# Thymosin Alpha-1 Dosage: The Doses, Routes, and Durations Studied

> Thymosin Alpha-1 dosage in the research context — the subcutaneous doses, twice-weekly and sepsis regimens, half-life, and routes studied in trials. Not a recommendation.

A research-context summary of the Thymosin Alpha-1 doses, routes, durations, and half-life reported in trials — described in third person, never as a personal protocol.

## Start here

This is a description of how **Thymosin Alpha-1** was *dosed in studies* — not a how-to, not a recommendation, and not a protocol to copy. Everything below reports what researchers gave to specific groups of patients, by which route, for how long.

The short version: in trials it's given as a subcutaneous (under-the-skin) injection. The long-running hepatitis regimen is small and twice weekly; sepsis and COVID-19 studies used more frequent dosing over a short stretch of days. The synthetic form (thymalfasin) is approved abroad, so much of this dosing comes from real clinical settings in other countries. After a shot, blood levels rise within an hour or two and return toward baseline within about a day. None of that tells *you* what to do — it tells you what was tested.

## Thymosin alpha 1 dosage: the studied ranges

A comprehensive four-decade review reports the standard single subcutaneous dose of **thymosin alpha 1** ranging from 0.8 to 6.4 mg, with multiple-dose regimens of 1.6 to 16 mg given over five to seven days [4]. The most familiar regimen is the chronic-hepatitis pattern: 1.6 mg subcutaneously twice weekly [4]. These are reported strictly as studied doses in clinical populations, not as guidance. The review also notes the synthetic peptide is approved in more than 35 countries and is usually well tolerated, with local injection-site irritation the most common adverse effect [4].

## Thymosin alpha 1 injection: routes and regimens

Essentially every clinical trial used the **thymosin alpha 1 injection** route of subcutaneous administration [4]. The sepsis trials clustered around 1.6 mg every 12 hours for five to seven days: ETASS used 1.6 mg every 12 hours for 5 days, then once daily for 2 days [2], while the phase-3 TESTS protocol used 1.6 mg every 12 hours for 7 days [3]. COVID-19 cohort studies generally used 1.6 mg subcutaneously daily [6]. Beyond clinical trials, the peptide has also been administered in vitro and ex vivo in mechanistic studies, and intraperitoneally in mouse models [5][8] — but the human route of record is subcutaneous injection.

## Half-life and pharmacokinetics

After a subcutaneous injection in human volunteers, Tα1 shows roughly a 2-hour elimination half-life, with peak blood levels around 1–2 hours and a return toward baseline within about 24 hours; its volume of distribution is consistent with distribution through extracellular fluid [4]. It's a highly acidic peptide (isoelectric point around 4.2), doesn't bind plasma proteins extensively, and is broken down by tissue and circulating aminopeptidases [4]. It's supplied lyophilized (freeze-dried), and — because the N-terminal acetyl cap is required for activity — identity and handling matter for whether the molecule works at all [1][4].

## Durations studied

Study durations track the indication. Sepsis protocols ran short — 5 to 7 days [2][3]. COVID-19 cohorts dosed daily over the acute illness [6]. The chronic-hepatitis regimen runs far longer at twice weekly, and cancer-adjuvant work has used weekly subcutaneous injection for up to 12 months in chemoradiotherapy-adjunct settings [4]. Across all of these, the literature describes a benign safety profile dominated by mild local reactions, with no documented organ toxicity at studied doses [4][10]. Once more: these are durations *studied*, reported here so the research record is legible — not a schedule to follow.

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A bright, plainly-cited read of the Thymosin Alpha-1 record — the immune-peptide signals lit up, the strongest trial's null result kept right in frame, and the look-alike molecules pulled apart; no clinic behind the masthead and nothing here dosed, prescribed, or sold.