Thymosin Alpha-1 – 5MG / 10MG

What Is Thymosin Alpha-1?

Thymosin Alpha-1 peptide, also known as Thymosin Alpha, TA1, or T α 1, is a fragment of a protein molecule that has been widely studied for its potential implications with the immune system. Researchers have hypothesized that it contributes to the production of T-cells to mitigate and alleviate infection and bacterial spread.⁽¹⁾

Thymosin Alpha-1 is a naturally occurring polypeptide that is considered by researchers to potentially restore and enhance immune functions.⁽²⁾ Thymosin Alpha-1 is considered to be one of the polypeptides found in Thymosin Fraction 5, which is a crude extract of the thymus gland.⁽³⁾

Since its discovery, a synthetically developed form of Thymosin Alpha-1 has also been studied, researchers refer to the peptide as Thymalfasin.⁽²⁾ Thymalfasin is composed of 28 amino acids, similar to the naturally occurring Tα 1, and is derived from a longer polypeptide precursor composed of 113 amino acids, known as Prothymosin Alpha.⁽³⁾

 

How Is Thymosin Alpha-1 Thought to Work?

The main aim of initial research into Thymosin Alpha-1⁽⁴⁾ was to understand and examine the immunomodulating potential of the peptide. Studies have suggested that the peptide may increase the concentration of the major histocompatibility complex (MHC) class I and cytokine production, which may possibly lead to increased immune responses. The peptide may also enhance the activity of natural killer cells and foster the expression of phenotypic markers on T cells, suggesting a multi-faceted role in modulating the immune response. The researchers posited that the peptide may also increase the expression of high-affinity receptors for interleukin-2. This could potentially lead to a more vigorous activation and proliferation of T lymphocytes.

Researchers speculate that Thymosin Alpha-1 may stimulate possible action by targeting the T-helper cells and cytotoxic T-cell populations.⁽³⁾ Tα 1 may possibly induce differentiation of the T-cells (thymocytes) and the terminal differentiation of the blood lymphocytes. Scientists posit that it may elevate the production of the natural killer cells and potentially stimulate cytokine mediated inflammation.⁽²⁾⁽³⁾ Furthermore, the peptide has been studied for its potential to enhance efficiency of macrophages and functions as the modulator of the alpha thrombin activity.⁽³⁾

 

Thymosin Alpha-1 Specifications

Name	Thymosin Alpha-1
Other known names	Thymalfasin, TA1, Tα1
Sequence	Ac-Ser-Asp-Ala-Ala-Val-Asp-Thr-Ser-Ser-Glu-Ile-Thr-Thr-Lys-Asp-Leu-Lys-Glu-Lys-Lys-Glu-Val-Val-Glu-Glu-Ala-Glu-Asn-OH (28 amino acids)
Molecular formula	C129H215N33O55
Molecular weight	3108.31 g/mol
CAS number	62304-98-7
Synthesis	Solid-phase peptide synthesis, US
Form	Lyophilized powder
Amount per vial	5 mg or 10 mg
Purity	>99% (HPLC)
Storage	−20 °C, dry, protected from light
SKU	P-THYMOSA1-5-10

 

What Does Research Show About Thymosin Alpha-1?

How May Thymosin Alpha-1 Affect the Immune System in Research?

Key finding: In laboratory (in vitro) tests on cells from 11 subjects with primary immunodeficiencies, Thymosin Alpha-1 improved low lymphokine-activated killer (LAK) cell activity up to 25–30% in three subjects, but did not affect the moderately reduced activity seen in common variable immunodeficiency.⁽⁵⁾

In an in vitro cell study,⁽⁵⁾ 11 cell cultures of different immune system dysfunctions were evaluated for the levels of their natural killer (NK) and lymphokine activated killer cells (LAK) present. It was noted that the immunodeficient cells demonstrated the mean LAK-cell activity of approximately 65% as compared to the control cultures. Upon presenting Thymosin Alpha-1 to the cultures, researchers observed that it did not significantly improve the levels of NK or LAK cells. Only 3 cell cultures were reported to exhibit improved LAK-cell activity by up to 30% whereas others were not significantly impacted.

What Does Research Show About Thymosin Alpha-1 and Hepatitis?

Key finding: A 2020 literature review reports a complete virological response rate of 40.6% in hepatitis B models exposed to Thymosin Alpha-1, while Thymosin Alpha-1 alone did not appear impactful against hepatitis C.⁽²⁾

Clinical trials were conducted in test subjects with liver complications, with some exhibiting Hepatitis B & C. Tα 1 was presented to the subjects to explore its potential mechanism of action on these complications.⁽²⁾ For subjects exhibiting Hepatitis B, it was reported by the research team that when these subjects were presented with Thymosin Alpha-1 twice a week for the duration of the study, a virological response rate of 40.6% was reported. For Hepatitis C, subjects reportedly exhibited improved results when Tα 1 was present in combination with interferon alpha compounds. Thymosin alpha-1's apparent role in modulating the immune system was further explored through its potential engagement with toll-like receptors (TLR)-2 and TLR-9 on dendritic cells and other antigen-presenting cells. This interaction potentially initiates a cascade of immune responses, including the stimulation of cytokines such as interleukin-2 (IL-2), IL-10, and interferon-gamma (IFN-γ), which in turn may support the adaptive immune system. Such modulation is crucial not just for combating infections but also for controlling inflammatory responses, potentially benefiting chronic hepatitis and acute pancreatitis due to its apparent actions on cytokine profiles. In murine models and in vitro studies, Thymosin alpha-1 has been shown to possibly stimulate T-cell maturation and enhance the efficacy of natural killer cells. It might also play a role in reducing inflammatory cytokines such as tumor necrosis factor-alpha, which could be particularly beneficial in chronic inflammatory models.

