Comparison
GHK-Cu vs GHRP-2
Side-by-side of GHK-Cu and GHRP-2. Every row below is pulled from the compound schema and will update as our data grows. For deeper reads, follow through to each compound page.
GHK-Cu
GHK-Cu peptide (glycyl-L-histidyl-L-lysine copper) is a topical copper peptide. Trials show fine-line and wound-healing gains; injectable longevity claims rem.
GHRP-2
GHRP-2 peptide (pralmorelin, KP-102) is a synthetic hexapeptide ghrelin-receptor agonist that triggers pulsatile growth hormone release via the pituitary.
Effects at a glance
GHK-Cu
- •Endogenous tripeptide that binds copper(II); plasma levels decline ~60% from age 20 to 60
- •Topical RCTs show improvement in skin firmness, fine lines, and barrier function over 12 weeks
- •Wound-healing models report accelerated re-epithelialization in diabetic and aged skin
- •Pickart gene-expression analyses show reset of >4000 genes toward a younger expression profile in cell culture
- •Anecdotal subcutaneous longevity protocols use 1 to 3 mg daily; no human longevity RCTs exist
- •Hair-growth claims rest on small open-label trials and topical scalp formulations
GHRP-2
- •Hexapeptide ghrelin-receptor agonist that stimulates pulsatile GH release within 15 to 30 minutes
- •Strongest appetite signal among GHRPs at standard doses; centrally mediated via NPY/AgRP
- •Produces measurable cortisol and prolactin rise (more than ipamorelin, less than GHRP-6)
- •Approved in Japan as pralmorelin for GH-deficiency diagnostic provocation; not FDA approved
- •Anecdotal protocols use 100 to 300 mcg subcutaneously 2 to 3 times daily on an empty stomach
- •Banned by WADA under S2; detection methods validated in accredited labs
Side-by-side
| Attribute | GHK-Cu | GHRP-2 |
|---|---|---|
| Category | peptide | peptide |
| Also known as | Copper Peptide, Glycyl-L-histidyl-L-lysine copper, GHK | Growth Hormone Releasing Peptide 2, Pralmorelin, KP-102, GPA-748 |
| Half-life (hr) ↗ | 0.5 | 0.5 |
| Typical dose (mg) ↗ | 2 | 0.1 |
| Dosing frequency | daily | 2-3x daily |
| Routes | topical, subcutaneous | subcutaneous, intranasal, intravenous |
| Onset (hr) | 24 | 0.25 |
| Peak (hr) | 168 | 0.5 |
| Molecular weight | 340.85 | 817.97 |
| Molecular formula | C14H24N6O4 (GHK alone); C14H22CuN6O4 with Cu(II) | C45H55N9O6 |
| Mechanism | Tripeptide that chelates Cu(II) and delivers it to copper-dependent enzymes (lysyl oxidase, superoxide dismutase). Modulates expression of >4000 genes toward a younger profile in fibroblast culture, including upregulation of decorin and downregulation of pro-inflammatory cytokines. | Hexapeptide agonist of the growth-hormone secretagogue receptor (GHS-R1a). Suppresses hypothalamic somatostatin tone and stimulates pituitary somatotrophs, producing a pulsatile GH release with secondary cortisol, prolactin, and ACTH elevation. |
| Legal status | Topical cosmetics legal in most jurisdictions; injectable form not FDA approved for any indication; research-use-only grey market | Not FDA approved; approved in Japan as pralmorelin (diagnostic); research-use-only grey market in US/EU; banned by WADA |
| WADA status | allowed | banned |
| DEA / Rx | Topical OTC (cosmetic); injectable not FDA approved; research-chemical status | Not scheduled in US (research chemical); approved diagnostic in Japan |
| Pregnancy | Insufficient data; topical use likely low-risk; injectable not recommended | Insufficient data; not recommended |
| CAS | 49557-75-7 | 158861-67-7 |
| PubChem CID | 73587 | 9919072 |
| Wikidata | Q3104638 | Q7235681 |
Safety profile
GHK-Cu
Common side effects
- mild erythema at topical site
- transient itch
- blue-green discoloration of injection site (copper)
- rare contact dermatitis
Contraindications
- copper allergy
- Wilson disease
- open wound near injection site (caution)
- pregnancy (no data)
Interactions
- topical retinoids: additive irritation; alternate days or apply at different times(minor)
- topical vitamin C (ascorbic acid): ascorbate reduces Cu(II) to Cu(I), which can destabilize the GHK-Cu complex; separate by 30 minutes(minor)
GHRP-2
Common side effects
- acute hunger
- head pressure or flushing
- water retention
- vivid dreams
- tingling at injection site
- transient lethargy
Contraindications
- pregnancy
- active malignancy
- history of pituitary tumor
- uncontrolled diabetes
- severe insulin resistance
Interactions
- CJC-1295: synergistic GH release; commonly co-administered for larger pulse(minor)
- sermorelin: additive GH release via parallel GHRH and ghrelin pathways(minor)
- insulin: sustained GH can blunt insulin sensitivity over weeks(moderate)
- corticosteroids: blunt GH response and amplify cortisol load(moderate)
Which Should You Take?
GHK-Cu comes out ahead for most readers on the criteria we weight: 4 catalogued goals, research-only / gray-market sourcing, with a Tier-B outcome catalogued. GHRP-2 is the right call when one of the conditionals below applies.
- → If your priority is skin health, pick GHK-Cu.
- → If your priority is wound healing, pick GHK-Cu.
- → If your priority is growth-hormone axis, pick GHRP-2.
- → If your priority is post-training recovery, pick GHRP-2.
Default choice: GHK-Cu. Wider use case, and broader goal coverage. Reach for GHRP-2 only if your priority sits squarely in the goals it owns above.
This verdict is generated from each compound's schema (goals, legal status, evidence outcomes, dosing route). It updates automatically as our compound data evolves; the deeper read sits on each individual compound page.
Common questions
What is the difference between GHK-Cu and GHRP-2?
GHK-Cu and GHRP-2 differ in category (peptide vs peptide), mechanism, and typical dosing. See the side-by-side table for full details.
Which has a longer half-life, GHK-Cu or GHRP-2?
GHK-Cu half-life is 0.5 hours; GHRP-2 half-life is 0.5 hours.
Can you stack GHK-Cu with GHRP-2?
Stack compatibility depends on mechanism overlap, legal status, and individual response. Check each compound page for specific interactions and contraindications before combining.
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