Comparison
GHK-Cu vs Rapamycin
Side-by-side of GHK-Cu and Rapamycin. 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.
Rapamycin
Rapamycin for longevity: sirolimus, an mTOR inhibitor with ITP mouse lifespan data. Off-label geroprotective dosing remains investigational.
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
Rapamycin
- •Inhibits mTORC1 signaling by binding FKBP12, reducing protein synthesis and relieving autophagy suppression
- •ITP mouse program reproduced lifespan extension of ~10 to 25% across multiple genetic backgrounds and sexes
- •Mannick trials showed improved influenza vaccine response in elderly adults using analogs of rapamycin
- •PEARL human trial reported acceptable safety at 5 to 10 mg weekly with some functional and lean-mass signals
- •Common dose-limiting adverse effects include stomatitis, acne-like rash, and mildly elevated lipid markers
- •CYP3A4 substrate: grapefruit, ketoconazole, and clarithromycin substantially raise rapamycin exposure
Side-by-side
| Attribute | GHK-Cu | Rapamycin |
|---|---|---|
| Category | peptide | pharmaceutical |
| Also known as | Copper Peptide, Glycyl-L-histidyl-L-lysine copper, GHK | Sirolimus, Rapamune |
| Half-life (hr) ↗ | 0.5 | 62 |
| Typical dose (mg) ↗ | 2 | 6 |
| Dosing frequency | daily | weekly (longevity protocols); daily for transplant indication |
| Routes | topical, subcutaneous | oral |
| Onset (hr) | 24 | 1 |
| Peak (hr) | 168 | 2 |
| Molecular weight | 340.85 | 914.17 |
| Molecular formula | C14H24N6O4 (GHK alone); C14H22CuN6O4 with Cu(II) | C51H79NO13 |
| 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. | Binds FKBP12, and the resulting complex inhibits mTORC1, reducing protein synthesis and autophagy suppression downstream of nutrient and growth-factor signaling. |
| Legal status | Topical cosmetics legal in most jurisdictions; injectable form not FDA approved for any indication; research-use-only grey market | Prescription only (off-label for longevity) |
| WADA status | allowed | allowed |
| DEA / Rx | Topical OTC (cosmetic); injectable not FDA approved; research-chemical status | Rx only (not a controlled substance) |
| Pregnancy | Insufficient data; topical use likely low-risk; injectable not recommended | Not recommended |
| CAS | 49557-75-7 | 53123-88-9 |
| PubChem CID | 73587 | 5284616 |
| Wikidata | Q3104638 | Q410174 |
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)
Rapamycin
Common side effects
- mouth ulcers (stomatitis)
- acne-like rash
- GI upset
- altered lipid panel
- delayed wound healing
Contraindications
- active infection
- severe hepatic impairment
- planned surgery (delayed wound healing)
- pregnancy
- live vaccines within dosing window
Interactions
- strong CYP3A4 inhibitors (ketoconazole, clarithromycin, grapefruit): substantially raises rapamycin levels, toxicity risk(major)
- strong CYP3A4 inducers (rifampin, St John's wort): lowers rapamycin levels, reduced effect(major)
- ACE inhibitors: increased risk of angioedema(moderate)
- live vaccines: reduced vaccine efficacy due to immunosuppression(major)
Which Should You Take?
Rapamycin comes out ahead for most readers on the criteria we weight: 2 catalogued goals, prescription-only, oral dosing, with a Tier-A outcome catalogued. GHK-Cu 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 immune support, pick Rapamycin.
Edge case: If you cannot self-administer injections, Rapamycin is the only oral option in this pair.
Default choice: Rapamycin. Wider use case, a Tier-A evidence outcome catalogued, and broader goal coverage. Reach for GHK-Cu 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 Rapamycin?
GHK-Cu and Rapamycin differ in category (peptide vs pharmaceutical), mechanism, and typical dosing. See the side-by-side table for full details.
Which has a longer half-life, GHK-Cu or Rapamycin?
GHK-Cu half-life is 0.5 hours; Rapamycin half-life is 62 hours.
Can you stack GHK-Cu with Rapamycin?
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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