Comparison
GHRP-6 vs Thymosin Alpha-1
Side-by-side of GHRP-6 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.
GHRP-6
First-generation hexapeptide ghrelin-receptor agonist. Pioneered the GHS-R1a pathway in the 1980s. Produces the strongest hunger response among GHRPs and a mo.
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
GHRP-6
- •First-generation hexapeptide ghrelin-receptor agonist; foundational to the GHRP class
- •Strongest appetite stimulation of any synthetic GHRP at equivalent GH doses
- •Produces measurable cortisol and prolactin rise alongside the GH pulse
- •Anecdotal protocols use 100 to 200 mcg subcutaneously 2 to 3 times daily on an empty stomach
- •Largely superseded by ipamorelin (cleaner profile) and GHRP-2 (stronger pulse) for body-composition use
- •Banned by WADA under S2; detection methods validated in accredited labs
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 | GHRP-6 | Thymosin Alpha-1 |
|---|---|---|
| Category | peptide | peptide |
| Also known as | Growth Hormone Releasing Peptide 6, SKF-110679, Histidyl-D-Tryptophyl-Alanyl-Tryptophyl-D-Phenylalanyl-Lysinamide | Talpha1, Ta1, Zadaxin, Thymalfasin |
| Half-life (hr) ↗ | 0.5 | 2 |
| Typical dose (mg) ↗ | 0.1 | 1.6 |
| Dosing frequency | 2-3x daily | 2x weekly |
| Routes | subcutaneous, intravenous | subcutaneous, intramuscular |
| Onset (hr) | 0.25 | 24 |
| Peak (hr) | 0.5 | 168 |
| Molecular weight | 872.44 | 3108.32 |
| Molecular formula | C46H56N12O6 | C129H215N33O55 |
| Mechanism | Hexapeptide agonist of GHS-R1a (ghrelin receptor). Suppresses hypothalamic somatostatin and stimulates pituitary somatotrophs, with strong central NPY/AgRP appetite signaling and modest cortisol and prolactin release. | 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 | Not FDA approved; research-use-only grey market; banned by WADA | 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 | banned | unknown |
| DEA / Rx | Not scheduled (research chemical) | Rx only via international approval or US compounding (no controlled-substance schedule) |
| Pregnancy | Insufficient data; not recommended | Not recommended; insufficient data |
| CAS | 87616-84-0 | 62304-98-7 |
| PubChem CID | 9919072 | 16130571 |
| Wikidata | Q5519921 | Q913854 |
Safety profile
GHRP-6
Common side effects
- intense hunger
- water retention
- vivid dreams
- head pressure or flushing
- tingling at injection site
- transient lethargy
Contraindications
- pregnancy
- active malignancy
- history of pituitary tumor
- uncontrolled diabetes
- prolactin sensitivity
Interactions
- CJC-1295: synergistic GH release; commonly co-administered(minor)
- sermorelin: additive GH release via parallel GHRH and ghrelin pathways(minor)
- insulin: sustained GH can blunt insulin sensitivity over weeks(moderate)
- corticosteroids: blunt GH response and amplify cortisol load(moderate)
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. GHRP-6 is the right call when one of the conditionals below applies.
- → If your priority is growth-hormone axis, pick GHRP-6.
- → If your priority is appetite regulation, pick GHRP-6.
- → If your priority is immune support, pick Thymosin Alpha-1.
- → If your priority is antiviral action, pick Thymosin Alpha-1.
Edge case: Half-lives differ materially (GHRP-6 ~0.5 hr vs Thymosin Alpha-1 ~2 hr). Thymosin Alpha-1 reaches steady state faster; GHRP-6 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 GHRP-6 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 GHRP-6 and Thymosin Alpha-1?
GHRP-6 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, GHRP-6 or Thymosin Alpha-1?
GHRP-6 half-life is 0.5 hours; Thymosin Alpha-1 half-life is 2 hours.
Can you stack GHRP-6 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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