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Bioalmanac

Thymosin alpha-1

Tα1 · Thymalfasin · Zadaxin (brand)

Approved for another indication

Status reviewed 12 Aug 2026

An immune-modulating peptide approved in more than thirty countries for hepatitis B, and studied in sepsis and as a vaccine adjuvant. Not approved in the United States.

Storage

Freeze-dried powder
Refrigerated at 2–8 °C, protected from light.
After mixing
Refrigerated at 2–8 °C. Do not freeze once mixed.
Long-term, frozen
Unopened powder is stable at −20 °C or colder.

Reconstitution — 10 mg vial, 1600 mcg dose

On a 1 mL U-100 syringe. Check every figure against your own vial before drawing.

Water addedConcentrationVolume to drawUnitsDoses per vial
1 mL10 mg/mL0.16 mL16 units6.3
2 mL5 mg/mL0.32 mL32 units6.3
3 mL3.333 mg/mL0.48 mL48 units6.3
5 mL2 mg/mL0.8 mL80 units6.3

Dose ranges reported in sources

Descriptions of what sources report, not recommendations.

GoalRangeFrequencySource
Approved regimen for hepatitis B1600 mcgTwice weekly for six monthsClinical trial
Commonly described for general use450–1600 mcgTwo or three times weeklyCommunity practice

When to stop

  • Any new joint pain, rash, or unexplained fever. These can be early signs of immune activation going the wrong way.
  • Any allergic response: rash, hives, facial swelling or difficulty breathing. Seek urgent care.
  • A flare of any existing autoimmune condition.
  • Signs of infection at an injection site.

Approved as thymalfasin in more than thirty countries, principally for chronic hepatitis B. Not approved in the United States, where it is sold as a research chemical with no manufacturing standard behind it.

Arithmetic on values you enter. Not medical advice. Not reviewed by a clinician. · bioalmanac.com/peptides/thymosin-alpha-1

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