Comparison
Citicoline vs GHK-Cu
Side-by-side of Citicoline and GHK-Cu. 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.
Citicoline
Citicoline supplement profile: CDP-choline as a phosphatidylcholine precursor, Cognizin dosing 250-2000 mg, cognition trials, stroke recovery evidence.
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.
Effects at a glance
Citicoline
- •Choline donor and phosphatidylcholine precursor; oral bioavailability roughly 99%
- •Standard prescription medication for stroke recovery and vascular cognitive impairment in much of the world
- •Healthy-adult cognitive trials (Cognizin) report small gains in attention and working memory at 250 to 500 mg/day
- •ICTUS trial (n=2,298) was negative on stroke recovery in the modern thrombolysis era
- •Lower per-gram choline content than alpha-GPC (~18% vs ~40%), meaning smaller TMAO load at equivalent dose
- •Long uridine half-life (~56 hours) supports once or twice daily dosing
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
Side-by-side
| Attribute | Citicoline | GHK-Cu |
|---|---|---|
| Category | supplement | peptide |
| Also known as | CDP-choline, cytidine 5'-diphosphocholine, Cognizin | Copper Peptide, Glycyl-L-histidyl-L-lysine copper, GHK |
| Half-life (hr) ↗ | 56 | 0.5 |
| Typical dose (mg) ↗ | 500 | 2 |
| Dosing frequency | 1 to 2 times daily | daily |
| Routes | oral, intravenous | topical, subcutaneous |
| Onset (hr) | 1 | 24 |
| Peak (hr) | 2 | 168 |
| Molecular weight | 488.32 | 340.85 |
| Molecular formula | C14H26N4O11P2 | C14H24N6O4 (GHK alone); C14H22CuN6O4 with Cu(II) |
| Mechanism | Hydrolyzed to cytidine and choline after absorption; both cross the blood-brain barrier and are recombined intracellularly to reform CDP-choline, supporting phosphatidylcholine synthesis and acetylcholine production. | 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. |
| Legal status | Dietary supplement (US, Cognizin GRAS); prescription medication in most of the world | Topical cosmetics legal in most jurisdictions; injectable form not FDA approved for any indication; research-use-only grey market |
| WADA status | allowed | allowed |
| DEA / Rx | OTC supplement (US); Rx in most of the world | Topical OTC (cosmetic); injectable not FDA approved; research-chemical status |
| Pregnancy | Insufficient data for routine use | Insufficient data; topical use likely low-risk; injectable not recommended |
| CAS | 987-78-0 | 49557-75-7 |
| PubChem CID | 13804 | 73587 |
| Wikidata | Q411470 | Q3104638 |
Safety profile
Citicoline
Common side effects
- mild GI upset
- headache
- restlessness
- occasional insomnia with evening dosing
Contraindications
- concurrent strong anticholinergic therapy
- established cardiovascular disease (TMAO concern, smaller than alpha-GPC)
Interactions
- anticholinergic medications: partial mutual antagonism(minor)
- cholinesterase inhibitors: additive cholinergic effect(minor)
- antimetabolite chemotherapy (5-FU): theoretical cytidine pathway interaction(minor)
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)
Which Should You Take?
Citicoline comes out ahead for most readers on the criteria we weight: 3 catalogued goals, OTC dietary supplement, oral dosing, with a Tier-B outcome catalogued. GHK-Cu is the right call when one of the conditionals below applies.
- → If your priority is focus or working memory, pick Citicoline.
- → If your priority is stroke recovery, pick Citicoline.
- → If your priority is skin health, pick GHK-Cu.
- → If your priority is wound healing, pick GHK-Cu.
Edge case: If you want to avoid research-only / gray-market sourcing, Citicoline is the more accessible choice.
Default choice: Citicoline. Lower friction to source, 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 Citicoline and GHK-Cu?
Citicoline and GHK-Cu differ in category (supplement vs peptide), mechanism, and typical dosing. See the side-by-side table for full details.
Which has a longer half-life, Citicoline or GHK-Cu?
Citicoline half-life is 56 hours; GHK-Cu half-life is 0.5 hours.
Can you stack Citicoline with GHK-Cu?
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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