Comparison
GHK-Cu vs NMN
Side-by-side of GHK-Cu and NMN. 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.
NMN
NMN supplements are oral nicotinamide mononucleotide capsules sold for longevity, energy, and metabolic health. They raise plasma NAD+ 30-90% at 250-1000.
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
NMN
- •Plasma NAD+ rises 30-90% at 250-1000 mg/day across human PK studies
- •Tissue NAD+ rise is inconsistent across human trials (Yoshino 2021, Igarashi 2022)
- •No human trials measure hard endpoints (mortality, CV events, cancer); evidence is biomarker-only
- •Most trials cluster at 250-500 mg/day; dose-response above 250 mg/day is poorly characterized
- •FDA position contested; widely sold as supplement but with regulatory uncertainty
- •Marketing claims for fertility and longevity outrun the human trial evidence substantially
Side-by-side
| Attribute | GHK-Cu | NMN |
|---|---|---|
| Category | peptide | supplement |
| Also known as | Copper Peptide, Glycyl-L-histidyl-L-lysine copper, GHK | nicotinamide mononucleotide, beta-NMN |
| Half-life (hr) ↗ | 0.5 | 4 |
| Typical dose (mg) ↗ | 2 | 250 |
| Dosing frequency | daily | 1x daily, often morning |
| Routes | topical, subcutaneous | oral, sublingual |
| Onset (hr) | 24 | 1 |
| Peak (hr) | 168 | 3 |
| Molecular weight | 340.85 | 334.22 |
| Molecular formula | C14H24N6O4 (GHK alone); C14H22CuN6O4 with Cu(II) | C11H15N2O8P |
| 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. | Direct precursor in the NAD+ salvage pathway; converted to NAD+ by NMNAT enzymes in essentially every tissue. Raised NAD+ supports sirtuin and PARP enzyme activity. |
| Legal status | Topical cosmetics legal in most jurisdictions; injectable form not FDA approved for any indication; research-use-only grey market | Contested in US (FDA position 2022); widely sold as supplement; broadly available in EU, UK, Asia |
| WADA status | allowed | allowed |
| DEA / Rx | Topical OTC (cosmetic); injectable not FDA approved; research-chemical status | Not scheduled |
| Pregnancy | Insufficient data; topical use likely low-risk; injectable not recommended | Insufficient data; precautionary avoidance |
| CAS | 49557-75-7 | 1094-61-7 |
| PubChem CID | 73587 | 14180 |
| Wikidata | Q3104638 | Q418972 |
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)
NMN
Common side effects
- mild GI upset (rare)
- occasional headache
- flushing (rare)
Contraindications
- pregnancy and lactation (precautionary, no data)
- active cancer (theoretical concern, not evidence-based)
Interactions
- metformin: no clinically significant interaction documented; both modulate metabolism through different mechanisms(minor)
- chemotherapy agents: theoretical concern about supporting cancer cell proliferation; coordinate with oncology team(moderate)
- CD38 inhibitors: would amplify NMN-induced NAD+ rise; not clinically relevant for most users(minor)
Which Should You Take?
NMN comes out ahead for most readers on the criteria we weight: 3 catalogued goals, Contested in US (FDA position 2022); widely sold as supplement; broadly available in EU, UK, Asia, 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 energy and stamina, pick NMN.
- → If your priority is metabolic health and glucose control, pick NMN.
Edge case: If you cannot self-administer injections, NMN is the only oral option in this pair.
Default choice: NMN. 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 NMN?
GHK-Cu and NMN differ in category (peptide vs supplement), mechanism, and typical dosing. See the side-by-side table for full details.
Which has a longer half-life, GHK-Cu or NMN?
GHK-Cu half-life is 0.5 hours; NMN half-life is 4 hours.
Can you stack GHK-Cu with NMN?
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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