# Thymosin Alpha-1 Dosage in Research: Doses, Routes & Half-Life

> Thymosin Alpha-1 dosage as studied in research: the 0.8-6.4 mg single-dose range, the 1.6 mg twice-weekly regimen, subcutaneous route, and ~2-hour half-life. Research context only, no recommendations.

What was administered, to which populations, by which route — reported as research data, never as a recommendation.

## Read this first

This page describes the doses of Thymosin Alpha-1 used *in published studies*. It is not a protocol, not a recommendation, and not medical advice — there is no "how much should I take" answer here, because the molecule is not approved for sale in the United States and no dose is being prescribed. Where doses appear, they are written the way a researcher would log them: an amount, a population, and a route of injection, drawn straight from the trials. The numbers cluster in a tight band. Across four decades, single subcutaneous doses studied have ranged from roughly 0.8 to 6.4 mg, and the most familiar repeated regimen is 1.6 mg twice weekly. The half-life is short — about two hours in the blood. Everything below is third-person and study-attributed.

## Thymosin alpha 1 dosage: the studied ranges

A comprehensive review of four decades of clinical literature reports that the standard single subcutaneous dose of Thymosin Alpha-1 has ranged from 0.8 to 6.4 mg, with multiple-dose regimens of 1.6–16 mg given over five to seven days [4]. The most recognizable repeated regimen — the one tied to chronic-hepatitis settings abroad — is 1.6 mg subcutaneously twice weekly.

Trial protocols sit inside that band. The ETASS sepsis trial studied 1.6 mg subcutaneously every 12 hours for 5 days, then once daily for 2 days [2]. The phase-3 TESTS trial studied 1.6 mg every 12 hours for 7 days [3]. The COVID-19 cohorts used 1.6 mg daily [6]. The elderly influenza-vaccine trial studied 900 μg twice weekly for four weeks alongside vaccination [8]. These are recorded here only to show the research context — not as instructions for any person.

## Thymosin alpha 1 injection: route and pharmacokinetics

Across essentially every trial, the route was the same. Thymosin alpha 1 injection in the research record is subcutaneous — a shot into the fat layer under the skin — with in vitro and murine work covering the mechanistic studies. There is no oral form in the clinical literature; as a peptide it would be broken down in the gut.

The pharmacokinetics are quick. After subcutaneous injection in human volunteers, Thymosin Alpha-1 shows roughly a two-hour elimination half-life, with peak blood levels around one to two hours and a return toward baseline within about 24 hours; its volume of distribution is consistent with the extracellular fluid. It is a highly acidic peptide that does not bind plasma proteins extensively and is degraded by tissue and circulating aminopeptidases, which is why it is supplied freeze-dried [4]. The short half-life is part of why repeated dosing — rather than a single shot — is the pattern in the trials.

## Why no human dosing guidance appears here

Two reasons, both already on the table. First, Thymosin Alpha-1 is not FDA-approved in the United States [4]; there is no US label to quote and no approved indication to anchor a dose to. Second, the marketed dosing and outcomes that exist come from approved-abroad clinical settings under medical supervision — extrapolating them to unregulated or self-directed use is not supported by the evidence and falls outside any approved indication [4].

This site documents the literature. It does not tell anyone what to do with it. For the reported real-world experience — including how people describe tolerability — see the [Thymosin Alpha-1 effects](/effects) page, which keeps anecdote clearly labeled as anecdote.

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A naturalist's dive-log through four decades of the Thymosin Alpha-1 literature — each observation lit one at a time and cited to source, the null results left in plain view, with no clinic in the dark behind it and nothing here dispensed or sold.