For Research Purposes Only. This page summarizes published preclinical and clinical research. It does not constitute medical advice and is not a recommendation for human use.
Thymosin Alpha-1
28-amino-acid thymic peptide that modulates T-cell, dendritic cell, and NK-cell function. Approved in 30+ countries (as Zadaxin), though not by the FDA.
01 · What is Thymosin Alpha-1?
Thymosin Alpha-1 is a 28-amino-acid peptide originally isolated from thymosin fraction 5 of the thymus gland. It modulates immune function — including T-cell maturation, dendritic cell activity, and cytokine signaling — and is approved in over 30 countries under the name Zadaxin for hepatitis B and C and as an immune adjuvant. It has not received FDA approval in the United States; research-grade material is sold as a laboratory reagent.
Sizes currently sold by tracked vendors: 100mg, 10MG, 10mg, 11.68mg, 20mg, 2mg, 500mg, 50mg, 5mg.
02 · Price comparison
Prices last checked Oct 26, 2026| Vendor | Sizes | Price range | Best $/mg | Stock |
|---|---|---|---|---|
| Swiss Chems | 2 | $63.99 – $639.90 | $1.28 | In stock |
| Reta-Peptide | 1 | $175.00 | $1.75 | In stock |
| SaiyanMed | 2 | $105.00 – $206.00 | $2.06 | In stock |
| HkRoids | 2 | $126.00 – $220.00 | $2.20 | In stock |
| Nexaph | 1 | $288.00 | $2.88 | In stock |
| Peptide Partners | 3 | $98.00 – $370.00 | $3.70 | Out of stock |
| NextechLabs | 1 | $42.25 | $4.22 | In stock |
| Royal Peptides | 3 | $55.00 – $480.00 | $4.80 | In stock |
| Peptidology | 2 | $69.00 – $69.99 | $5.91 | In stock |
| Go Alpha Labs | 2 | $41.99 – $314.99 | $6.30 | In stock |
| Oasis Labs | 1 | $65.00 | $6.50 | In stock |
| Hydro Research | 1 | $65.00 | $6.50 | In stock |
| Behemoth Labz | 2 | $84.86 – $326.04 | $6.52 | In stock |
| Amino Amigos | 1 | $75.00 | $7.50 | In stock |
| Loti Labs | 1 | $79.99 | $8.00 | In stock |
| Injectify | 1 | $81.99 | $8.20 | In stock |
| Simple Peptide | 1 | $86.00 | $8.60 | In stock |
| Verified Peptides | 1 | $96.00 | $9.60 | In stock |
| Paramount Peptides | 1 | $97.75 | $9.78 | In stock |
| Umbrella LabsVerified | 3 | $44.99 – $119.99 | $12.00 | In stock |
| Raw AminoVerified | 2 | $69.00 – $120.00 | $12.00 | In stock |
| Biolongevity Labs | 1 | $129.97 | $13.00 | Out of stock |
| Biotech Peptides | 1 | $130.00 | $13.00 | In stock |
| Steady Meds | 2 | $75.00 – $135.00 | $13.50 | In stock |
| Core Peptides | 2 | $81.00 – $149.00 | $14.90 | In stock |
| Mei Peptide | 3 | $55.00 – $170.00 | $17.00 | In stock |
| Nextwave Peptides | 2 | $147.00 – $221.00 | $22.10 | In stock |
27 vendors tracked · prices scraped weekly from vendor sites · open full comparison table →
03 · Third-party purity data
Full data at peptigrity.com ↗Independent HPLC test results — averages across multiple samples.
04 · Frequently asked questions
What is Thymosin Alpha-1?
Thymosin Alpha-1 is a 28-amino-acid peptide originally isolated from thymosin fraction 5 of the thymus gland. It modulates immune function — including T-cell maturation, dendritic cell activity, and cytokine signaling — and is approved in over 30 countries under the name Zadaxin for hepatitis B and C and as an immune adjuvant.
Is Thymosin Alpha-1 FDA approved?
Not by the FDA — but it is approved in more than 30 other countries (as Zadaxin) for hepatitis B/C and immune indications. Research-grade vials sold by peptide vendors are not the pharmaceutical product.
How much does Thymosin Alpha-1 cost?
Across 27 vendors tracked by PepVendors, Thymosin Alpha-1 currently runs $1.28–$22.10 per mg at each vendor's best price tier (25 showing in stock). Vial prices and size tiers vary — the live comparison table on this page lists current pricing.
Which vendors have third-party purity data for Thymosin Alpha-1?
Independent labs (Finnrick Analytics, Janoshik) have published HPLC purity results for 20 samples of Thymosin Alpha-1 or its components: Biotech Peptides (100.0%), Oasis Labs (99.9%), Biolongevity Labs (99.8%), Injectify (99.7%), UWA Elite Peptides (99.7%), Nexaph (99.7%), Loti Labs (99.6%), Peptidology (99.6%), Limitless Life (99.6%), Verified Peptides (99.6%), Polaris Peptides (99.6%), Core Peptides (99.5%), HkRoids (99.5%), Simple Peptide (99.5%), Royal Peptides (99.4%), Umbrella Labs (99.3%), Amino Amigos (99.3%), Hydro Research (99.2%), Liberty Peptides (99.1%), Go Alpha Labs (97.8%). A grade A (≥98%) is the appropriate baseline for research use — check the linked lab reports for batch-level detail and fill-accuracy data.