Thymosin Alpha 1: Immunomodulatory Peptide Research Guide (2026)
Last updated
Introduction (research-only scope)
Thymosin alpha 1 is a 28-amino-acid peptide originally isolated from thymus tissue, where it participates in the maturation of immune cells. It is unusual in this catalog because it exists both as a research reagent and, under the name thymalfasin, as an approved medicine in a number of countries. This guide covers the biology, the evidence and that regulatory distinction.
Research use only. The material described here is a laboratory reagent for in-vitro research by qualified professionals. It is not a medicine, supplement, cosmetic ingredient or veterinary product, is not for human or animal use, and nothing on this page is medical advice or a claim of effect in any person.
What is Thymosin Alpha 1?
Thymosin alpha 1 (molecular mass 3108.32, CAS 62304-98-7) is the N-terminally acetylated fragment of prothymosin alpha. It was characterised by Allan Goldstein and colleagues, the same group behind the beta-thymosin work that produced TB-500, though the two families are biologically distinct: alpha 1 is immunological, beta 4 is cytoskeletal. Peptra Labs supplies it as a lyophilised research reagent, 10 mg per vial.
How the reported mechanism works
T-cell maturation and innate signalling
The reported mechanism centres on the maturation and function of T cells and on signalling through pattern-recognition receptors on dendritic cells, which is the basis for its study as an immune modulator rather than an immune stimulant in the crude sense.
Proteostasis
A 2018 paper in Expert Opinion on Biological Therapy described effects on cellular proteostasis, adding a mechanism outside the classical immunological account and illustrating that the pharmacology is still being mapped.
What the published evidence covers
Because thymalfasin is licensed in some countries, the clinical literature is larger and more independent than for most compounds here: long-term follow-up in metastatic melanoma published in 2018, and work in hepatitis B-related liver failure as recently as 2026. Those studies used the pharmaceutical product in patients under medical supervision and describe that product, not research-grade material. For laboratory work the compound is a standard tool in immune-cell assays.
How to verify a Thymosin Alpha 1 research peptide is real and pure
Two tests answer two different questions: mass spectrometry confirms identity (expected molecular mass 3108.32), HPLC quantifies purity. Our specification is at least 98%. Check the batch number printed on your vial against the lab reports archive: where a batch has been tested, its report is published there and links to the testing laboratory’s own verification page. If your batch is not listed yet, ask us for its documentation before use; a “typical” certificate is not evidence for a specific vial. See how to read a certificate of analysis.
Storage and reconstitution
Store the lyophilised material sealed, dry and protected from light at 2 to 8 °C for routine laboratory use, colder for long-term archiving. After reconstitution with bacteriostatic water, keep refrigerated and use within the window your protocol defines; repeated freeze-thaw cycles degrade peptides. General handling for all our reagents is in the peptide storage protocol.
Regulatory status
Thymosin alpha 1 is approved as a medicine under the name thymalfasin in a number of countries and holds orphan designations, but it is not FDA-approved in the United States; we make no statement about its current status in any specific European country, which can be checked in the relevant national or EMA register. The reagent supplied here is not that medicinal product. It is not named individually on the WADA Prohibited List, and because approvals exist in some jurisdictions the general S0 clause may not apply to it in the same way as to unapproved compounds; athletes should treat the live list as binding. Research-grade material supplied here is not a medicine and is for in-vitro laboratory use only. The wider framework, including anti-doping status, is described in the peptide risk profile.
Why labs choose our Thymosin Alpha 1
Batch-numbered vials, published reports where a batch has been tested, shipping from an EU warehouse with tracking (no customs inside the EU) and prices shown with VAT included. Product page: Thymosin Alpha 1 10 mg. Country-by-country sourcing questions are covered in the buyer guide Buy Thymosin Alpha 1 in Europe.
References
- Pica F et al. Long-term follow up of metastatic melanoma patients treated with Thymosin alpha-1. Expert Opin Biol Ther. 2018. PubMed 30063847
- Matteucci C et al. Cellular proteostasis: a new twist in the action of thymosin alpha 1. Expert Opin Biol Ther. 2018. PubMed 30063867
- Thymosin alpha 1 improves the outcomes of patients with hepatitis B virus-related acute-on-chronic liver failure. Immunopharmacol Immunotoxicol. 2026. PubMed 41887933