Comparison
GHK-Cu vs Magnesium Glycinate
Side-by-side of GHK-Cu and Magnesium Glycinate. 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.
Magnesium Glycinate
Magnesium glycinate supplement guide: chelated bisglycinate form, 200 to 400 mg dosage, sleep architecture benefits, low GI side effects, glycine co-effect.
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
Magnesium Glycinate
- •Shortens sleep onset latency in older adults and in deficient populations supplementing 200 to 400 mg elemental Mg
- •Improves subjective sleep quality scores (PSQI, ISI) modestly versus placebo over 4 to 8 weeks
- •Reduces nocturnal leg cramps and exercise-induced muscle cramping in some controlled trials
- •Lowers self-reported anxiety in mild-to-moderate cases, with smaller effect than first-line pharmacotherapy
- •Glycinate form delivers fewer GI side effects than oxide or citrate at equivalent elemental doses
- •Insufficient as a stand-alone hypertension treatment; small adjunctive blood-pressure reductions only
Side-by-side
| Attribute | GHK-Cu | Magnesium Glycinate |
|---|---|---|
| Category | peptide | supplement |
| Also known as | Copper Peptide, Glycyl-L-histidyl-L-lysine copper, GHK | magnesium bisglycinate |
| Half-life (hr) ↗ | 0.5 | 5 |
| Typical dose (mg) ↗ | 2 | 300 |
| Dosing frequency | daily | daily (often evening) |
| Routes | topical, subcutaneous | oral |
| Onset (hr) | 24 | 1 |
| Peak (hr) | 168 | - |
| Molecular weight | 340.85 | - |
| Molecular formula | C14H24N6O4 (GHK alone); C14H22CuN6O4 with Cu(II) | - |
| 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. | Magnesium acts as a cofactor for 300+ enzymes and as a voltage-dependent antagonist at NMDA receptors; glycine serves as an inhibitory neurotransmitter and co-agonist at glycine receptors. |
| Legal status | Topical cosmetics legal in most jurisdictions; injectable form not FDA approved for any indication; research-use-only grey market | Dietary supplement |
| WADA status | allowed | allowed |
| DEA / Rx | Topical OTC (cosmetic); injectable not FDA approved; research-chemical status | OTC supplement |
| Pregnancy | Insufficient data; topical use likely low-risk; injectable not recommended | Generally considered acceptable at RDA doses; consult clinician |
| CAS | 49557-75-7 | 14783-68-7 |
| PubChem CID | 73587 | 84645 |
| Wikidata | Q3104638 | - |
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)
Magnesium Glycinate
Common side effects
- mild GI upset at high doses
- loose stools (dose-dependent, less than with oxide/citrate forms)
Contraindications
- severe renal impairment
- myasthenia gravis
- heart block
Interactions
- tetracycline and fluoroquinolone antibiotics: magnesium chelates antibiotic, reducing absorption; separate by 2+ hours(moderate)
- bisphosphonates: reduced absorption of bisphosphonate(moderate)
- potassium-sparing diuretics: possible hypermagnesemia in renal impairment(moderate)
Which Should You Take?
Magnesium Glycinate comes out ahead for most readers on the criteria we weight: 3 catalogued goals, OTC dietary supplement, 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 sleep onset or sleep quality, pick Magnesium Glycinate.
- → If your priority is post-training recovery, pick Magnesium Glycinate.
Edge case: If you want to avoid research-only / gray-market sourcing, Magnesium Glycinate is the more accessible choice.
Default choice: Magnesium Glycinate. Lower friction to source, 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 Magnesium Glycinate?
GHK-Cu and Magnesium Glycinate 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 Magnesium Glycinate?
GHK-Cu half-life is 0.5 hours; Magnesium Glycinate half-life is 5 hours.
Can you stack GHK-Cu with Magnesium Glycinate?
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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