Thymosin alpha-1 vs Thymosin beta-4 half-life
Thymosin alpha-1 has an elimination half-life of about 2 h; Thymosin beta-4 has about 1.5 h. Despite the shared name, these are unrelated proteins first isolated from thymus tissue. Thymosin alpha-1 (thymalfasin) is an immune modulator approved in some countries; thymosin beta-4 is an actin-binding protein studied for tissue repair.
Side by side
| Thymosin alpha-1 | Thymosin beta-4 | |
|---|---|---|
| Half-life | 2 h (range 1.6–2 h) | 1.5 h (range 30 min–2.1 h) |
| Route | SC | IV / SC |
| Category | Longevity & mitochondrial | Healing & repair |
| Evidence | Clinical | Limited |
| Remaining after 24 hours | 0.02% | <0.01% |
| Remaining after 7 days | <0.01% | <0.01% |
| ~97% cleared (5 half-lives) | 10 h | 7.5 h |
| Steady state (4-5 half-lives) | 8 h to 10 h | 6 h to 7.5 h |
Single-dose decay
Share of one dose remaining over time, assuming first-order elimination. Dashed lines mark each half-life.
Thymosin alpha-1 (t½ 2 h) Thymosin beta-4 (t½ 1.5 h)
Thymosin alpha-1: Approved outside the US: about 2 hours. Thymosin beta-4: Phase 1 (IV, recombinant): terminal half-life 0.5–2.1 hours.
FAQ
Which lasts longer, Thymosin alpha-1 or Thymosin beta-4?
Thymosin alpha-1 lasts longer. Its half-life is about 2 h, versus 1.5 h for Thymosin beta-4, roughly 1.3 times longer.
How long do Thymosin alpha-1 and Thymosin beta-4 stay in your system?
With first-order elimination, about 97% of a single dose is cleared after five half-lives: roughly 10 h for Thymosin alpha-1 and 7.5 h for Thymosin beta-4. Individual clearance varies.
How long until Thymosin alpha-1 and Thymosin beta-4 reach steady state?
With consistent repeated dosing, levels approach steady state after 4 to 5 half-lives: about 8 h to 10 h for Thymosin alpha-1, and 6 h to 7.5 h for Thymosin beta-4.
How reliable are these half-lives?
Thymosin alpha-1: Clinical evidence. Thymosin beta-4: Limited evidence. Anecdotal values are community estimates and may be far off.