For research use only. Not for human consumption. Not medical advice — consult a licensed clinician.

Immune Modulator

Thymosin Alpha-1

Also known as: Thymalfasin (trade name Zadaxin)

Thymosin Alpha-1 (Ta1) is a 28-amino-acid thymic peptide (Ac-SDAAVDTSSEITTKDLKEKKEVVEEAEN) approved as Zadaxin in 35+ countries for chronic hepatitis B/C and as an immune adjuvant. It is NOT FDA-approved in the US.

Where to buy · live market data

Who's worth your money for Thymosin Alpha-1

Every current seller, ranked by independent evidence — Merit Score, latest COA purity, and live $/mg (size-normalized). Prices refresh daily. Rankings are never paid.

Top Merit pick

🇺🇸 Glacier Aminos 99

Highest Merit Score (99) of 36 scored sellers

$6.40/mg

$63.99 · 10mg · 99.7% purity

6 COAs
Buy Code MERIT · 10% off

Best value

🇺🇸 Peptidology 89

Lowest $/mg among scored sellers

$1.03/mg

$69.99 · 68mg · 99.8% purity

3 COAs
Buy

Most tested

🇺🇸 Verified Peptides 87

21 independent COAs on file

$8.00/mg

$80.00 · 10mg · 99.6% purity

21 COAs
Buy

Average price

$8.20/mg

Sellers

61

45-day trend

-16%

43 of 61 sellers have a current price· 2 stale hidden· 5 unverified hidden

Prices observed from public storefronts (last 24h), normalized to $/mg. "Evidence" is Merit's 0–100 Merit Score, derived only from observable verification evidence (methodology on /about); "Purity" is the latest independent COA. Some buy links are affiliate links — Merit may earn a commission at no extra cost to you, and where a vendor offers one, the code shown gets you a discount at their checkout. Affiliate status never affects price data, ranking, or the Merit Score (full policy on /disclosure). Research use only.

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Compound reference

About Thymosin Alpha-1

CAS

62304-98-7

Molecular formula

C129H215N33O55

Sequence

SDAAVDTSSEITTKDLKEKKEVVEEAEN

Typical dose range

1.6 mg subcutaneous 2–3x/week (clinical standard); research protocols range 1.6–6.4 mg per dose

Half-life

~2–3 hours (subcutaneous; elimination t½ <3 h confirmed by PK study)

Independent evidence

COAs for Thymosin Alpha-1

124 third-party tests across 33 vendors. Each card links to the full report.

All 124 COAs for Thymosin Alpha-1 →
Measured purity 98.9%–100.0% across 93 COAs
Measured purity over time
Aggregated · 3rd-party listing
99.39 %
Jul 2026
Horizon Analytical

For

Thymosin Alpha-1

by Blank Peptides· batch DPS-8269267

Aggregated · 3rd-party listing
99.47 %
Jul 2026
ILS Labs Strong

For

Thymosin Alpha-1

by NG Peptide· batch TA1-05

Aggregated · 3rd-party listing
99.00 %
Jun 2026
Ethos Analytics Strong

For

Thymosin Alpha-1

by OROS Research· batch OR-LPTA5-626-B2

Aggregated · 3rd-party listing
99.65 %
Jun 2026
Janoshik Analytical Limited

For

Thymosin Alpha-1

by EZ Peptides· batch EZP-TA11006052026-04

Aggregated · 3rd-party listing
99.85 %
Jun 2026
Freedom Diagnostics Moderate

For

Thymosin Alpha-1

by Modern Research Peptides· batch 982444TU

Aggregated · 3rd-party listing
99.56 %
Jun 2026
Janoshik Analytical Limited

For

Thymosin Alpha-1

by Verified Peptides· batch TA05260910H

Aggregated · 3rd-party listing
99.61 %
May 2026
Freedom Diagnostics Moderate

For

Thymosin Alpha-1

by Blank Peptides· batch THYMA10-052026-7

Aggregated · 3rd-party listing
100.00 %
May 2026
Prime Analytical Laboratories, LLC

For

Thymosin Alpha-1

by Soma Peptides· batch TAXV042603

Aggregated · 3rd-party listing
99.57 %
May 2026
Janoshik Analytical Limited · HPLC

For

Thymosin Alpha-1

by Skye Peptides· batch TA126-10-001

Aggregated · 3rd-party listing
99.68 %
May 2026
Freedom Diagnostics Moderate

For

Thymosin Alpha-1

by Real Peptides· batch Black Cap

Aggregated · 3rd-party listing
99.32 %
Apr 2026
Horizon Analytical

For

Thymosin Alpha-1

by Pepsgpt· batch P-1947064-P

Aggregated · 3rd-party listing
98.89 %
Apr 2026
ILS Labs Strong

For

Thymosin Alpha-1

by Riptide Wellness· batch RWTA1-10-1003

✓ Vendor-published
99.98 %
Apr 2026
Kovera Labs

For

Thymosin alpha-1

by Ion Peptide· batch TA110-04202026

COA on file
Aggregated · 3rd-party listing
99.58 %
Apr 2026
Freedom Diagnostics Moderate · HPLC

