Thymosin Alpha-1 vs TB-500
Verdict: The most-confused pair in the peptide world: both carry 'thymosin', and they do nothing alike. Thymosin Alpha-1 is an immune modulator — T-cell maturation, used clinically in dozens of countries for hepatitis and as an immune adjunct, with a genuine human evidence base. TB-500 is a fragment of Thymosin Beta-4 used for soft-tissue healing. Immune resilience question → Alpha-1. Injury recovery question → TB-500. The shared surname is an accident of discovery history, not chemistry.
Side by side
| Thymosin Alpha-1 | TB-500 | |
|---|---|---|
| Typical dose | 450 mcg–1.6 mg | 2 mg–5 mg |
| Frequency | 2x weekly | 2x weekly (loading), then 1x weekly |
| Administration | subcutaneous injection | subcutaneous injection |
| Common vials | 5 mg, 10 mg | 5 mg, 10 mg |
| Typical mix | 5 mg + 2 ml water | 5 mg + 2.5 ml water |
| Units for typical dose | 64 units (1.6 mg) | 125 units (2.5 mg) |
Two unrelated mechanisms
Thymosin Alpha-1 enhances T-cell differentiation and dendritic cell function via toll-like receptor signaling — an immune-system conductor. TB-500/TB4 regulates actin polymerization, letting cells migrate into damaged tissue — a wound-site logistics manager. Different receptors, different tissues, different outcomes.
Evidence: one of these is a real drug
Thymalfasin (Thymosin Alpha-1) is approved in 35+ countries, with RCTs in hepatitis B/C, sepsis and as vaccine adjunct — arguably the strongest human evidence of any peptide on this site. TB-500 as an injected fragment remains preclinical, borrowing plausibility from TB4's trial history in wound healing.
Dosing patterns
Thymosin Alpha-1: 1.6 mg subcutaneously twice weekly is the clinically established rhythm. TB-500: 2–5 mg weekly, often front-loaded during the first month of an injury protocol. Both are milligram-scale peptides requiring larger vials than the microgram GH-axis compounds.
Can you stack them?
No overlap, so they stack without redundancy — occasionally combined in recover-from-everything protocols (illness + injury). But most users need only the one matching their actual problem.
More comparisons
Educational comparison based on commonly published research protocols — not medical advice or an endorsement of any compound.