Thymosin Alpha-1
Immune modulator. Thymosin Alpha-1 is Not FDA approved · approved abroad; research-chemical versions are not the approved drug.
Also called:TA1thymalfasinZadaxin
Medically reviewed by Juan Pablo Frías, MD · · DisclosureUpdated Strongest evidence: Human RCT evidence, 4 of 4
Key facts
How we verify- Class
- Immune modulator
- Also called
- TA1, thymalfasin
- Half-life
- elimination half-life less than 3 hours; Tmax 1-2 hours
- subcutaneous, in people · International journal of clinical pharmacology and therapeutics 1999, PMID 10027483
- FDA status
- Not FDA approved · approved abroad
- No approved product found
- WADA
- Unclear
- Not named on the 2026 list
Everything on Thymosin Alpha-1
Thymosin Alpha-1 guides
01DosageDoses used in published studies, with the source for each.02Side effectsWhat labels and studies report, and what is unknown.03ResultsStudy outcomes and when they were measured.04PricePrice per mg and per week from dated listings. No vendor links.05For immune systemWhat research says about Thymosin Alpha-1 for immune system.
Evidence at a glance
Human and animal counts are PubMed records from our evidence ledger (search counts, not studies we reviewed). The grade is the strongest design among the studies we summarised for that goal: a human randomized trial outweighs any number of animal studies.
| Condition | Human studies | Animal studies | Studies we summarised | Evidence grade |
|---|---|---|---|---|
| Immune system | 222 | 101 | 10 | Human RCT evidence, 4 of 4BMJ 2025, PMID 39814420 |
Grades follow our evidence scale. Summarised studies come from our evidence file, each quote checked against the abstract or label.
Common questions
Is Thymosin Alpha-1 FDA approved?
Thymosin Alpha-1 is Not FDA approved · approved abroad. Products sold as research chemicals are not the approved drug and are not checked by the FDA.
Sources
- 1US search volume and year-over-year trend, Google Keyword Planner export (Jun–Aug 2026 vs 2025)Peptigraph research · 2026peptigraph.com/methodology/Accessed 1 Oct 2026
- 2World Anti-Doping Code International Standard Prohibited List 2026World Anti-Doping Agency · 2026wada-ama.orgAccessed 2 Oct 2026
- 3United States: No FDA-approved product found: Drugs@FDA (openFDA) search for active ingredient "Thymosin Alpha-1" returned no matches on 2 Oct 2026.U.S. Food and Drug Administration · 2026api.fda.govAccessed 2 Oct 2026
- 4US compounding: Thymosin alpha-1 appears in FDA's table of bulk drug substances previously in category 2 and withdrawn by the nominators.U.S. Food and Drug Administration · 2026fda.govAccessed 2 Oct 2026
- 5The efficacy and safety of thymosin α1 for sepsis (TESTS): multicentre, double blinded, randomised, placebo controlled, phase 3 trial.BMJ (Clinical research ed.) · 2025PMID 39814420Accessed 2 Oct 2026
- 6Pharmacokinetics of thymosin alpha1 after subcutaneous injection of three different formulations in healthy volunteers.International journal of clinical pharmacology and therapeutics · 1999PMID 10027483Accessed 2 Oct 2026
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