Thymosin Alpha-1 Peptide Therapy | Reviews, Results, and Safety

Thymosin alpha-1 is a research peptide of interest in multiple clinical areas, including hepatology, oncology, immunology, and neurology. It is also undergoing evaluation as a vaccine adjuvant and treatment for bacterial and fungal infections.

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    Compound Overview

    Class of Compound:


    Mechanism of Action:

    Thymosin alpha-1 (Ta1) is derived from the thymus gland and enhances immune responses mediated by T-cells through various mechanisms. These include promoting T-cell differentiation and maturation, activating natural killer cells, stimulating dendritic cells, and triggering the release of proinflammatory cytokines.

    Notable Studies:

    Also Known As:

    Thymalfasin, Zadaxin, EMZ702

    Research Applications:

    • Immunodeficiency disorders
    • Vaccine adjuvant
    • Bacterial and fungal infections
    • Neuroprotection


    • Injection site reactions
    • Headache
    • Nausea and vomiting
    • Fatigue

    Chemical Structure

    Thymosin Alpha-1 structure

    What is Thymosin Alpha-1?

    Thymosin alpha-1 (Ta1) is a peptide that derives from the thymus hormone called thymosin fraction 5. Known for its potent immunomodulatory properties, Ta1 has garnered serious interest for its potential to address various immune-related illnesses.

    Ta1 consists of 28 amino acids and is found in the thymus gland. The thymus is a vital organ involved in the development of T-cells, immune cell maturation, and adaptive immunity. Ta1 acts as an immunoregulatory molecule, modulating immune responses and promoting immune system functionality [1].

    Thymosin alpha-1 has a long history of development and regulatory evaluation. It first attracted interest as a possible immunodeficiency therapy and as a vaccine adjuvant. Clinical research on thymosin alpha-1 increased in scope in the 1990s to include the treatment of certain cancers and viral infections [1].

    Ta1 has received regulatory approval in some countries for certain indications such as viral infections, cancer, and chronic hepatitis B and C. The regulatory environment is still changing, and ongoing studies aim to clarify the safety and effectiveness of Ta1 in diverse medical applications [2].

    Thymosin Alpha-1

    What Does Thymosin Alpha-1 Do?

    Thymosin alpha-1 exerts its immunomodulatory effects through various mechanisms. In this section, we break down what Ta1 does, its mechanism of action, and its potential importance in clinical practice.

    Ta1 modulates immune responses by influencing the functions of different immune cells while regulating cytokine and chemokine production. It helps restore immune balance and enhances the body's defense mechanisms [2].

    This is largely achieved through its promotion of the maturation and function of T-cells, which are key players in adaptive immunity. Thymosin alpha-1 improves T-cell differentiation and antigen recognition and activation, thereby enhancing the immune response against pathogens including viruses and cancer cells [2].

    In this capacity, Ta1 demonstrates direct antiviral effects against various viruses, including hepatitis B and C, HIV, and CMV. It can inhibit viral replication and contribute to the clearance of virus-infected cells [3, 4].

    Further, Ta1 has been shown to enhance the activity of natural killer (NK) cells, which are important in the early defense against viral infections and cancer. It boosts NK cell-mediated cytotoxicity, aiding in the elimination of infected or malignant cells. A potential anti-tumor agent, Ta1 promotes the production and activation of cytotoxic T-cells, NK cells, and dendritic cells involved in tumor surveillance and elimination [3, 4].

    Thymosin Alpha-1 Benefits | Clinical Trials

    Studies on Ta1 indicate its promise in various clinical areas, summarized as follows.

    Treatment of hepatitis C: Ta1 has shown potential as an immunomodulatory peptide in improving treatment outcomes for hepatitis C virus (HCV) when used in combination with standard care. Its immunomodulatory properties, including T-cell function enhancement and cytokine production regulation, may enhance treatment response and reduce liver inflammation [5].

    However, clinical trials combining Ta1 with interferon-based therapies, the standard treatment for HCV, have not provided definitive evidence supporting its efficacy. Despite these findings, the potential of Ta1 as an adjunctive therapy for HCV remains a topic of investigation [6].

    Treatment of hepatitis B: Zhang et al. (2009) conducted a comprehensive literature review to evaluate the efficacy of combining lamivudine and thymosin alpha-1 in treating hepatitis B virus (HBV) infection. The study included eight trials involving 583 patients.

    The results demonstrated that the combination of lamivudine and Ta1 yielded significant improvements compared to lamivudine treatment alone. Specifically, there were notable advancements in the normalization rate of alanine aminotransferase (ALT), the virological response rate, and the hepatitis B e antigen (HBeAg) seroconversion rate.

