Comparison
GHK-Cu vs Thymosin Alpha-1
Side-by-side of GHK-Cu and Thymosin Alpha-1. 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.
Thymosin Alpha-1
Thymosin alpha-1 peptide (Zadaxin, thymalfasin): 28-amino-acid TA1 immunomodulator. Dosing, T-cell effects, hepatitis B and HCV adjunct evidence.
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
Thymosin Alpha-1
- •28-amino-acid synthetic peptide identical to thymic-derived immunomodulator
- •Approved in over 35 countries as Zadaxin for hepatitis B, hepatitis C adjunct, and immune support
- •Not FDA approved in US; compounded by 503A/503B pharmacies for off-label immune support
- •Modulates T-cell maturation, NK activity, and Th1 polarization in immunocompromised states
- •Standard label dose: 1.6 mg subcutaneously twice weekly
- •Cleanest safety profile in the peptide class with hundreds of regulated trials behind it
Side-by-side
| Attribute | GHK-Cu | Thymosin Alpha-1 |
|---|---|---|
| Category | peptide | peptide |
| Also known as | Copper Peptide, Glycyl-L-histidyl-L-lysine copper, GHK | Talpha1, Ta1, Zadaxin, Thymalfasin |
| Half-life (hr) ↗ | 0.5 | 2 |
| Typical dose (mg) ↗ | 2 | 1.6 |
| Dosing frequency | daily | 2x weekly |
| Routes | topical, subcutaneous | subcutaneous, intramuscular |
| Onset (hr) | 24 | 24 |
| Peak (hr) | 168 | 168 |
| Molecular weight | 340.85 | 3108.32 |
| Molecular formula | C14H24N6O4 (GHK alone); C14H22CuN6O4 with Cu(II) | C129H215N33O55 |
| 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. | Synthetic peptide modulator of innate and adaptive immunity. Promotes T-cell maturation and CD4/CD8 production, modulates Th1/Th2 balance, stimulates NK cell activity, and modulates TLR2/TLR9 signaling in dendritic cells. |
| Legal status | Topical cosmetics legal in most jurisdictions; injectable form not FDA approved for any indication; research-use-only grey market | Approved in 35+ countries as Zadaxin (hepatitis B, hepatitis C adjunct, immune support); not FDA approved in US; compounded by 503A/503B pharmacies for off-label use; not on WADA Prohibited List |
| WADA status | allowed | unknown |
| DEA / Rx | Topical OTC (cosmetic); injectable not FDA approved; research-chemical status | Rx only via international approval or US compounding (no controlled-substance schedule) |
| Pregnancy | Insufficient data; topical use likely low-risk; injectable not recommended | Not recommended; insufficient data |
| CAS | 49557-75-7 | 62304-98-7 |
| PubChem CID | 73587 | 16130571 |
| Wikidata | Q3104638 | Q913854 |
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)
Thymosin Alpha-1
Common side effects
- mild injection-site irritation (rare)
- transient mild fatigue (rare)
- occasional headache (rare)
Contraindications
- pregnancy
- lactation
- active organ transplant rejection therapy
- systemic immunosuppression for autoimmune disease (relative)
- severe active autoimmune disease (caution)
Interactions
- interferon-alpha: additive immune effect; used clinically in approved combination protocols(minor)
- calcineurin inhibitors (cyclosporine, tacrolimus): theoretical destabilization of immunosuppression; avoid(major)
- antimetabolites (azathioprine, mycophenolate): theoretical destabilization of immunosuppression; avoid(major)
- vaccine administration: may augment vaccine response in elderly or immunocompromised; coordinate with clinician(minor)
Which Should You Take?
Thymosin Alpha-1 comes out ahead for most readers on the criteria we weight: 3 catalogued goals, Approved in 35+ countries as Zadaxin (hepatitis B, hepatitis C adjunct, immune support); not FDA approved in US; compounded by 503A/503B pharmacies for off-label use; not on WADA Prohibited List, 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 immune support, pick Thymosin Alpha-1.
- → If your priority is post-training recovery, pick Thymosin Alpha-1.
Edge case: Half-lives differ materially (GHK-Cu ~0.5 hr vs Thymosin Alpha-1 ~2 hr). Thymosin Alpha-1 reaches steady state faster; GHK-Cu is easier to dial in if tolerability is uncertain.
Default choice: Thymosin Alpha-1. 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 Thymosin Alpha-1?
GHK-Cu and Thymosin Alpha-1 differ in category (peptide vs peptide), mechanism, and typical dosing. See the side-by-side table for full details.
Which has a longer half-life, GHK-Cu or Thymosin Alpha-1?
GHK-Cu half-life is 0.5 hours; Thymosin Alpha-1 half-life is 2 hours.
Can you stack GHK-Cu with Thymosin Alpha-1?
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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