What it is
Thymosin alpha-1 is an immune-modulating peptide studied for enhancing T-cell function and natural killer (NK) cell activity, two components of the immune system. It has been studied in chronic viral infections such as hepatitis B and C, and it is used in integrative medicine settings for general immune support.
In the PeptidesAI encyclopedia it is categorized under immune and longevity, alongside compounds such as NAD+ and MOTS-c.
How it's thought to work
Thymosin alpha-1 is studied for enhancing the maturation and differentiation of T-cells, increasing NK cell activity, modulating cytokine production (the signaling proteins immune cells use to communicate), and supporting dendritic cell function, all of which contribute to immune surveillance, the body's ongoing monitoring for infection or abnormal cells. Supporting several of these processes together is presented as the reason thymosin alpha-1 is described as a broad immune modulator rather than a compound with one narrow target.
What the research says
Thymosin alpha-1 is reported to be approved in some countries outside the United States. It is not approved by the FDA: a 2024 FDA review prepared for its Pharmacy Compounding Advisory Committee concluded there was insufficient evidence of effectiveness for the uses it evaluated. Human trials exist, including a randomized trial in chronic hepatitis C that combined it with interferon (Sherman et al., 1998), with mixed results.
Reported side effects
Rare injection site reactions have been reported.
Reconstitution
Thymosin alpha-1 is supplied as a lyophilized (freeze-dried) powder and is typically reconstituted with bacteriostatic (BAC) water before use. It commonly comes in 1.6 mg and 3.2 mg vials. The amount of peptide in the vial is fixed; the water added only changes how concentrated the solution is.
Worked example. A 3.2 mg vial is 3,200 mcg. Reconstituted with 1 mL of BAC water, that works out to 3,200 mcg ÷ 1 mL = 3,200 mcg/mL. On a U-100 insulin syringe, where each unit is 0.01 mL, each unit holds 3,200 × 0.01 = 32 mcg. A 1.6 mg vial with 1 mL comes out at 1,600 mcg/mL instead, or 16 mcg per unit. Use the peptide reconstitution calculator to work out the concentration and units for any vial size and water volume.
Important notes
Thymosin alpha-1 is not FDA-approved. Its approval status in other countries could not be independently verified by the FDA in its 2024 review.
Sources
- Combination therapy with thymosin alpha1 and interferon for the treatment of chronic hepatitis C infection: a randomized, placebo-controlled double-blind trial. Sherman KE et al. Hepatology, 1998. Human trial
- Thymosin alpha1: the regulator of regulators?. Pierluigi B et al. Annals of the New York Academy of Sciences, 2010. Review
- Thymosin Alpha-1 (Ta1) Related Bulk Drug Substances (Pharmacy Compounding Advisory Committee briefing). U.S. Food and Drug Administration, 2024. Regulatory document
Frequently asked questions
These questions cover the same ground as the sections above, in a shorter format.
What is Thymosin alpha-1?
An immune-modulating peptide studied for enhancing T-cell and NK cell activity. It is reported to be approved in some countries outside the US, but not by the FDA.
How is Thymosin alpha-1 thought to work?
It is studied for enhancing T-cell maturation, increasing NK cell activity, modulating cytokine production, and supporting dendritic cell function.
What does the research on Thymosin alpha-1 say?
Human trials exist, including in chronic hepatitis C, but a 2024 FDA review found insufficient evidence of effectiveness for the uses it evaluated. It is not FDA-approved.
What are the reported side effects of Thymosin alpha-1?
Rare injection site reactions have been reported.
How much is one unit from a 3.2 mg Thymosin alpha-1 vial?
With 1 mL of BAC water, a 3.2 mg vial is 3,200 mcg/mL, so one unit on a U-100 syringe (0.01 mL) holds 32 mcg.
The full entry, plus the calculator
The PeptidesAI app has the complete encyclopedia entry for Thymosin alpha-1 — one of 70 compounds covered — plus the reconstitution calculator, a dose log and reminders. Free to download on iPhone.
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