Comparison
GHK-Cu vs N-Acetyl Cysteine
Side-by-side of GHK-Cu and N-Acetyl Cysteine. 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.
N-Acetyl Cysteine
NAC supplement benefits cover glutathione synthesis, liver and antioxidant support, and hangover recovery. Evidence strongest at 1200-2400 mg/day.
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
N-Acetyl Cysteine
- •Replenishes intracellular glutathione by supplying cysteine, the rate-limiting amino acid for synthesis
- •First-line antidote for acetaminophen toxicity, restoring hepatic glutathione before fulminant injury occurs
- •Reduces sputum viscosity in chronic bronchitis and COPD at 600 to 1200 mg/day over months
- •Modest symptom reductions in OCD and trichotillomania at 1200 to 2400 mg/day across small RCTs
- •Mixed evidence for psychiatric adjunct use in bipolar depression and schizophrenia negative symptoms
- •Inhaled forms can trigger bronchospasm in active asthma; oral use is the standard biohacker route
Side-by-side
| Attribute | GHK-Cu | N-Acetyl Cysteine |
|---|---|---|
| Category | peptide | supplement |
| Also known as | Copper Peptide, Glycyl-L-histidyl-L-lysine copper, GHK | NAC |
| Half-life (hr) ↗ | 0.5 | 5.6 |
| Typical dose (mg) ↗ | 2 | 1200 |
| Dosing frequency | daily | 1 to 3 times daily, split dosing preferred |
| Routes | topical, subcutaneous | oral, iv |
| Onset (hr) | 24 | 1 |
| Peak (hr) | 168 | 2 |
| Molecular weight | 340.85 | 163.19 |
| Molecular formula | C14H24N6O4 (GHK alone); C14H22CuN6O4 with Cu(II) | C5H9NO3S |
| 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. | Deacetylated to cysteine, the rate-limiting precursor for glutathione synthesis; also directly scavenges reactive oxygen species and modulates glutamate signaling. |
| Legal status | Topical cosmetics legal in most jurisdictions; injectable form not FDA approved for any indication; research-use-only grey market | OTC in most jurisdictions; restricted periods in US history (FDA reclassified 2022) |
| WADA status | allowed | allowed |
| DEA / Rx | Topical OTC (cosmetic); injectable not FDA approved; research-chemical status | OTC supplement (US, post-2022); Rx indications also exist (acetaminophen overdose, mucolytic) |
| Pregnancy | Insufficient data; topical use likely low-risk; injectable not recommended | Used clinically in pregnancy for specific indications; consult clinician |
| CAS | 49557-75-7 | 616-91-1 |
| PubChem CID | 73587 | 12035 |
| Wikidata | Q3104638 | Q413299 |
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)
N-Acetyl Cysteine
Common side effects
- sulfur-like taste or odor
- nausea
- flatulence
- diarrhea
Contraindications
- active asthma attack (inhaled form can trigger bronchospasm)
- known NAC hypersensitivity
Interactions
- nitroglycerin: potentiates vasodilation, risk of hypotension and headache(moderate)
- activated charcoal: reduces NAC absorption when used for acetaminophen overdose(moderate)
- anticoagulants: theoretical additive antiplatelet effect at high doses(minor)
Which Should You Take?
N-Acetyl Cysteine comes out ahead for most readers on the criteria we weight: 3 catalogued goals, OTC, 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 post-training recovery, pick N-Acetyl Cysteine.
- → If your priority is liver function, pick N-Acetyl Cysteine.
Edge case: If you want to avoid research-only / gray-market sourcing, N-Acetyl Cysteine is the more accessible choice.
Default choice: N-Acetyl Cysteine. 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 N-Acetyl Cysteine?
GHK-Cu and N-Acetyl Cysteine 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 N-Acetyl Cysteine?
GHK-Cu half-life is 0.5 hours; N-Acetyl Cysteine half-life is 5.6 hours.
Can you stack GHK-Cu with N-Acetyl Cysteine?
Stack compatibility depends on mechanism overlap, legal status, and individual response. Check each compound page for specific interactions and contraindications before combining.
Go deeper