What Does Research Show About Thymosin Alpha-1 and Sepsis?

Key finding: A meta-analysis of 12 controlled trials with 1,480 sepsis models found that Thymosin Alpha-1 was associated with lower all-cause mortality (pooled risk ratio 0.68); the authors noted that the trials were small and of poor quality.⁽⁶⁾

In a 2015 study,⁽⁶⁾ a meta-analysis was conducted where all the relevant clinical trials prior to 2014 were analyzed to understand the possible mechanism of Thymosin Alpha-1 in relation to the sepsis reaction. In this study, 12 controlled trials were evaluated in total. Based on the extracted data and assessment, it was observed by the research analysts that there was a reported significant decline in mortality rate amongst test subjects following introduction to Thymosin Alpha-1. Subsequent studies and systematic reviews, such as those conducted by Yu et al., have supported the hypothesis that Tα1 could alleviate the immunosuppression associated with severe sepsis. However, all these studies were conducted on an exceedingly small pool of test subjects. Given the complex immune dynamics during sepsis, characterized by an initial hyperinflammatory response followed by a phase of immunosuppression, it is plausible that Tα1's potential could be highly dependent on the timing of exposure. Addressing this aspect, further investigations are required to establish a more detailed understanding of how Tα1 influences immune pathways during different stages of sepsis.

What Does Research Show About Thymosin Alpha-1 and HIV?

Key finding: In a 12-week study of 20 HIV models of low CD4 counts on antiretroviral therapy, Thymosin Alpha-1 did not change CD4, CD8 or CD45 subsets compared with controls, but significantly increased sjTREC levels, which the authors suggest may reflect enhanced immune reconstitution.⁽⁷⁾

A study⁽⁷⁾ consisted of a randomized phase II open-label clinical trial on 20 clinically stable test subjects. These patients were already undergoing highly active antiretroviral (HAART), alongside which Thymosin Alpha-1 peptide was presented to monitor the impact of the combination. Thymosin Alpha-1 was presented two times in a week in 13 subjects. The remaining 7 subjects served as controls. Every 2 weeks, the cell counts of CD4/CD8 cells, CD45 cells and signal joint T-cell receptor circles (sjTREC) levels were monitored. After 12 weeks, it was reported by the researchers that there were no apparent significant changes in the levels of CD4, CD8 and CD45 levels in both the peptide or the control group. However, the sjTREC levels reportedly increased in the subjects presented with the peptide. These elevated levels of sjTREC might potentially stimulate immune responses. This increase in sjTREC levels hints at the possibility that Thymosin Alpha-1 may contribute to immune reconstitution by enhancing thymic output. However, this change did not correspond with an increase in total T-cell numbers or significant changes in the proportions of naive and memory T-cell phenotypes. Researchers posited that while the rise in sjTREC levels might indicate a modest improvement in thymopoiesis, the overall recovery and functionality of the T-cell compartment appeared largely unchanged within the duration of this study.

How May Thymosin Alpha-1 Affect Cancer Cells in Laboratory Studies?

Key finding: In laboratory studies, Thymosin Alpha-1 raised ROS levels in mouse spleen leukomonocytes, while in human HepG2 liver cancer cells it lowered ROS, delayed the cell cycle in the G1 phase and reduced proliferation, with dephosphorylation of Akt.⁽⁸⁾

In a study,⁽⁸⁾ the levels of the reactive oxygen species (ROS) were monitored in test models after the presentation of Tα 1. In the study by Qin et al. (2009), Thymosin Alpha-1 was tested in two separate cell models, including murine splenic leukomonocytes isolated from mouse spleens and the hepatocellular carcinoma cell line HepG2. Apparently, the peptide increased proliferation of the splenic leukomonocytes but inhibited proliferation of HepG2 cells. Upon analysis, it was observed by the researchers that the ROS level appeared to be significantly higher in the isolated leuko-monocytes, whereas it was apparently lower in the HepG2 cells. Also, the peptide appeared to possibly increase the levels of the leuko-monocytes, whereas it may have delayed the cell cycle for HepG2 cells and thereby reduced their levels in the system. The study also delved into the possible molecular pathways affected by these changes in the redox state. Particularly, the Akt signaling pathway, known to be influenced by ROS, was examined. It was found that in HepG2 cells, there was a dephosphorylation of Akt at Ser473 following Tα1 exposure, suggesting a decrease in Akt activity associated with lowered oxidative stress. This dephosphorylation of Akt might underpin the reduced proliferation seen in these cancer cells.