    ALT normalization signifies enhanced liver function, while virological response and HBeAg seroconversion indicate reduced viral replication and transition to an inactive HBV carrier state. The favorable outcomes in these aspects suggest that adding Ta1 to lamivudine treatment may augment therapeutic effects in patients with HBV infection [7].

    COVID-19 treatment: In a pilot trial conducted by Shehadeh et al. (2022), the efficacy and safety of thymalfasin, a synthetic form of thymosin alpha-1, were evaluated in comparison to the standard of care for hospitalized patients with COVID-19 who experienced hypoxemia and lymphocytopenia.

    The trial was a prospective, open-label, randomized study. The results indicated that treatment with Ta1 led to a faster increase in CD4+ T-cell count among patients who required low-flow oxygen support at baseline, compared to the standard of care. This finding suggests that Ta1 may play a role in managing hospitalized COVID-19 patients with hypoxemia and lymphocytopenia [9].

    Immunodeficiency disorders: Thymosin alpha-1 has also shown the potential to modulate the immune response against viral infections such as HIV-1 and HTLV-1. In an in vitro study conducted by Matteucci et al. (2015), Ta1 was found to inhibit HIV-1 infection of macrophages (MDMs) and PBMCs, as well as HTLV-1 infection of PBMCs, while positively impacting gene expression in immune cells associated with HIV infection [10].

    Vaccine adjuvant: The utilization of thymosin alpha-1 as an adjuvant to the influenza vaccine has demonstrated encouraging outcomes, particularly in elderly and immunocompromised populations. Studies indicate that thymosin alpha-1 can enhance the immune response generated by the influenza vaccine, improving immunogenicity [11].

    Bacterial and fungal infections:Thymosin alpha-1 has been investigated for its potential therapeutic benefits in various infectious conditions, including Pseudomonas infections and infections following bone marrow transplantation. In the case of Pseudomonas infections, Ta1 has shown promising immunomodulatory effects that can enhance the immune response against the bacteria [12].

    Thymosin alpha-1 exhibits immunomodulatory effects that contribute to the generation of an antifungal immune response, as well. It is shown to enhance the development and function of Th1 and regulatory T (Treg) cells, which help to balance inflammation and promote an effective antifungal response [13].

    Other possible applications: Thymosin alpha-1 is also under investigation for its utility in treating chronic fatigue syndrome and psoriatic arthritis. It is of further interest for its purported anti-aging and neuroprotective properties.

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    Thymosin Alpha-1 Side Effects

    Thymosin alpha-1 exhibits good safety and tolerability with proper administration. While some side effects have been observed, they are generally transient and mild. The most frequent are injections site reactions, such as redness, swelling, and pain.

    The following potential side effects were identified by Miao et al. (2010) in a thorough randomized trial that examined the frequency of serious adverse events (SAEs) and treatment-related adverse events (AEs) in thymosin alpha-1 peptide therapy [14]:

    • Nausea
    • Vomiting
    • Diarrhea
    • Constipation
    • Headache
    • Chills
    • Asthenia
    • Chest pain

    This study generally affirmed the tolerability of Ta1 in a variety of demographics, despite the fact that the extent and rate of these adverse events were not disclosed.

    In summation, although overall safe and well-tolerated, thymosin alpha-1 has a few modest side effects, chiefly local responses at the site of injection.

    The occurrence of treatment-related adverse events and serious adverse events seems to be negligible, pointing to Ta1’s good safety profile.

    Is Thymosin Alpha-1 Safe?

    Thymosin alpha-1 is deemed to be safe when used under professional supervision. It has been studied extensively, and clinical trials have evaluated its safety profile in various patient populations.

    The available evidence suggests that Ta1 has a favorable safety profile with minimal side effects [14]. Commonly reported side effects are modest and transient reactions at the injection site, such as swelling, redness, or pain. These local reactions are generally well-tolerated and tend to subside on their own without the need for intervention.

    While recent studies support the safety and tolerability of thymosin alpha-1, researchers are urged to thoroughly review the potential risks of its use for research purposes.

    Thymosin alpha-1 should strictly be administered by qualified researchers, and it is not suited for self-administration in non-scientific contexts.

    Thymosin Alpha-1 Dosing and Cycling

    A suitable experimental dosage of thymosin alpha-1 depends on the research context. For example, the applicable dosage in clinical studies typically ranges from 0.8mg to 6.4mg twice weekly, while some studies have featured up to 16mg a day for seven days. Thymosin alpha-1 is administered via subcutaneous injection.

