Growth Hormone Peptides

Overview of Growth Hormone Secretagogues

Growth hormone naturally declines with age — by age 60, circulating GH can be 50% lower than peak levels in youth. GH secretagogues are peptides engineered to stimulate the pituitary gland to release its endogenous (naturally-produced) GH. Unlike pharmaceutical GH (exogenous replacement), secretagogues work by enhancing the body's own GH production.

The GH axis involves two primary signaling pathways:

• GHRH receptor (growth hormone releasing hormone): Stimulation increases GH release amplitude and frequency. This is the "accelerator."
• GHSR receptor (ghrelin receptor): Stimulation triggers pulsatile GH release in response to fasting, stress, sleep. This is the "pulse trigger."

GH secretagogues are classified by which receptor(s) they activate:

• GHRH analogs: Mimic GHRH; increase GH amplitude.
• Ghrelin mimetics (GHRPs): Mimic ghrelin; trigger pulsatile GH release and cortisol/prolactin elevation (side effect).
• Combination agents: Act on both pathways or have additional mechanisms (MK-677, tesamorelin).

GHRH Analogs: The GH Amplifiers

CJC-1295 (Modified GRF 1-29 / Mod GRF)

Mechanism: Synthetic GHRH analog. Acts on GHRH receptor to increase GH secretion amplitude.

• Half-life: 30 minutes (no DAC version); 6-8 days (with DAC version).
• Dosing: 100-200 mcg per injection, 2-3x daily (use the no-DAC version; DAC version blunts pulsatile GH).
• Timing: Inject fasted, 15-30 minutes before Ipamorelin for optimal synergy.
• Benefits: Strong GH stimulation, minimal off-target hormone effects (no cortisol/prolactin elevation).
• Downsides: Weak alone; highly effective only when stacked with a ghrelin mimetic.
• Timeline: GH elevation seen within 15 min; sustained for 4-6 hours post-injection.

Sermorelin

Mechanism: Another GHRH analog, though older than CJC-1295.

• Half-life: 6-12 minutes; shorter than CJC-1295.
• Dosing: 100-300 mcg per injection, typically 2-3x daily.
• Availability: FDA-approved for treating GH deficiency in children; legal status in adults varies.
• Benefits: Clean GH stimulation; legitimate pharmaceutical in some contexts.
• Downsides: More expensive; no clear advantage over CJC-1295. Very short half-life requires precise timing.
• Comparison: CJC-1295 is generally preferred in research peptide space due to longer half-life and cost.

Ghrelin Mimetics (GHRPs): The Pulse Triggers

Ipamorelin

Mechanism: Selective ghrelin receptor (GHSR-1a) agonist. Triggers pulsatile GH release with minimal off-target effects.

• Half-life: 15-30 minutes.
• Dosing: 100-300 mcg per injection, 2-3x daily (commonly 200 mcg).
• Timing: Fasted injection; synergizes with CJC-1295 when dosed simultaneously.
• Benefits: Strongest GH-selective ghrelin mimetic; minimal cortisol/prolactin elevation; excellent side effect profile.
• Downsides: Modest GH elevation when used alone (becomes powerful only in stacks).
• Community status: Most popular GHRP in modern protocols due to clean safety profile.

GHRP-2 (Growth Hormone Releasing Peptide-2)

Mechanism: Ghrelin receptor agonist. Potent GH stimulation but with significant off-target effects.

• Half-life: 30 minutes to 1 hour.
• Dosing: 100-300 mcg, 2-3x daily.
• GH potency: Comparable to Ipamorelin.
• Downsides: Elevates cortisol significantly (undesirable for cutting or chronic stress protocols). Also raises prolactin (potential for gynecomastia, sexual dysfunction). These effects limit its use in modern protocols.
• Status: Less popular than Ipamorelin due to side effects, though some users find it effective for specific goals.

