Growth Hormone Secretagogues Compared — VialBase Guides

Growth hormone secretagogues (GHS) are a class of peptides that stimulate the body’s own pituitary gland to release growth hormone. Unlike exogenous HGH, secretagogues work within the physiological GH axis — they prompt the body to produce GH rather than supplying it directly. This distinction matters for pulse preservation, safety profile, and regulatory status.

This guide compares the five most researched GH secretagogues in active use: CJC-1295 (with and without DAC), Ipamorelin, GHRP-2, GHRP-6, and Tesamorelin.

How GH Secretagogues Work

Two receptor pathways drive GH release from the pituitary:

1. GHRH pathway: Growth hormone-releasing hormone (GHRH) binds to GHRH receptors on pituitary somatotrophs, triggering GH release. CJC-1295, Sermorelin, and Tesamorelin mimic this pathway.

2. Ghrelin/GHS-R pathway: Ghrelin (and ghrelin mimetics) bind to GHS-R1a receptors, providing a separate and synergistic GH-releasing signal. GHRP-2, GHRP-6, and Ipamorelin work through this pathway.

Critical insight: Combining one compound from each pathway produces a synergistic release — the combined GH pulse is far greater than either compound alone. This is the pharmacological basis for stacking a GHRH analog with a GHRP.

Compound Profiles

CJC-1295 (with DAC)

CJC-1295 with DAC (Drug Affinity Complex) is a modified GHRH analog that binds to serum albumin, extending its half-life to approximately 6–8 days. A single injection maintains elevated GHRH signaling for nearly a week.

Mechanism: GHRH receptor agonist with extended half-life via albumin binding Typical dosing: 1–2 mg once or twice weekly Half-life: ~6–8 days

Pros:

• Infrequent dosing (weekly injections)
• Sustained GH elevation

Cons:

• Continuous stimulation may reduce natural GH pulsatility
• Less mimicry of physiological GHRH pulsing
• Higher per-dose cost

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

Without the DAC modification, CJC-1295 behaves as a short-acting GHRH analog — very similar to the body’s own GHRH.

Mechanism: GHRH receptor agonist (short-acting) Typical dosing: 100–200 mcg, 1–3× daily Half-life: ~30 minutes

Pros:

• Preserves pulsatile GH release pattern
• Better mimicry of natural GHRH physiology
• Often preferred when stacking with GHRPs

Cons:

• Requires multiple daily injections
• More complex dosing schedule

Ipamorelin

Ipamorelin is widely regarded as the most selective ghrelin mimetic available. It stimulates GH release with minimal off-target effects on cortisol, prolactin, or appetite.

Mechanism: Selective GHS-R1a agonist (ghrelin mimetic) Typical dosing: 200–300 mcg per injection, 1–3× daily Half-life: ~2 hours

Pros:

• Highly selective — minimal cortisol or prolactin increase
• Minimal appetite stimulation
• Well-tolerated side effect profile
• Ideal for stacking with CJC-1295 (no-DAC) or Sermorelin

Cons:

• Lower GH release amplitude compared to GHRP-2 or GHRP-6 alone
• Multiple daily injections required for optimal effect

GHRP-2

GHRP-2 is a potent ghrelin mimetic with a stronger GH release signal than Ipamorelin, but with more off-target activity.

Mechanism: GHS-R1a agonist with moderate cortisol and prolactin stimulation Typical dosing: 100–300 mcg per injection, 1–3× daily Half-life: ~1–2 hours

Pros:

• Stronger GH pulse amplitude than Ipamorelin
• Useful when maximum GH stimulation is the goal

Cons:

• Notable cortisol increase with each dose
• Prolactin elevation — may be relevant for extended use
• Moderate appetite increase

GHRP-6

GHRP-6 was one of the first GHRPs studied extensively. It shares GHRP-2’s GH release potency but is particularly notable for pronounced appetite stimulation.

Mechanism: GHS-R1a agonist with strong ghrelin/appetite activity Typical dosing: 100–300 mcg per injection, 1–3× daily Half-life: ~2–3 hours

Pros:

• Strong GH pulse amplitude
• Appetite stimulation useful for individuals seeking to increase caloric intake
• Long research history

Cons:

• Significant appetite increase — can be a substantial inconvenience
• Cortisol and prolactin elevation similar to GHRP-2
• Less popular than Ipamorelin for general use due to appetite side effect

Tesamorelin

Tesamorelin is a GHRH analog stabilized with a trans-3-hexenoic acid modification that increases its half-life compared to native GHRH. It is FDA-approved for HIV-associated lipodystrophy.

Mechanism: GHRH receptor agonist (modified, longer-acting than Mod-GRF 1-29) Typical dosing: 1–2 mg daily Half-life: ~26–38 minutes (extended vs. native GHRH)

Pros:

• Clinical validation for visceral fat reduction
• FDA approval provides quality standard context
• GHRH pathway without DAC’s extended half-life drawbacks

Cons:

• Primary evidence base is visceral fat reduction, not general GH optimization
• Higher cost
• Less versatile for stacking strategies

Head-to-Head Comparison Table

Stacking Recommendations

The gold standard approach pairs one GHRH-pathway compound with one GHRP:

Beginner / Clean Protocol:

• CJC-1295 (no DAC) + Ipamorelin — most widely used combination; minimal side effects, excellent synergy

Maximum GH Output:

• CJC-1295 (no DAC) + GHRP-2 — higher pulse amplitude; monitor cortisol if running extended cycles

Low Frequency / Convenience:

• CJC-1295 (with DAC) + Ipamorelin — twice weekly injections; note that DAC version sacrifices natural pulsatility

Visceral Fat Primary Goal:

• Tesamorelin alone or + Ipamorelin

Which to Choose

All secretagogue protocols should be cycled (see the peptide cycling guide) to preserve receptor sensitivity and pituitary responsiveness.

This content is for educational purposes only and does not constitute medical advice.