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immune-modulating peptide

Thymosin Alpha-1 half-life & how long it lasts

By Melvin Morina · Updated 2026-07-27 · Zadaxin (approved in some countries)

Thymosin Alpha-1 has a half-life of about 2 hours, reaches peak concentration around 1 hours after a dose, and is practically cleared from the body about 10 hours after the last dose. Approved in a number of countries outside the US. About a 2 hour half-life in published work.

The numbers

Half-life2 hours
Time to peak1 hours
Routeinjection
Typical cadenceprotocols vary
Practically cleared10 hours after the last dose (five half-lives, ~97% eliminated)
Steady stateafter roughly 10 hours of continuous protocols vary dosing
Evidencelimited human data — directional only

What that means day to day

Sources

Track it instead of estimating it

Bo models this curve from your own logged doses, so you can see what is still in your system right now instead of doing the arithmetic. It also handles reconstitution math, dose reminders and injection-site rotation.

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Educational information only. Bo is a tracking app, not a medical device, and nothing here is medical advice, a dosing recommendation, or a substitute for your prescriber. Half-lives are population averages from the sources cited on each row; individual clearance varies with body weight, kidney and liver function, and other medication.