Thymalfasin · Tα1

Thymosin Alpha-1 in Canada

Also known as Tα1 · Thymalfasin · Zadaxin (approved product abroad) · Thymosin α1 · Ta1

Thymosin alpha-1 (Tα1, thymalfasin) is a 28-amino-acid acetylated peptide first isolated from calf thymus in 1977 and now produced synthetically. It acts on the innate immune system — Toll-like receptors on dendritic cells — and downstream on T-cell maturation and natural-killer activity. Unusually for a peptide sold for research, it is an approved medicine in more than thirty countries under the brand name Zadaxin, for chronic hepatitis B and as an immune adjuvant, and it has been through randomised trials in sepsis, melanoma and severe COVID-19. It holds no authorisation in Canada or the United States. Canada Peptides carries research-grade thymosin alpha-1 as a lyophilised vial, priced and shipped in CAD for laboratory and research use only.

Quick facts

Class: Thymic immunomodulatory peptide (thymalfasin); N-terminal fragment of prothymosin α
Structure: 28 amino acids, N-acetylated · Ac-Ser-Asp-Ala-Ala-Val-Asp-Thr-Ser-Ser-Glu-Ile-Thr-Thr-Lys-Asp-Leu-Lys-Glu-Lys-Lys-Glu-Val-Val-Glu-Glu-Ala-Glu-Asn · ~3,108 Da
Half-life: About 2 hours in plasma after subcutaneous injection; immune effects persist for days
Route in research: Subcutaneous in clinical trials and the approved product abroad
Cadence in research: 1.6 mg twice weekly in the licensed hepatitis B regimen; twice weekly to twice daily in trials
Storage: Lyophilised: refrigerated, dark. Reconstituted: refrigerated, used within weeks

Thymosin Alpha-1 FAQ

Is Thymosin Alpha-1 for sale in Canada?

Yes. Research-grade thymosin alpha-1 is available in Canada from Canada Peptides as a lyophilised vial, priced and shipped in CAD. It is supplied strictly for laboratory and research use, not for human consumption, and it is not the approved product Zadaxin.

What is thymosin alpha-1?

A 28-amino-acid acetylated peptide first isolated from calf thymus in 1977, now made synthetically. It acts on Toll-like receptors on dendritic cells and downstream on T-cell and natural-killer function. Under the name thymalfasin (Zadaxin) it is an approved medicine in more than thirty countries, though not Canada or the United States.

What does the research on thymosin alpha-1 actually show?

Randomised trials in chronic hepatitis B reported higher sustained response rates with 1.6 mg twice weekly; a 361-patient sepsis trial reported a non-significant mortality reduction; a 488-patient melanoma trial found improved response rate but not survival; COVID-19 cohorts reported lower mortality but were not randomised. Tolerability was consistently good.

What is the half-life of thymosin alpha-1?

About two hours in plasma after subcutaneous injection, with peak concentration at one to two hours. The immune effects unfold over days to weeks because the endpoint is immune-cell differentiation, which is why clinical regimens run for weeks to months.

How was thymosin alpha-1 dosed in studies?

The unit dose is almost always 1.6 mg subcutaneously: twice weekly for six months in hepatitis B (the approved regimen abroad), twice daily for five days then daily for two in sepsis, and once or twice daily for about a week in COVID-19 cohorts. Those are facts about clinical trials and an approved product, not a recommendation; the material sold here is for research use only.

What side effects does thymosin alpha-1 research report?

Mainly injection-site discomfort and redness, with systemic events no more frequent than placebo in randomised trials and no dose-limiting toxicity identified. Theoretical concerns are aggravation of autoimmune disease and transplant rejection, and the labelling abroad advises caution in immunosuppressed people.

Is thymosin alpha-1 legal in Canada?

Thymosin alpha-1 is not a controlled substance in Canada, but it has no Health Canada approval for human use and no DIN. It may be sold for laboratory research, which is how it is sold here. It is not named on the WADA Prohibited List.

Is thymosin alpha-1 the same as TB-500?

No. Thymosin alpha-1 is a 28-residue immune-modulating peptide from prothymosin α. TB-500 is a fragment of thymosin β4, a 43-residue actin-binding protein from a different gene, studied for cell migration and tissue repair. They share only the historical name given to thymus extracts.

Thymosin Alpha-1 in Canada

Quick facts

Thymosin Alpha-1 — for sale in Canada

What is Thymosin Alpha-1?

Evidence at a glance

Pharmacology

Identity and chemistry

Storage and stability

Research indications

Research protocols

Interactions and stacking in research

Reconstitution and handling

Side effects and safety signals

Regulatory status in Canada

Further reading

Thymosin Alpha-1 FAQ

Research references