Thymosin Alpha-1 (TA-1) has more clinical history than almost any peptide in the research market — approved as a drug in 35+ countries, used by functional medicine physicians worldwide for immune optimization, and studied for its role in longevity and immune aging. We compare current research-grade prices across available suppliers.
| Supplier | Size | Price | Price / mg | Notes |
|---|---|---|---|---|
| Swiss Chems Check First | 1mg | ~$28–$35 Est. | ~$28–$35/mg | Historically competitive on immune peptides — verify current availability |
| Spectrum Peptides | 1mg | ~$30–$40 Est. | ~$30–$40/mg | Availability varies — check current stock |
| Peptide Lab | 1mg | ~$35–$50 Est. | ~$35–$50/mg | Broader peptide catalog — likely to carry TA-1 |
| Behemoth Labz | 1mg | ~$35–$55 Est. | ~$35–$55/mg | Large catalog — verify TA-1 specifically is stocked |
Thymosin Alpha-1 is a 28-amino acid peptide naturally produced by the thymus gland — the organ responsible for T-cell maturation and immune education. It was isolated and characterized in the 1970s by Allan Goldstein and colleagues at George Washington University as part of broader thymosin fraction 5 research. The synthetic version has since become one of the most extensively studied peptides in clinical immunology.
Unlike most peptides in the research market, TA-1 has decades of human clinical trial data behind it. It is approved as Zadaxin by SciClone Pharmaceuticals in more than 35 countries, including Italy, China, Singapore, the Philippines, and across Southeast Asia, for chronic hepatitis B, hepatitis C (with interferon), and as an immune adjuvant in cancer care. This clinical pedigree distinguishes it sharply from newer, less-studied compounds.
Thymosin Alpha-1 has a distinctive user profile that sits squarely in the wellness and longevity niche — not the bodybuilding world. It is used by:
Functional medicine physicians — for patients with chronic immune dysregulation, recurrent infections, or persistent fatigue following illness. TA-1 is a standard tool in many integrative medicine immune restoration protocols.
Longevity-oriented individuals — thymic involution (shrinkage) begins in the 20s and accelerates after 40, progressively reducing naive T-cell production. TA-1 is studied as a potential way to partially counteract this immune aging process.
Post-COVID and long-illness recovery — the long COVID community has developed significant interest in TA-1 following research and clinical reports suggesting it supports immune reconstitution after viral immune derangement.
Cancer support — in countries where Zadaxin is approved, it is used as an immunotherapy adjuvant alongside chemotherapy and checkpoint inhibitors, potentially improving immune response to treatment.
Most likely to offer competitive pricing on TA-1 among established Western research suppliers. Check current stock — availability can be intermittent given limited synthesis volume.
Visit Swiss Chems →Broad catalog with generally competitive pricing. TA-1 availability is not guaranteed on any given month — verify before ordering.
Visit Spectrum Peptides →Large peptide catalog; one of the more likely sources for less common peptides like TA-1. Pricing tends to run slightly higher than Spectrum or Swiss Chems.
Visit Peptide Lab →TA-1 is carried by fewer Western suppliers than mainstream peptides. If it's not in stock at the above, check back in 2–4 weeks — specialty peptide stock rotates frequently.
Research-grade TA-1 in 2026 runs approximately $28–$55 per 1mg vial depending on supplier. At a standard research protocol of two 1mg doses per week, monthly cost is roughly $225–$440. This is higher per-mg than shorter peptides like BPC-157 or Epithalon, reflecting the synthesis complexity of a 28-amino acid sequence and limited Western supplier availability. Pharmaceutical Zadaxin (1.6mg) costs significantly more in clinical settings internationally.
Zadaxin is the pharmaceutical brand name for Thymosin Alpha-1, approved in 35+ countries. The active compound is identical — synthetic Thymosin Alpha-1 — but Zadaxin is manufactured under pharmaceutical GMP standards and approved for specific human indications. Research-grade TA-1 from research suppliers is the same peptide sequence made for laboratory research and is not approved for human use in the US. The Zadaxin approval history provides significantly more human clinical data for TA-1 than exists for virtually any other peptide in the research market.
The thymus gland — responsible for T-cell education and immune competence — begins shrinking (involuting) in the mid-20s and has typically lost 70–90% of its functional tissue by age 70. This decline is associated with reduced naive T-cell output, impaired immune surveillance, and increased vulnerability to infections, cancer, and chronic inflammation. TA-1 research explores whether exogenous thymic peptide signaling can partially compensate for this age-related immune decline, supporting more youthful immune function in older individuals.
TB-500 (Thymosin Beta-4) and Thymosin Alpha-1 share a thymosin family name but work through completely different mechanisms. TB-500 is primarily a tissue repair and healing peptide — it promotes cell migration, angiogenesis, and wound healing. Thymosin Alpha-1 is an immune-modulating peptide that works on T-cell maturation and immune balance. They are not interchangeable. TA-1 is the appropriate choice for immune optimization; TB-500 for tissue repair and recovery.
Not in the United States. Zadaxin has not received FDA approval, though it has been used under compassionate use protocols. It is approved in 35+ other countries with strong regulatory systems. In the US, research-grade TA-1 is sold for laboratory research purposes only. Prior to the FDA's April 2026 reclassification, it was available through some 503A compounding pharmacies by physician prescription. Always work with a licensed healthcare provider for personal use guidance.
We'll email you when Thymosin Alpha-1 drops below your target price at any tracked supplier.