GHRP-6 (Growth Hormone Releasing Peptide-6)

Mechanism: Ghrelin receptor agonist with similar potency to GHRP-2.

• Half-life: Similar to GHRP-2.
• Dosing: 100-300 mcg, 2-3x daily.
• Unique side effect: Causes intense hunger (some users view this as beneficial for bulking; others find it unmanageable).
• Cortisol/prolactin: Similar elevation to GHRP-2.
• Status: Less popular than both GHRP-2 and Ipamorelin. Hunger effect is significant drawback for fat loss protocols.

Hexarelin

Mechanism: Ghrelin receptor agonist with the highest GH-releasing potency.

• Half-life: 30-50 minutes.
• Dosing: 100 mcg, 2-3x daily (often lower than other GHRPs due to high potency).
• GH elevation: Strongest among GHRPs; comparable or superior to CJC+Ipamorelin stacks in some studies.
• Downsides: Cortisol and prolactin elevation similar to GHRP-2/6. Tachyphylaxis (rapid tolerance buildup) is common — users often cycle on 12 weeks, off 4 weeks to reset receptor sensitivity.
• Status: Powerful but less popular due to tolerance issues and side effects. Considered advanced peptide.

Comparison: GHRH vs. Ghrelin Mimetics

Mixed-Mechanism GH Secretagogues

MK-677 (Ibutamoren)

Mechanism: Oral ghrelin receptor agonist (mimics ghrelin without being a peptide). Works similarly to ghrelin mimetic peptides.

• Administration: Oral (tablet/capsule); not an injection.
• Dosing: 15-25 mg once daily, typically in evening.
• Half-life: 4-6 hours; accumulates with daily dosing.
• GH elevation: Significant and sustained. Some studies show GH elevation of 60-80% above baseline.
• Advantages: Convenient oral administration; no injections; works 24/7 with daily dosing.
• Downsides: Increases hunger (not ideal for fat loss). Elevates prolactin. Appetite increase is more pronounced than most peptides.
• Stacking: Can be combined with CJC-1295 for additional GH amplification, though less common than peptide stacks.
• Timeline: Effects build over 1-2 weeks. Stopping immediately reverses appetite changes (unlike some peptides with longer half-lives).

Tesamorelin

Mechanism: GHRH analog with peptide modifications for enhanced stability and longer half-life.

• Half-life: 26-38 minutes (longer than basic GHRH analogs, shorter than CJC with DAC).
• Dosing: 1-2 mg daily (much higher than other peptides, though total nanomolar amount is similar).
• Approval status: FDA-approved for HIV-associated lipodystrophy (abdominal fat accumulation). Can be prescribed off-label.
• Benefits: Strong GH elevation; pharmaceutical-grade purity; legitimate medical use in some contexts.
• Downsides: Expensive; no clear advantage over CJC-1295 + Ipamorelin for general use.
• Status: Less common in research peptide space; more commonly obtained through medical channels.

Which GH Secretagogue to Choose?

For General Body Recomposition

Best choice: CJC-1295 (no DAC) + Ipamorelin stack

• Powerful synergistic GH elevation without cortisol/prolactin side effects.
• Dosing: 100-200 mcg each, 2-3x daily (fasted timing).
• Clean safety profile; most popular in modern protocols.

For Lean Bulking (Muscle Gain Priority)

Best choice: CJC-1295 + Ipamorelin (same as above), or add TB-500 for recovery

• CJC+Ipa promotes lean mass gain; TB-500 enhances recovery from high-volume training.
• Mild increase in appetite acceptable during bulk.

For Cutting/Fat Loss

Best choice: CJC-1295 + Ipamorelin, or consider GH fragments (Fragment 176-191)

• CJC+Ipa: Minimal appetite increase; clean GH elevation supports fat loss and lean mass preservation.
• Avoid: GHRP-6 (hunger) or MK-677 (appetite increase incompatible with deficit).
• GH fragments (Fragment 176-191): Direct lipolytic activity without systemic GH effects.

