Where to buy Thymosin Alpha-1 (thymalfasin, Zadaxin) in the UK: the sellers with a verifiable COA
The newest verifiable Thymosin Alpha-1 certificate on any UK seller's website is on Peptology Labs (peptologylabs.uk), analysed 18 Sep 2026 (task #233906 on Janoshik's site); 3 verified sellers hold one covering Thymosin Alpha-1, listed newest first below.
A record of paperwork, not a recommendation: The Peptide Watch sells nothing, takes no money from sellers and links to none of them.
Who has the newest report · Why the date matters · What purity means · What Thymosin Alpha-1 is · Regulators · Every report
Who holds the newest Thymosin Alpha-1 report (3 verified UK sellers)
Newest report first. Every report was opened on Janoshik's own website and names the seller as the client. The date is the analysis date printed on the report. The verify link opens the laboratory, never the shop. Audit findings, not recommendations.
| Seller | Newest Thymosin Alpha-1 report | Age of that report | Purity on it | |
|---|---|---|---|---|
| Peptology Labs | 18 Sep 2026 | 25 days | 99.885% | verify |
| Biohackpeptides | 21 May 2026 | 4 months, 22 days | 99.904% | verify |
| Thoroughbredlabs | 12 May 2026 | 5 months, 1 day | 99.202% | verify |
Every Thymosin Alpha-1 purity report we have read (3), one row per report
The 3 verifiable Thymosin Alpha-1 certificates we have read, newest first
Each row was opened on Janoshik's own site by a real page load and transcribed. The client column is the name the laboratory printed; a certificate counts as a seller's own only when that name is the seller. The report date is the analysis date printed on the report where we have read it, otherwise the date the laboratory received the sample. The verify link opens the laboratory, never the shop. Audit findings, not recommendations.
| Seller | Task | Client on the report | Report date | Result | Batch | |
|---|---|---|---|---|---|---|
| Peptology Labs | #233906 | Peptology Labs | 18 Sep 2026 | Thymosin Alpha-1 · 5.36 mg · 99.885% | TA2865 | verify |
| Biohackpeptides | #162922 | BiohackPeptides.co.uk | 21 May 2026 | Thymosin Alpha-1 · 4.51 mg · 99.904% | BHP26ETA5 | verify |
| Thoroughbredlabs | #155575 | Thoroughbred Labs | [email protected] | 12 May 2026 | Thymosin Alpha-1 · 5.58 mg · 99.202% | TBLTA103 | verify |
Why the date on a certificate matters
What a purity figure means
The purity on a Janoshik report is the share of the main peak in an HPLC chromatogram. 99.5% means that 99.5% of what the detector saw was one substance and 0.5% was something else. It is not the amount in the vial: that is the separate quantity line, in milligrams. It does not by itself prove which substance the peak is: that is identity, confirmed by mass spectrometry. And it says nothing about sterility, endotoxins or heavy metals, which are separate tests.
A purity figure printed on a shop page with no report behind it is a claim, not a measurement. Between two reports, the difference that matters is rarely 99.2% against 99.8%; it is whether the report exists at all, names the seller as the client, covers this compound on its own, and is recent.
What Thymosin Alpha-1 is, and what it is sold as
Thymosin alpha-1 is a 28-amino-acid thymic peptide isolated in 1977 and sold as thymalfasin (Zadaxin) in 37 countries, chiefly China, for hepatitis B and as a vaccine adjuvant. It has never been approved by the FDA, the EMA or the MHRA, and the largest recent trial, in sepsis, found no effect on mortality.
| Development status | Licensed elsewhere, not in the UK, US or EU. Licensed in 37 countries, chiefly China, for hepatitis B and as a vaccine adjuvant. Never approved by the FDA, the EMA or the MHRA. |
|---|---|
| Originator | Allan Goldstein and colleagues, 1977 (isolated from thymosin fraction 5 of calf thymus). Rights: SciClone Pharmaceuticals (Zadaxin); generic thymalfasin is made by several Chinese manufacturers. |
| Registered clinical trials | 64 on ClinicalTrials.gov |
A licensed medicine in 37 countries, none of them the UK, the US or the EU. Thymosin alpha-1 was isolated from calf thymus by Allan Goldstein's group in 1977. SciClone's version, thymalfasin (Zadaxin), is approved in 37 countries according to the sponsor's own trial record, chiefly China, for hepatitis B and to boost vaccine response; it has never been approved by the FDA or the EMA and the electronic medicines compendium lists no UK product. PubMed indexes 887 papers, 91 clinical-trial reports and 5 phase 3 reports; ClinicalTrials.gov lists 64 registered trials, most run by Chinese hospitals.
The largest recent trial was negative. TESTS, published in the BMJ in 2025, randomised 1,106 adults with sepsis in China to thymosin alpha-1 or placebo: 28-day mortality was 23.4% against 24.1%, no clear effect. A 2026 Cochrane review of its use in chronic hepatitis B rated the evidence for a mortality benefit as very low certainty, from three small trials. Sellers describe it as an immune booster; the literature is a drug with a narrow, contested indication.
What a certificate can tell you. The two purity reports we read recovered 4.51 mg (99.904%) and 5.58 mg (99.202%) on 5 mg labels. Neither says anything about sterility or endotoxin, which for a 28-amino-acid injectable are the questions that matter.
The published record in numbers, and the sources
| Papers on PubMed | 887 |
|---|---|
| Indexed as rat or mouse studies | 269 |
| Indexed as clinical trials | 91 |
| Published since 2020 | 162 |
Counts are from PubMed on 15 September 2026 using the queries recorded in our evidence file. A description of the published record, not medical advice and not an argument for or against use.
