GHRP-6 vs GHK
Side-by-side comparison of key properties, dosing, and research.
- Summary
- GHRP-6 is the original synthetic GH-releasing peptide and a potent ghrelin receptor agonist. It produces strong GH pulses but is notorious for a significant hunger surge 30–45 minutes post-injection. This hunger side effect makes it less preferred than Ipamorelin or GHRP-2 for most protocols but can be useful in patients with appetite deficiency.
- GHK is the natural tripeptide (Gly-His-Lys) released from human albumin that activates tissue remodeling, collagen synthesis, and anti-aging gene expression. The copper-free form is the biological signaling molecule; it chelates copper in tissue to form GHK-Cu but also has independent biological activity.
- Half-Life
- 15–60 minutes
- Extremely short as free peptide; tissue binding extends local effects
- Admin Route
- SubQ, Intranasal
- SubQ, Topical, Oral
- Research
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- Typical Dose
- 100–300 mcg
- 100–500 mcg
- Frequency
- 2–3 times daily
- Daily or 5x per week
- Key Benefits
- Strong GH stimulation
- Elevated IGF-1
- Muscle growth and recovery support
- Potential anti-inflammatory effects at GI level
- Useful for patients with appetite deficiency or cachexia
- Enhanced recovery from training
- Stimulates collagen and extracellular matrix synthesis
- Activates tissue repair gene expression programs
- Anti-aging: reverses 57% of age-related gene changes
- Antioxidant and anti-inflammatory
- Wound healing and skin barrier repair
- Improves skin laxity, texture, and radiance
- Neuroprotective (stimulates NGF, BDNF)
- Anti-fibrotic in liver and lung models
- Side Effects
- Intense hunger surge (30–45 min post-injection)
- Water retention
- Elevated cortisol (modest)
- Elevated prolactin (modest)
- +2 more
- Excellent safety profile (naturally occurring peptide)
- Rare: mild injection site reaction (SC)
- No significant adverse effects identified in research
- Stacks With
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