Thymosin alpha-1 FAQ: common questions answered
An immune-signaling peptide with overseas approvals and mixed trial results.
Also called: Thymalfasin, TA1, Tα1, Thymosin α1, Zadaxin.
Immune peptides · Synthetic 28-amino-acid thymic immune modulator · Evidence: Approved drug.
- Is Thymosin alpha-1 FDA-approved? No FDA-approved TA1 product. FDA issued a December 7, 2020 warning over TA1 COVID claims. A committee vote or overseas approval is not US approval.
- How do people take it? Under the skin, twice weekly. 26 weeks. Source: studied in a trial.
- What's the difference between Thymosin alpha-1 and BPC-157? Thymosin alpha-1: an immune-signaling peptide with overseas approvals and mixed trial results. BPC-157: an experimental repair peptide with mostly animal evidence and a few small human reports. Why people pair them: reported in recovery or long-COVID stacks; no human trial located for the combination.
- Can I take it with BPC-157? Reported in recovery or long-COVID stacks; no human trial located for the combination. Combined safety is unknown, and several simultaneous drugs obscure the cause of benefit or harm. Source: reported by users. Ask a doctor before combining anything.
- Is it banned in sport? It is unclear (WADA 2026). TA1 is not named. S0 concerns substances with no approval anywhere; TA1 has overseas approvals. Beta-4/TB-500 is S2.3. Obtain an anti-doping ruling.
- How long does a mixed vial last? Use Zadaxin immediately after mixing; no supported multiweek refrigerated beyond-use time was located.
Related to Thymosin alpha-1
- VIP: A blood-vessel and immune signal studied in lung disease; nasal CIRS benefits remain unproven.
- BPC-157: An experimental repair peptide with mostly animal evidence and a few small human reports.
- TB-500: A short piece of thymosin beta-4 with no proven repair benefit in humans.
- GHK-Cu: A copper-binding skin peptide with small topical studies and untested systemic injections.
- MOTS-c: A peptide the body makes; injection benefits and safety remain unproven.
- Epitalon: A peptide with telomerase effects in cells, but no proof that people live longer.
Sources
- 21 CFR 216.23 — Bulk drug substances that can be used to compound drug products in accordance with section 503A of the Federal Food, Drug, and Cosmetic Act., Office of the Federal Register · eCFR · 2026
- 503B Bulk Drug Substances List, FDA · FDA · 2026
- Bulk Drug Substances Nominated for Use in Compounding Under Section 503A of the Federal Food, Drug, and Cosmetic Act, FDA · FDA · 2026
- Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks, FDA · FDA · 2026
- MHRA Products | Home, MHRA · MHRA · 2026
- TGA strengthens compliance focus on unapproved peptide products as part of evolving risk response, Therapeutic Goods Administration · TGA · 2026
- The 2026 Prohibited List, World Anti-Doping Agency · WADA · 2026
- The Prohibited List, World Anti-Doping Agency · World Anti-Doping Agency · 2026
- Think twice before injecting peptides bought online: unauthorized products can seriously harm you, Health Canada · Health Canada · 2026
- Thymosin Alpha 1 [Zadaxin], Singapore National Drug Formulary · 2026
- Bulk Drug Substances Nominated for Use in Compounding Under Section 503B of the Federal Food, Drug, and Cosmetic Act, FDA · FDA · 2025
- December 4, 2024 Pharmacy Compounding Advisory Committee (PCAC) Meeting, FDA · 2024
- December 4, 2024 Pharmacy Compounding Advisory Committee Meeting, FDA · 2024
- Fraudulent Coronavirus Disease 2019 (COVID-19) Products, FDA · 2020
- Public summary of positive opinion for orphan designation of thymalfasin for the treatment of hepatocellular carcinoma, European Medicines Agency
Sources checked: 2026-10-18.
Information only, not medical advice. Peptifacts does not sell anything and does not link to sellers.