Another laboratory study focused on lung cancer cells (A549), in order to investigate the potential of Thymosin Alpha-1 on cell proliferation, antioxidant enzyme activities, and cell migration.⁽⁹⁾ The study's findings suggest that Thymosin Alpha-1 potentially exhibits an anti-proliferative action on A549 cells, particularly at concentrations of 24 and 48 μg/mL, which apparently led to a reduction in cell viability after 24 hours of exposure. Additionally, Thymosin Alpha-1 is posited to enhance the activity of several key antioxidant enzymes. For instance, increases in the activity levels of catalase were observed at concentrations of 12 μg/mL, suggesting a possible strengthening of the cells' oxidative stress response. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) also showed possible enhancements at concentrations of 6 and 12 μg/mL. These findings indicate that Thymosin Alpha-1 might contribute to the cellular antioxidant defense by mitigating the adverse actions of reactive oxygen species (ROS). Regarding cell migration, Thymosin Alpha-1 potentially inhibits the migration of A549 cells in a concentration-dependent manner, as indicated by scratch assays. In terms of ROS production, the study suggests that Thymosin Alpha-1 might lead to a reduction in cellular ROS levels, and this outcome further supports the notion that Thymosin Alpha-1 could play a role in moderating oxidative stress within cancer cells.

 

Thymosin Alpha-1 Certificate of Analysis

Size	5mg	10mg
Batch / lot	C74186	C74201
Test date	8/21/2026	7/15/2026
Testing laboratory	Vanguard Laboratory	Vanguard Laboratory
Method	HPLC-UV/VIS (identity and purity)	HPLC-UV/VIS (identity and purity)
Purity result	99.22%	99.08%
Full report	Download the Thymosin Alpha-1 5mg COA (PDF)	Download the Thymosin Alpha-1 10mg COA (PDF)

Thymosin Alpha-1 peptide is available for research and laboratory purposes only. We offer free shipping in the US for orders over $200. Please review our Terms and Conditions before ordering.

 

Thymosin Alpha-1 Frequently Asked Questions

 

References:

1. British Society for Immunology. (2017, March). Immunodeficiency [Briefing]. https://www.immunology.org/policy-and-public-affairs/briefings-and-position-statements/immunodeficiency
2. Dominari, A., Hathaway Iii, D., Pandav, K., Matos, W., Biswas, S., Reddy, G., Thevuthasan, S., Khan, M. A., Mathew, A., Makkar, S. S., Zaidi, M., Fahem, M. M. M., Beas, R., Castaneda, V., Paul, T., Halpern, J., & Baralt, D. (2020). Thymosin alpha 1: A comprehensive review of the literature. World journal of virology, 9(5), 67–78. https://doi.org/10.5501/wjv.v9.i5.67
3. National Center for Biotechnology Information (2023). PubChem Compound Summary for CID 16130571, Thymalfasin. PubChem. https://pubchem.ncbi.nlm.nih.gov/compound/Thymalfasin
4. Garaci, E. (2007). Thymosin alpha1: a historical overview. Annals of the New York Academy of Sciences, 1112, 14–20. https://doi.org/10.1196/annals.1415.039
5. Eckert, K., Schmitt, M., Garbin, F., Wahn, U., & Maurer, H. R. (1994). Thymosin alpha 1 effects, in vitro, on lymphokine-activated killer cells from patients with primary immunodeficiencies: preliminary results. International journal of immunopharmacology, 16(12), 1019–1025. https://doi.org/10.1016/0192-0561(94)90081-7
6. Li, C., Bo, L., Liu, Q., & Jin, F. (2015). Thymosin alpha1 based immunomodulatory therapy for sepsis: a systematic review and meta-analysis. International journal of infectious diseases, 33, 90–96. https://doi.org/10.1016/j.ijid.2014.12.032
7. Chadwick, D., Pido-Lopez, J., Pires, A., Imami, N., Gotch, F., Villacian, J. S., Ravindran, S., & Paton, N. I. (2003). A pilot study of the safety and efficacy of thymosin alpha 1 in augmenting immune reconstitution in HIV-infected patients with low CD4 counts taking highly active antiretroviral therapy. Clinical and experimental immunology, 134(3), 477–481. https://doi.org/10.1111/j.1365-2249.2003.02331.x
8. Qin, Y., Chen, F. D., Zhou, L., Gong, X. G., & Han, Q. F. (2009). Proliferative and anti-proliferative effects of thymosin alpha1 on cells are associated with manipulation of cellular ROS levels. Chemico-biological interactions, 180(3), 383–388. https://doi.org/10.1016/j.cbi.2009.05.006
9. Kharazmi-Khorassani, J., & Asoodeh, A. (2019). Thymosin alpha-1; a natural peptide inhibits cellular proliferation, cell migration, the level of reactive oxygen species and promotes the activity of antioxidant enzymes in human lung epithelial adenocarcinoma cell line (A549). Environmental toxicology, 34(8), 941–949. https://doi.org/10.1002/tox.22765

Related reading: Thymosin Alpha-1 research into immune cell development.

Last updated Oct 15, 2026 · Scientific review: Dr. Dimitar Marinov, MD, PhD