Thymosin Alpha-1 vs Thymosin Beta-4
A neutral, side-by-side comparison of two healing & recovery peptides — their mechanisms, dosing ranges, administration routes, side effects, and research evidence. For research and educational purposes only.
Thymosin Alpha-1
Thymosin Alpha-1 (Tα1) is a 28-amino acid peptide naturally derived from the thymus gland. It plays a central role in regulating immune function — specifically in the maturation and differentiation of T-cells. Unlike most research peptides, Thymosin Alpha-1 has approved clinical use in multiple countries (China, Italy, and others) for hepatitis B, hepatitis C, and as an immune adjuvant in cancer patients undergoing chemotherapy. In the US it is sold as Zadaxin and used as a research compound.
Full profileThymosin Beta-4
Thymosin Beta-4 (TB4) is the full-length 43-amino acid peptide produced naturally in high concentrations in platelets, wound fluid, and regenerating tissue. It is the parent molecule from which the popular TB-500 research peptide (the 17-23 fragment Ac-LKKTETQ) is derived. TB4 promotes actin polymerization, accelerates wound healing, reduces inflammation, and supports cardiac and neurological repair in preclinical models.
Full profile| Thymosin Alpha-1 | Thymosin Beta-4 | |
|---|---|---|
| Category | Healing & Recovery | Healing & Recovery |
| Also known as | Tα1, Thymalfasin, Zadaxin | TB4, Tβ4, Tβ4 full-length |
| Evidence | Research-stage | Investigational (in trials) |
| Dosing range | 900mcg–3.2mg mg, 2–3 times per week subcutaneously | 500mcg–2000mcg mcg, 2–3x weekly |
| Administration | Subcutaneous injection | Subcutaneous injection, Intramuscular injection, Intravenous (clinical studies only) |
| Key side effects | Generally very well tolerated, Mild injection site reactions (most common), Transient fatigue in initial doses, Flu-like symptoms (rare) | Injection site discomfort (mild), Transient fatigue post-injection, Headache (uncommon), Theoretically may accelerate growth of pre-existing malignant tumors (promotes angiogenesis and cell migration — use with caution) |
| Cited sources | 4 references | 3 references |
Key differences
- Evidence level differs: Thymosin Alpha-1 is research-stage, while Thymosin Beta-4 is investigational (in trials).
- Administration: Thymosin Alpha-1 — Subcutaneous injection; Thymosin Beta-4 — Subcutaneous injection, Intramuscular injection, Intravenous (clinical studies only).
- Dosing units differ: Thymosin Alpha-1 is dosed in mg, Thymosin Beta-4 in mcg — they operate at different scales.
- Frequency: Thymosin Alpha-1 is typically 2–3 times per week subcutaneously; Thymosin Beta-4 is 2–3x weekly.
- Research depth: this profile cites 4 sources for Thymosin Alpha-1 vs 3 for Thymosin Beta-4.
How each works
Thymosin Alpha-1
Extensive human clinical research documents Tα1's immune-modulating effects. It increases T-cell counts, enhances NK cell activity, and promotes Th1 cytokine balance. Multiple randomized trials have shown efficacy in treating chronic hepatitis B and C, reducing infection severity in critically ill patients, and improving outcomes in sepsis. More recent research investigates its role in long COVID immune dysregulation. It is considered one of the best-studied peptides in immunology.
Thymosin Beta-4
TB4's primary mechanism involves sequestering G-actin monomers (via its LKKTET actin-binding domain) to regulate actin cytoskeleton dynamics — critical for cell migration, wound closure, and tissue remodeling. Clinical trials have evaluated TB4 for corneal wound healing (Phase 2), pressure ulcers, and cardiac repair after MI. The FACT trial investigated TB4 in patients with ischemic heart failure, showing trends toward improved cardiac function. Anti-inflammatory effects are mediated partly through NF-κB pathway downregulation.
This comparison aggregates public research and structured profile data for informational purposes only. It is not medical advice and does not recommend either compound for human use. Consult a qualified healthcare provider before considering any peptide.