For

Thymosin Alpha-1

by Peptide Supply Co.· batch TA1004132026

Aggregated · 3rd-party listing
99.00 %
Apr 2026
Ethos Analytics Strong · HPLC

For

Thymosin Alpha-1

by OROS Research· batch OR-LPTA5-326-B1

Aggregated · 3rd-party listing
99.81 %
Apr 2026
Janoshik Analytical Limited · HPLC

For

Thymosin

by Verified Peptides· batch cmojb57q300trkirxximley58

Aggregated · 3rd-party listing
99.91 %
Apr 2026
Biogenica Labs · HPLC

For

Thymosin Alpha-1

by Amino Club· batch THA0001

Aggregated · 3rd-party listing
99.97 %
Mar 2026
Kovera Labs

For

Thymosin alpha-1

by Ion Peptide· batch TA110-03232026

✓ Vendor-published
99.97 %
Mar 2026
Kovera Labs

For

Thymosin alpha-1

by Ion Peptide· batch TA110-03232026

COA on file
Aggregated · 3rd-party listing
99.92 %
Mar 2026
Freedom Diagnostics Moderate

For

Thymosin Alpha-1

by Modern Research Peptides· batch MKUST5WC3526

Aggregated · 3rd-party listing
99.75 %
Mar 2026
Janoshik Analytical Limited · HPLC

For

Thymosin Alpha-1

by Profound Aminos· batch cmojb89io01hzkirx1zv5axqw

Aggregated · 3rd-party listing
99.39 %
Mar 2026
Janoshik Analytical Limited · HPLC

For

Thymosin Alpha-1

by Verified Peptides· batch TA032608106

Aggregated · 3rd-party listing
99.95 %
Feb 2026
Kovera Labs · HPLC

For

Thymosin Alpha-1

by Peptide Partners· batch TA202602

✓ Vendor-published
99.95 %
Feb 2026
Kovera Labs

For

Thymosin alpha-1

by Peptide Partners· batch TA202602

COA on file
Research depth

20 citations indexed for Thymosin Alpha-1

All research on Thymosin Alpha-1 →

Study · 2026

Thymosin Alpha-1 Provides Direct Neuroprotection by Engaging the Orexin Receptor HCRTR1 to Suppress Neuronal Necroptosis

Communication between the immune system and the brain is critical for neuronal health, yet the molecular signals that mediate this crosstalk are not fully understood. Here, we uncover an unexpected and direct neuroprotective axis linking the thymus to the central nervous system (CNS).

Study · 2026

Thymosin Alpha-1 Restores Chemotherapy-Induced Antitumor Immunity by Chaperoning a MicroRNA Ligand of TLR7 in Dendritic Cells

Chemotherapy induces cancer cell apoptosis and the release of apoptotic bodies (AB) that are poorly immunogenic or immunosuppressive, creating a major barrier to the success of coadministered or second-line immunotherapies.

Study · 2026

A Case Report of a Multisystemic Immune-Related Adverse Event Caused by Sintilimab in Combination With Thymosin Alpha-1

To report a case of a nasopharyngeal carcinoma patient who developed multisystem immune-related adverse events (irAEs) after treatment with sintilimab (PD-1 inhibitor) in combination with thymosin alpha-1 (Tα1). The patient presents with high fever, rash, interstitial pulmonary edema, and multiple organ failure.

review · 2025

Aging and Thymosin Alpha-1

Aging is characterized by immune decline, mainly due to thymic involution-the age-related shrinkage of the thymus gland. This leads to reduced T-cell production, chronic inflammation, and increased susceptibility to age-related diseases.

Study · 2025

The Immunomodulatory Activity of Thymosin Alpha 1 on Tumor Cell Lines and Distinct Immune Cell Subsets

Background The immune-balancing role of thymosin alpha 1 (Tα1) is well-recognized in contexts of immune dysregulation. Within the anti-tumor context, Tα1 demonstrated to act as an immune-enhancer, with potential roles in immunotherapy-based treatments.

meta-analysis · 2025

Thymosin alpha 1 alleviates inflammation and prevents infection in patients with severe acute pancreatitis through immune regulation: a systematic review and meta-analysis

Background Immune and inflammatory disorders are part of the complex pathophysiological processes that exacerbate severe acute pancreatitis (SAP) and subsequent infection.