Thymosin Alpha-1 Dosage, half-life & reference guide

Week by week.

What to expect in the first 8 weeks

1. Day 1–7Clinical

   Your immune system is getting instructions

   Commonly reported: nothing to feel in the first week. Thymosin alpha-1 helps T-cells mature and sharpens immune signaling, quiet work that users notice later, if at all, as fewer or milder colds.

   The science

   TA1 enhances T-cell maturation by promoting differentiation of T-cell precursors in the thymus. It upregulates MHC class I expression, improving antigen presentation and immune surveillance. Approved as Zadaxin for hepatitis B/C in over 35 countries.

   Sources

   • Garaci et al. (2012)
   • Tuthill et al. (2010)

   Updated Apr 2026

2. Day 7–14Clinical

   The immune side is ramping up

   Thymosin alpha-1 raises natural killer cell activity, your front-line immune defense. Many run it through cold and flu season or around travel, and judge it by how often they get sick over the months ahead rather than by any feeling this week.

   The science

   TA1 increases NK cell cytotoxicity and enhances dendritic cell function in lab studies (Garaci 2012). In hepatitis and cancer patients, T-cell responses were measured over months; no trial pins down a two-week timeline.

   Sources

   • Garaci et al. (2012)

   Updated Sep 2026

3. Day 14–28Clinical

   Where a common cycle ends

   Two to four weeks is where many cycles end. Commonly reported: the effect is subtle, and users judge it over a season by fewer or shorter colds. If you started it for a specific reason, note how that has gone since day 1.

   The science

   In hepatitis B, adding TA1 to interferon improved viral suppression and HBeAg seroconversion over interferon alone in a meta-analysis of 7 small trials (Mao 2011); a 2026 Cochrane review of 10 hepatitis B trials rated the overall evidence very low certainty (Naing 2026). The trials ran far longer than a community cycle: in one, 1.6 mg twice a week for 26 weeks cleared viral DNA and HBeAg in 40.6% by 18 months, against 9.4% untreated (Chien 1998). No study gives a 2–4 week steady state for its immune effects.

   Sources

   • Mao & Shi (2011)
   • Naing et al. (2026)
   • Chien et al. (1998)

   Updated Oct 2026

4. Any dayClinical

   What Thymosin Alpha-1 is built on

   One of the few peptides that is an approved prescription drug: Zadaxin (thymalfasin) is approved in about 35 countries, mainly for hepatitis B, and has decades of clinical use with a good safety record. It isn't approved in the US, and how much it helps is less settled than its safety.

   The science

   Originally isolated from thymic tissue by Allan Goldstein in the 1970s. Clinical trials span hepatitis B/C, HIV, cancer immunotherapy and vaccine response. A 2026 Cochrane review of 10 hepatitis B trials found very low certainty evidence of benefit, with serious adverse events not increased (Naing 2026). In the 1,106-patient TESTS sepsis trial, 28-day mortality was 23.4% on thymosin alpha-1 and 24.1% on placebo (Wu 2025). Mechanism: T-cell maturation, NK cell activation, dendritic cell stimulation, MHC-I upregulation.

   Sources

   • Garaci et al. (2012)
   • Naing et al. (2026)
   • Wu et al. (2025)

   Updated Sep 2026

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Mixing and a typical run.

Safety.

Goes with.

• LL-37
• KPV

Questions people ask.

Research.

Reference.

Cadence

2× weekly

2x/week

Half-life

~2 hours

~2 hours (Zadaxin label, after a SubQ dose)

Research basis

●●● Established

Clinical trials or FDA-approved use exists