Comparison
GHK-Cu vs Testosterone
Side-by-side of GHK-Cu and Testosterone. 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.
Testosterone
Testosterone replacement therapy for hypogonadism: TRAVERSE 2023 cardiovascular data, cypionate dosing, body composition gains, Schedule III status.
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
Testosterone
- •Primary androgen; FDA approved for hypogonadism with confirmed deficiency and symptoms
- •Testosterone Trials (2016) showed sexual function and bone density improvements in older hypogonadal men
- •TRAVERSE 2023 (n=5,246) found non-inferiority on MACE versus placebo, with higher AF and PE rates
- •Schedule III controlled substance in US; WADA banned in sport
- •Aromatizes to estradiol; converts to DHT via 5-alpha reductase; both metabolites matter clinically
- •Erythrocytosis (HCT above 54%) affects 5 to 25% of users and is the most common dose-limiting effect
Side-by-side
| Attribute | GHK-Cu | Testosterone |
|---|---|---|
| Category | peptide | hormone |
| Also known as | Copper Peptide, Glycyl-L-histidyl-L-lysine copper, GHK | TRT, testosterone replacement therapy, testosterone cypionate, testosterone enanthate, Androgel, Testim |
| Half-life (hr) ↗ | 0.5 | 192 |
| Typical dose (mg) ↗ | 2 | 150 |
| Dosing frequency | daily | weekly to twice-weekly (cypionate/enanthate IM or SC); daily (topical, oral); every 3 to 6 months (pellet) |
| Routes | topical, subcutaneous | intramuscular, subcutaneous, topical, buccal, subcutaneous (pellet), oral |
| Onset (hr) | 24 | 24 |
| Peak (hr) | 168 | 72 |
| Molecular weight | 340.85 | 288.42 |
| Molecular formula | C14H24N6O4 (GHK alone); C14H22CuN6O4 with Cu(II) | C19H28O2 |
| 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. | Androgen receptor agonist driving anabolic gene transcription in muscle, bone, brain, and androgen-sensitive tissue. Aromatized to estradiol and 5-alpha-reduced to DHT, both with distinct downstream effects. |
| Legal status | Topical cosmetics legal in most jurisdictions; injectable form not FDA approved for any indication; research-use-only grey market | Schedule III controlled substance (US); WADA banned |
| WADA status | allowed | banned |
| DEA / Rx | Topical OTC (cosmetic); injectable not FDA approved; research-chemical status | Schedule III |
| Pregnancy | Insufficient data; topical use likely low-risk; injectable not recommended | Category X; contraindicated in pregnancy (virilizing effect on female fetus) |
| CAS | 49557-75-7 | 58-22-0 |
| PubChem CID | 73587 | 6013 |
| Wikidata | Q3104638 | Q150726 |
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)
Testosterone
Common side effects
- erythrocytosis
- acne
- oily skin
- fluid retention
- increased body hair
- fertility suppression
- injection-site reactions
Contraindications
- active prostate cancer
- active breast cancer
- untreated severe sleep apnea
- untreated severe BPH
- uncontrolled heart failure
- polycythemia at baseline
Interactions
- warfarin: may potentiate anticoagulant effect; monitor INR(moderate)
- insulin: may improve insulin sensitivity; monitor glucose in diabetics(moderate)
- 5-alpha reductase inhibitors (finasteride): blocks DHT conversion; reduces some androgen effects(moderate)
- aromatase inhibitors (anastrozole): lowers estradiol; risk of over-suppression(moderate)
Which Should You Take?
Testosterone comes out ahead for most readers on the criteria we weight: 3 catalogued goals, controlled substance, 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 hormonal optimization, pick Testosterone.
- → If your priority is sexual function, pick Testosterone.
Edge case: If you cannot self-administer injections, Testosterone is the only oral option in this pair.
Default choice: Testosterone. 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 Testosterone?
GHK-Cu and Testosterone differ in category (peptide vs hormone), mechanism, and typical dosing. See the side-by-side table for full details.
Which has a longer half-life, GHK-Cu or Testosterone?
GHK-Cu half-life is 0.5 hours; Testosterone half-life is 192 hours.
Can you stack GHK-Cu with Testosterone?
Stack compatibility depends on mechanism overlap, legal status, and individual response. Check each compound page for specific interactions and contraindications before combining.
Go deeper