Side-by-side comparison of mechanisms, dosing, interactions, and stacking potential.
| GHK (without copper) | GHRP-2 | |
|---|---|---|
| Category | Peptides | Peptides |
| Standard Dose | Research indicates 1-3% concentration in topical formulations. Injectable dosing follows GHK-Cu protocols at 1-2 mg daily. | Research indicates 100-300 mcg administered 1-3 times daily via subcutaneous injection. |
| Timing | Topical application morning and evening. Injectable in evening. | On empty stomach, bedtime administration preferred. Wait 2+ hours after last meal. |
| Cycle Duration | Topical use can be ongoing indefinitely. Injectable cycles 8-12 weeks. | 8-16 week cycles. |
| Evidence Level | moderate_human | moderate_human |
GHK (glycyl-L-histidyl-L-lysine) is a naturally occurring tripeptide found in human plasma, saliva, and urine that has an extremely high affinity for copper(II) ions. Even without exogenously complexed copper, GHK rapidly chelates available copper in biological systems, making copper-free GHK functionally similar to GHK-Cu in vivo. The peptide stimulates collagen and glycosaminoglycan synthesis, modulates metalloproteinase activity, resets gene expression patterns toward a healthier state (affecting 31.2% of human genes), and activates wound healing cascades.
Research indicates 1-3% concentration in topical formulations. Injectable dosing follows GHK-Cu protocols at 1-2 mg daily.
Topical application morning and evening. Injectable in evening.
Topical use can be ongoing indefinitely. Injectable cycles 8-12 weeks.
GHRP-2 (Growth Hormone Releasing Peptide-2) is a synthetic hexapeptide GHS-R1a agonist that is the most potent of the GHRP family for GH release. It stimulates pituitary GH secretion through the ghrelin receptor while also modulating hypothalamic GHRH and somatostatin pathways. GHRP-2 increases GH, cortisol, prolactin, and ACTH release, but with less appetite stimulation than GHRP-6. It also has demonstrated anxiolytic properties and sleep-promoting effects.
Research indicates 100-300 mcg administered 1-3 times daily via subcutaneous injection.
On empty stomach, bedtime administration preferred. Wait 2+ hours after last meal.
8-16 week cycles.
Take our free assessment to get personalized recommendations based on your health goals, current stack, and biomarkers.
Get Your Free Protocol →or take the assessment →