- Thymosin alpha1: isolation and sequence analysis of an immunologically active thymic polypeptide. (Proc Natl Acad Sci U S A, 1977, PMID 265536)
- The efficacy and safety of thymosin α1 for sepsis (TESTS): multicentre, double blinded, randomised, placebo controlled, phase 3 trial. (BMJ, 2025, PMID 39814420)
- Thymosin-ɑ1 for people with chronic hepatitis B. (Cochrane Database Syst Rev, 2026, PMID 42713852)
- Immune enhancement in patients with predicted severe acute necrotising pancreatitis: a multicentre double-blind randomised controlled trial. (Intensive Care Med, 2022, PMID 35713670)
- The efficacy and safety of thymosin alpha-1 in Japanese patients with chronic hepatitis B; results from a randomized clinical trial. (J Viral Hepat, 2005, PMID 15850471)
- Thymosin α-1 in Cancer Therapy: Immunomodulatory Mechanisms, Clinical Applications, and Translational Perspectives. (Eur J Pharmacol, 2026, PMID 42641753)
- ClinicalTrials.gov NCT04487444, sponsor's description of Zadaxin approvals
- electronic medicines compendium, UK product search for thymalfasin
What regulators say about Thymosin Alpha-1
In the UK. No UK marketing authorisation; the emc lists no thymalfasin product. Sold here as a research chemical.
We hold no statement from the FDA, MHRA or EMA specifically about Thymosin Alpha-1 on file. Its development and licence sources are listed under the record above.
What the 3 Thymosin Alpha-1 certificates show
We have read 3 Janoshik reports covering Thymosin Alpha-1, published by 3 UK sellers. Each was opened on Janoshik's own website. All 3 name the seller itself as the client. All 3 are dated within the last six months. The newest is dated 18 Sep 2026 and the oldest 12 May 2026.
All 3 reports give a purity figure for Thymosin Alpha-1. The figures run from 99.202% to 99.904%, and all 3 are at 99% or above. A purity figure describes the sample the laboratory received, not every vial from that batch.
Read directly from the newest reports: Peptology Labs: task #233906, analysed 18 Sep 2026, 5.36 mg recovered at 99.885%, client Peptology Labs; Biohackpeptides: task #162922, sample received 21 May 2026, 4.51 mg recovered at 99.904%, client BiohackPeptides.co.uk; Thoroughbredlabs: task #155575, sample received 12 May 2026, 5.58 mg recovered at 99.202%, client Thoroughbred Labs.
A certificate is a batch document. The lines that matter are the compound (it must say Thymosin Alpha-1, not only a batch code), the client (the shop, not its supplier) and the analysis date. A new batch is untested until a new report appears.
Thymosin Alpha-1 in the UK at a glance
| Active UK sellers listing Thymosin Alpha-1 | 6 |
|---|---|
| Of which publish a verifiable own-name certificate | 3 |
| Of which name no laboratory at all | 0 |
Counted from the vendor ledger at build time. The A-Z directory lists every seller and what each publishes instead.
Questions people ask
Which UK sellers publish a verifiable Janoshik certificate naming Thymosin Alpha-1?
As of 13 October 2026, 3: Peptology Labs, Biohackpeptides, Thoroughbredlabs. Each has a report on Janoshik's own website that names the seller as the client and lists Thymosin Alpha-1. That is a statement about paperwork, not a recommendation; The Peptide Watch does not recommend anywhere to buy Thymosin Alpha-1.
How recent is the newest Thymosin Alpha-1 certificate from a UK seller?
The newest we have read is Janoshik task #233906, analysed 18 Sep 2026. It is published by Peptology Labs and names it as the client. A certificate covers one batch, so an old one says little about stock on sale today.
How do I check that a certificate for Thymosin Alpha-1 is genuine?
Four things: an independent laboratory is named; the client field names the seller you are buying from, not a supplier; the compound line says Thymosin Alpha-1; and the report's task number and key open the same report on the laboratory's own website (verify.janoshik.com). A branded PDF with no laboratory name and no verification code fails on the first check, however professional it looks. The free COA Checker on this site runs the checks for you.
Is Thymosin Alpha-1 a licensed medicine in the UK?
No UK marketing authorisation; the emc lists no thymalfasin product. Sold here as a research chemical. Licensed in 37 countries, chiefly China, for hepatitis B and as a vaccine adjuvant. Never approved by the FDA, the EMA or the MHRA. The Peptide Watch does not give legal or medical advice.
Why does The Peptide Watch not say where to buy Thymosin Alpha-1?
Because the site records paperwork, not recommendations. A verifiable certificate proves that a sample of one batch was tested. It does not prove the vial you receive matches it, and it says nothing about whether anyone should use Thymosin Alpha-1. Listing which sellers publish a certificate you can check, and which publish nothing, is as far as the evidence goes.
The Peptide Watch's position on Thymosin Alpha-1
No UK marketing authorisation; the emc lists no thymalfasin product. Sold here as a research chemical. The Peptide Watch reads the certificates UK sellers publish and does not recommend anywhere to buy Thymosin Alpha-1. Sellers on this page are listed by the date of their newest Thymosin Alpha-1 certificate and by nothing else. If you can verify a seller's testing, you can at least judge its evidence; if you cannot, you are taking the seller's word for what is in the vial. See how UK testing compares across every seller in the market statistics.
An honest note: a verifiable certificate proves a sample of a batch was tested, not that the specific vial you receive matches it, see what this can and can't tell you. The Peptide Watch sells no Thymosin Alpha-1 and links to no shop; this is research-use-only information, not medical or dosing advice.
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