Comparison
AOD-9604 vs Thymosin Alpha-1
Side-by-side of AOD-9604 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.
AOD-9604
AOD 9604 peptide: 16-amino-acid hGH fragment 176-191. Preclinical lipolytic activity, phase 2 obesity trial showed no weight loss vs placebo.
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
AOD-9604
- •Modified 16-amino-acid synthetic fragment of human growth hormone (residues 176-191)
- •Preclinical models show lipolytic activity in adipose tissue without GH-axis growth effects
- •Phase 2 obesity trial (Heffernan 2001) showed no significant weight-loss difference versus placebo
- •Anecdotal protocols use 250 to 500 mcg subcutaneously daily on an empty stomach
- •No FDA approval; the obesity drug development program was discontinued in 2007
- •Granted GRAS status in some jurisdictions for compounded use; not validated for fat loss in humans
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 | AOD-9604 | Thymosin Alpha-1 |
|---|---|---|
| Category | peptide | peptide |
| Also known as | hGH fragment 176-191, Human Growth Hormone Fragment 176-191 | Talpha1, Ta1, Zadaxin, Thymalfasin |
| Half-life (hr) ↗ | 0.5 | 2 |
| Typical dose (mg) ↗ | 0.3 | 1.6 |
| Dosing frequency | daily | 2x weekly |
| Routes | subcutaneous | subcutaneous, intramuscular |
| Onset (hr) | 1 | 24 |
| Peak (hr) | 2 | 168 |
| Molecular weight | 1815.17 | 3108.32 |
| Molecular formula | C78H125N23O23S2 | C129H215N33O55 |
| Mechanism | Modified C-terminal fragment of human growth hormone proposed to stimulate beta-3 adrenergic receptor signaling in adipocytes, increasing lipolysis and fatty-acid oxidation without engaging the GH receptor or activating IGF-1. | 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 in most jurisdictions | 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 | unknown | unknown |
| DEA / Rx | Not FDA approved; not scheduled; research-chemical status | Rx only via international approval or US compounding (no controlled-substance schedule) |
| Pregnancy | Insufficient data; not recommended | Not recommended; insufficient data |
| CAS | 221231-10-3 | 62304-98-7 |
| PubChem CID | 71300630 | 16130571 |
| Wikidata | Q4654106 | Q913854 |
Safety profile
AOD-9604
Common side effects
- injection-site reactions
- transient mild headache (anecdotal)
- minimal in clinical trials
Contraindications
- pregnancy
- lactation
- no established human safety profile for chronic use
Interactions
- beta-blockers: theoretical antagonism of beta-3 adrenergic lipolytic signaling(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. AOD-9604 is the right call when one of the conditionals below applies.
- → If your priority is fat loss, pick AOD-9604.
- → If your priority is body composition, pick AOD-9604.
- → 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 (AOD-9604 ~0.5 hr vs Thymosin Alpha-1 ~2 hr). Thymosin Alpha-1 reaches steady state faster; AOD-9604 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 AOD-9604 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 AOD-9604 and Thymosin Alpha-1?
AOD-9604 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, AOD-9604 or Thymosin Alpha-1?
AOD-9604 half-life is 0.5 hours; Thymosin Alpha-1 half-life is 2 hours.
Can you stack AOD-9604 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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