Most used for Most used for Immunity & Infectious Disease.
Thymosin Alpha-1 (TA1) is a 28-amino-acid peptide naturally produced by the thymus gland. It enhances and regulates immune system activity by stimulating T cells, natural killer cells, and macrophages. It has been studied for its role in improving immune function, fighting viral infections such as hepatitis B, and supporting cancer therapy.
Research use only (not for human use)
Restricted / monitored
Thymosin Alpha-1 (TA1) is a synthetic version of a naturally occurring peptide originally isolated from thymosin fraction 5, a substance derived from the thymus gland. It is composed of 28 amino acids and plays a role in modulating immune system activity.
TA1 is purported to enhance immune function by promoting T-cell production and improving immune response efficiency. It has been studied for its potential to support resistance to infections, improve vaccine effectiveness, and aid in immune regulation in various clinical settings.
Thymosin Alpha‑1 (TA1) is primarily recognized for its ability to enhance immune system function. Clinical and preclinical studies have shown that TA1 increases the number and activity of T-cells and natural killer (NK) cells, and it can stimulate dendritic cells and other antigen-presenting cells via toll-like receptors. In patients with chronic viral infections such as HIV or hepatitis, TA1 has been shown to improve immune reconstitution and increase markers of thymic output (signal joint T-cell receptor excision circles) 1. It has also been applied in settings of severe infection or sepsis, where modulation of immune cell subsets and improved immune homeostasis were observed 2. Together, these findings point to TA1’s principal benefit of restoring and enhancing immune competence in compromised individuals.
Beyond immune cell enhancement, TA1 has demonstrated adjunctive benefits in disease-contexts such as cancer and viral infections. In oncology studies, TA1 has been used alongside chemotherapy or immunotherapy, and it has been associated with improved immune profiles, reduced infections during treatment, and in some trials improved survival in non-small cell lung cancer and hepatocellular carcinoma 3. In viral illness settings, TA1 has been reported to act as a vaccine adjuvant improving immunogenicity, and in animal/clinical models to reduce oxidative stress and inflammatory damage in tissues such as the pancreas. It may thus offer both enhancement of immune responses and modulation of the immune-inflammatory environment. Overall, TA1’s main benefits are immune system enhancement and improved immune-inflammatory regulation in a variety of conditions.
Clinical studies of Thymosin Alpha‑1 (TA1) report that the most common adverse effects are mild and injection-site related, such as redness, discomfort, or irritation. In some trials combined with other treatments like interferon, additional effects included fever, fatigue, muscle aches, nausea, vomiting and transient neutropenia 4. Rare reports describe transient muscle atrophy, joint pain with swelling, rash, or a temporary increase in ALT liver enzyme levels 5. Overall, while adverse events occur, they tend to be mild and infrequent in clinical settings.
In one recent large-scale review of over 11,000 human subjects across more than 30 trials, TA1 was described as well-tolerated with a favorable side-effect profile. A sepsis-focused trial listed common adverse effects including anaemia (10.7 %), fever (9.6 %), abdominal distension (5.4 %), and coagulation disorders (4.8 %) in the treatment arm 6, 7. Even so, severe or life-threatening side effects have been very rare overall. In summary, the main negative side effects of TA1 are mild injection site reactions and occasional transient systemic symptoms.
Thymosin Alpha‑1 (Tα1) exerts its effects by binding to and activating toll-like receptors (TLRs), particularly TLR2 and TLR9 on dendritic and myeloid immune cells. This activation triggers downstream signaling via the MyD88 adapter protein and engages NF-κB and p38 MAPK pathways, leading to increased expression of costimulatory molecules (such as CD40 and MHC class I/II) and enhanced antigen-presentation capacity in dendritic cells 8, 9. Tα1 also promotes the production of key cytokines including IL-12, IFN-α and IFN-γ, which support Th1 polarization and bolster CD8+ T cell and NK cell cytotoxic activity against infected or malignant cells. In summary, Tα1 stimulates innate immune sensors, matures antigen-presenting cells, and enhances adaptive cytotoxic immunity via regulated cytokine networks.
It was studied clinically and has orphan designations but no active FDA-approved product. Any current U.S. supply is considered unapproved and limited to research use, not standard prescription use 10. For sports, Thymosin Alpha-1 is not on the World Anti-Doping Agency's (WADA) Prohibited List, but it's important to note that its use by athletes is restricted due to its classification as a peptide hormone. While not explicitly banned, athletes must be cautious, as it could potentially fall under broader categories like "Growth Factors" or other sections of the list, depending on the specific sport and governing body.
