What Thymosin Alpha-1 is

Thymosin Alpha-1 belongs to the immunomodulatory-peptide family — a group of compounds developed from research on thymic peptides and short anti-inflammatory sequences. Unlike broad immunosuppressants or immune-stimulators, this class exerts targeted, receptor-mediated modulation of specific immune subsets.

• Thymosin Alpha-1 (Tα1, Zadaxin) is a 28-amino-acid peptide originally isolated from thymus tissue. It is approved for clinical use in over 35 countries (not the U.S.) as an adjunct in chronic hepatitis B and C and in immunocompromised patient protocols.
• KPV is the C-terminal tripeptide of α-MSH (Lys-Pro-Val). Despite its short sequence, it retains substantial anti-inflammatory activity — particularly at intestinal and dermal sites — without α-MSH's pigmentary effect.

Mechanism of action

• Thymosin Alpha-1 — activates TLR2 and TLR9 pathways on plasmacytoid dendritic cells and CD4⁺ T-cells, restoring Th1 cytokine profile in immunocompromised populations. It enhances antigen-specific T-cell response without generalized inflammation.
• KPV — acts on melanocortin-1 receptor (MC1R) and downregulates NF-κB signaling in enterocytes, macrophages, and mast cells. Its anti-inflammatory activity in colitis models is one of the most consistent findings in the α-MSH-fragment literature.

Published research findings

• Thymosin Alpha-1 has published data in HBV/HCV combination therapy, sepsis-adjunct protocols, immunosenescence, and (during 2020-2021) as an off-label adjunct in severe COVID pneumonia (multiple Chinese and Italian case series).
• KPV has published data in DSS-colitis models, atopic-dermatitis models, and oral-inflammation research.

Dosing ranges reported in the literature

• Thymosin Alpha-1: 1.6 mg subcutaneous, dosed twice weekly in HBV/HCV protocols; some immunosenescence protocols dose daily for a loading period.
• KPV: 250–500 µg subcutaneous or oral (with acid protection) daily in research protocols; topical formulations for dermatological research.

Standard laboratory handling

Every research vial from PX1 is a lyophilized (freeze-dried) powder sealed under vacuum in a Type-I borosilicate vial with a butyl-rubber stopper and aluminum crimp seal. Correct handling preserves potency and prevents peptide-bond hydrolysis that degrades the active molecule.

• Storage before reconstitution: 2–8 °C refrigerator is ideal; freezer (−20 °C) for storage beyond six months. Short excursions to room temperature during shipping do not compromise integrity — the compound is stable in its solid state.
• Reconstitution solvent: bacteriostatic water for injection (0.9% benzyl alcohol) is standard for research protocols that require multiple sampling events from the same vial. Sterile water is acceptable for single-use protocols.
• Reconstitution technique: inject the diluent slowly against the vial wall — never directly onto the lyophilized cake. Swirl gently; do not shake. Shaking introduces air, denatures peptide secondary structure, and can create insoluble aggregates.
• Post-reconstitution storage: 2–8 °C refrigerated, typically stable 21–30 days depending on the peptide. Freezing a reconstituted solution repeatedly is not recommended — freeze/thaw cycles are the single biggest driver of loss-of-potency in the research literature.
• Concentration math: volume of diluent (mL) = peptide mass (mg) ÷ desired concentration (mg/mL). Example: 10 mg vial + 2 mL bacteriostatic water = 5 mg/mL.

Purity, identity and COA verification

The single most important due-diligence step when sourcing Thymosin Alpha-1 for research is reviewing the lot-specific Certificate of Analysis (COA). A credible COA contains:

1. HPLC purity value with chromatogram — target ≥ 98% for injectable-grade research peptides; ≥ 99% for the newest generation of GLP/incretin compounds. A single well-defined main peak with baseline separation from impurities is what you are looking for.
2. Identity confirmation by mass spectrometry — LC-MS or MALDI-TOF confirming the observed molecular weight matches the theoretical mass to within instrument tolerance.
3. Endotoxin (LAL / kinetic-chromogenic) result — expressed in EU/mg; USP guidance for parenteral products is well below 5 EU/kg body-weight equivalent, and reputable suppliers report < 10 EU/mg on the COA.
4. Sterility result — USP <71> membrane filtration or direct inoculation, both bacterial and fungal.
5. Karl Fischer moisture — target < 5% residual water for a properly lyophilized cake.
6. Residual-solvent screen — DMF, TFA, DCM, acetonitrile below ICH Q3C thresholds.

PX1 publishes lot-specific COAs at /purity-reports. If you have received a shipment and want to verify the exact lot documentation for Thymosin Alpha-1, cross-reference the lot number on the vial label to the COA PDF.

Why researchers choose PX1 for Thymosin Alpha-1

• 100% U.S. synthesis, lyophilization, and fill/finish. No repackaged imports. Every step from raw amino acid to sealed vial happens under one U.S. GMP-compliant roof.
• Third-party ISO-17025 testing on every lot. Purity, identity, endotoxin, sterility, moisture, and residual-solvent testing performed by an independent analytical laboratory whose data appears on the shipped COA.
• Chain-of-custody documentation from raw material through final QC — the same documentation package a clinical CDMO would provide.
• Same-day shipping on in-stock catalog items ordered before 3 p.m. ET, with insulated packaging and cold-pack where appropriate.

Common researcher questions

Q: How do I know the vial contents match the label? Compare the lot number on the vial to the lot number on the COA. The COA lists HPLC purity, identity by mass-spec, and endotoxin. If any of the three is missing or the lot doesn't match, don't proceed.

Q: Can I use bacteriostatic water past its printed expiration? Bacteriostatic water carries a manufacturer-assigned expiration for the sealed vial. Once punctured, USP guidance limits multi-dose vials to 28 days at 2–8 °C. Beyond 28 days, discard.

Q: Is refrigeration required during shipping? For most lyophilized peptides, no — the solid form is stable at ambient temperature for weeks. Some compounds (IGF-1 LR3, certain GH-releasing peptides) benefit from cold-chain shipping. PX1 uses insulated packaging for temperature-sensitive lines.

Q: What if the reconstituted solution is cloudy? Cloudiness indicates aggregation or precipitation and the solution should not be used. Common causes: over-vigorous shaking, incompatible diluent, or a vial that has passed its stability window.

Research use disclaimer

Thymosin Alpha-1 is supplied to licensed research professionals for in vitro and in vivo laboratory research only. Products are not intended for human consumption, veterinary use, diagnostic use, therapeutic use, or as a food additive or cosmetic. Nothing on this page constitutes medical advice. Consult the primary literature — clinical-trial registrations, peer-reviewed publications — before designing any protocol. Compounds discussed here are investigational; several have not received FDA approval for any indication.

Additional PX1 references

• Complete research library
• Lot-specific purity reports
• Product catalog
• Manufacturing & QC standards