For Sleep Optimization and Recovery

Best choice: Ipamorelin alone, pre-sleep (100-200 mcg)

• Pre-sleep GH pulse naturally enhances deep sleep and recovery.
• Single-peptide simplicity; minimal side effects.

For Advanced/Experienced Users Seeking Maximum GH

Consider: CJC-1295 + Hexarelin (instead of Ipamorelin)

• Hexarelin is the most potent ghrelin mimetic.
• Downsides: More cortisol/prolactin elevation; tolerance buildup (requires cycling).
• Use only if CJC+Ipamorelin insufficient and willing to manage side effects.

For Convenience (Non-Injection Users)

Consider: MK-677 (oral)

• Tablet form; 15-25 mg daily.
• Downsides: Appetite increase more pronounced than most peptides; less precise control than injections.

For Medical/Legitimacy Preference

Consider: Sermorelin or Tesamorelin

• Both have legitimate pharmaceutical uses.
• Tesamorelin FDA-approved for lipodystrophy.
• Cost is higher; no clear functional advantage over CJC+Ipamorelin stack.

GH Secretagogue Comparison Table

Stacking and Combination Protocols

Synergistic Stack: CJC-1295 + Ipamorelin (Gold Standard)

• Dosing: 100-200 mcg each, injected together, 2-3x daily.
• Timing: AM (fasted), pre-workout (fasted), pre-sleep (fasted 2+ hours).
• Duration: 8-16 weeks, then 4-6 week break.
• Effect: Large pulsatile GH releases; synergistic amplification.

Triple Stack: CJC-1295 + Ipamorelin + TB-500

• Dosing: CJC+Ipa as above, plus 2-5 mg TB-500 once weekly.
• Purpose: Maximal GH-driven lean mass + superior recovery from training.
• Timeline: For serious athletes/bodybuilders during intensive training blocks.

Practical Stack: CJC-1295 + Ipamorelin + MK-677

• Rationale: Inject CJC+Ipa for pulsatile GH; take MK-677 daily for sustained GH support.
• Benefit: 24/7 GH elevation from two complementary mechanisms.
• Caveat: Appetite increase more pronounced; suited for bulking phases.

What NOT to Stack

• Multiple ghrelin mimetics (GHRP-2 + GHRP-6 + Ipamorelin): Redundant; increases cortisol/prolactin without proportional GH benefit.
• Multiple GHRH analogs (CJC + Sermorelin + Tesamorelin): Redundant; no additive benefit.
• CJC-1295 with DAC + Ipamorelin: DAC version has long half-life and blunts pulsatile release; incompatible with Ipamorelin's pulsatile mechanism.

Side Effects and Safety by Peptide

Cost Considerations

GH secretagogue costs vary widely based on source, quantity, and purity. Here's a rough breakdown for research-grade peptides:

• CJC-1295 (10 mg vial): $50-100.
• Ipamorelin (10 mg vial): $40-80.
• Sermorelin (5 mg vial): $60-150 (more expensive; pharmaceutical grade).
• GHRP-2 or GHRP-6 (10 mg): $30-70.
• Hexarelin (10 mg): $70-150.
• MK-677 (30 tablets, 25 mg each): $80-150.
• Tesamorelin (pharmaceutical, 2 mg vial): $200-400 per vial (expensive; often requires prescription).

Cost per Cycle (8 weeks, average doses)

• CJC-1295 + Ipamorelin stack: ~$200-400 for complete 8-week cycle (two 10 mg vials each).
• MK-677 alone: ~$80-150 for 8-week cycle (single bottle of 30 tablets).
• Sermorelin or Tesamorelin: $400-800+ (pharmaceutical-grade, higher cost).

Value for money: CJC-1295 + Ipamorelin stack offers the best GH effect per dollar. MK-677 is more convenient but less precise control.

GH Secretagogue FAQ