Encyclopedia entry · Longevity
Thymosin alpha-1
Thymosin alpha-1 (Talpha1, Zadaxin)
Thymosin alpha-1 is a 28-amino-acid acetylated peptide originally isolated from thymus tissue. It modulates the innate and adaptive immune system, with reported effects on dendritic-cell maturation, regulatory T-cell function, and natural killer cell activity. Licensed in several jurisdictions including Italy, China, and across Latin America under the brand name Zadaxin for chronic hepatitis B and adjunct cancer indications. Not licensed in the UK. UK availability is research-tier through research peptide retailers.
What the molecule is
- · 28-amino-acid acetylated peptide originally isolated from thymus tissue (Goldstein AL group).
- · Naturally circulates in human plasma.
- · Modulates dendritic-cell maturation, T-cell function, and innate immune activity.
- · Licensed in over 35 countries under the brand name Zadaxin (SciClone Pharmaceuticals).
What the literature shows
- · Clinical trial data in chronic hepatitis B (multiple Phase III, Italian and Chinese cohorts).
- · Adjunct trial data in melanoma, hepatocellular carcinoma, and severe sepsis.
- · Mechanism work on TLR9 and TLR2 receptor activation pathways.
- · No UK or US FDA marketing authorisation.
UK regulatory status
- · Not a controlled drug under the Misuse of Drugs Act 1971.
- · Not scheduled under the Psychoactive Substances Act 2016.
- · No UK marketing authorisation as a medicine.
- · Licensed in over 35 other jurisdictions but not in the UK.
- · Research-use-only framing required for UK sale.
Where UK researchers source Thymosin alpha-1
See PeptideClear Trust Index →Ranked by CoA Trust tier (strong, partial, weak). Editorial commentary on retailers that list Thymosin alpha-1 or compounds in the same category. We take no commission, referral fee or payment from anyone listed here.
Researchers wanting named-stack bundles (Wolverine, KLOW, Glow) and CoAs that can be QR-verified to a named third-party lab.
Research peptide retailer · Wolverine Stack £29.99, BPC-157 single from £14.99
Nottingham-based research peptide retailer (Bio Research Ltd, since 2024). Bundles and stacks are the hero SKU (Wolverine BPC-157 + TB-500, Tesamorelin + Ipamorelin 3:1, KLOW, Glow). Janoshik third-party CoAs published per batch with QR-code verification. 10-vial bulk packs alongside singles. Wholesale tier above 11 vials.
Researchers who want transparent third-party HPLC batch documents and a less hyped brand voice.
Research peptide retailer · Per peptide, varies
UK research peptide retailer with third-party HPLC plus transparent batch documentation. Plays the credibility lane alongside Pure Peptides UK and Tide Labs.
Best for HPLC verification per product
Research peptide retailer · Per peptide, varies
UK research peptide retailer with HPLC-verified purity claims and CoAs included on orders. Operates under research-use-only framing.
Best for per-batch CoA library
Research peptide retailer · BPC-157 5mg £13.99, TB-500 5mg £36
Long-established UK research peptide supplier. 12 years trading, 15,000+ customers. Operates a public CoA subdomain (coa.purepeptidesuk.com) with downloadable per-batch certificates linked from every PDP. Dual-tier purity (Standard vs Premium with endotoxin LAL + heavy-metal testing on Premium).
Best for public per-batch third-party test reports you can view before ordering
Research peptide retailer · Per peptide, varies
UK-based research peptide retailer trading as Midshire Labs Ltd, with a recovery and longevity focused range, 99%+ purity claims and a public bank of per-batch third-party test reports. All products are framed as research use only.
Researchers who weight UKAS lab accreditation specifically and want the loudest external-verification claim in the segment.
Research peptide retailer · Per peptide, varies
UK research peptide retailer leaning on UKAS-verified HPLC as the sole-in-UK trust claim. Narrower catalogue than UKPeptides or Pure Peptides UK but the lab-verification angle is the loudest in the segment.
Where to learn more
- · PubMed search: "Thymosin alpha-1" and "Zadaxin clinical trial".
- · Goldstein AL research group historical publications.
- · SciClone Pharmaceuticals published trial data.
- · Our function hub: Longevity peptides.
Clinical evidence record
Read the clinical evidence record for Thymosin alpha-1
Top peer-reviewed citations, mechanism of action, structured UK regulatory status. Machine-readable companion to this encyclopedia entry.
PeptideClear does not sell, dispense, prescribe, or recommend Thymosin alpha-1 for any specific person. This page is editorial commentary on the published preclinical and clinical research literature and the UK retail landscape.
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