrine. 2005;27(1):5-17.
Teichman SL, et al. "Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295." J Clin Endocrinol Metab. 2006;91(3):799-805.
Nass R, et al. "Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults." Ann Intern Med. 2008;149(9):601-611.