    While thymosin alpha-1 has a positive safety profile, individual responses to the peptide may vary. Researchers should adhere to dosage guidelines and adjust as needed according to the subject's tolerance.

    Sample Thymosin Alpha-1 Dosing Protocol

    Here is a sample dosing protocol of thymosin alpha-1 for enhanced immune function and cellular repair.

    • Thymosin Alpha-1 Dosage: 500mcg once a day via subcutaneous injection.
    • Duration: 20 days
    • Notes: One 10mg vial from our top-recommended retailer contains a complete 20-day supply.

    Injections must be administered properly, utilizing aseptic handling procedures and keeping an eye out for negative side effects. If there are any serious negative effects, cease administration and seek medical assistance as needed.

    To safeguard peptide stability, store thymosin alpha-1 vials according to the instructions provided by the manufacturer. For security, effectiveness, and quality in experimentation, make sure to buy all peptides from a reputable supplier.

    Where to Buy Thymosin Alpha-1 Online?

    To purchase top-quality thymosin alpha-1 for your research, look no further than Peptide Sciences, the go-to vendor among peptide specialists.

    Here a just some of the outstanding benefits of Peptide Sciences:

    • USA-made peptides: A thorough quality control strategy is in place at Peptide Sciences, and it includes screening and overseeing its production partners. This vendor obtains all peptides from domestic producers who follow Good Manufacturing Practices (GMP).
    • Verified purity: Thymosin alpha-1 at 99%+ purity is available from Peptide Sciences. The vendor tests the purity of their products using high-performance liquid chromatography and mass spectrometry techniques.
    • Fast shipping: Peptide Sciences provides safe online shopping as well as prompt, dependable shipment. They offer reasonable delivery costs as well as free domestic shipping for orders over $200. All orders are promptly dispatched to avoid delays.
    • Expert information: Peptide Sciences' website has thorough research overviews on all listed peptides, including thymosin alpha-1. They also provide useful advice on how to administer, handle, and reconstitute peptides.

    For all your thymosin alpha-1 research needs, picking a trustworthy supplier like Peptide Sciences is essential to guaranteeing safe research.

    Peptide Sciences is the best option for purchasing thymosin alpha-1 online due to their dedication to quality control, product purity, and trustworthy shipping.

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    How to Reconstitute Thymosin Alpha-1

    Thymosin alpha-1 is normally sold as a lyophilized powder for research use and requires reconstitution before injection with a sterile solvent. Although utilizing sterile water is an option, bacteriostatic water is recommended to increase the peptide solution's shelf-life.

    Bacteriostatic water includes 0.9% benzyl alcohol, an organic preservative that inhibits the growth of bacteria. If refrigerated, it can be kept for four weeks upon opening.

    By contrast, sterile water has no preservative content and cannot prevent the growth of microorganisms. Any peptide that has been reconstituted with it becomes unusable after 24 hours, regardless of refrigeration.

    If properly stored in the refrigerator at 2-8 degrees C (36-46 degrees F), bacteriostatic water extends the solution's shelf life by approximately 4 weeks. Reconstituted peptides should not be frozen because doing so renders them inert.

    Materials for Reconstitution

    To correctly reconstitute thymosin alpha-1, the following items are required:

    • Vial of quality bacteriostatic water
    • Vial of lyophilized Thymosin Alpha-1 powder
    • Sterile syringe of minimum 3cc
    • Sterile needle (1" 20-gauge)
    • Alcohol wipes
    • Disposable sharps container

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    Reconstitution Process

    Follow these steps to correctly reconstitute thymosin alpha-1:

    Step 1: The peptide and bacteriostatic water vials should be kept at room temperature before reconstitution. Store them in a cool environment, out of direct sunlight.

    Step 2: Clean the work area and your hands thoroughly to maintain a sterile environment. Wipe both vials and their rubber stoppers with an alcohol swab to disinfect.

    Step 3: Draw up the appropriate amount of bacteriostatic water into a syringe. The exact amount will depend on the concentration of thymosin alpha-1 you have and the desired dosage.

    Step 4: Inject the bacteriostatic water into the thymosin alpha-1 vial by slowly directing the syringe along the vial's wall. Avoid direct contact between the liquid and the powder to minimize foaming. Dispose of the syringe and needle in a sharps container.

    Step 5: Gently swirl the vial until the powder is completely dissolved. Do not shake vigorously, as it can denature the peptide. Sonication may be used if available.

    Step 6: If the solution is clear, it is ready for use. If it appears cloudy, the solution is not safe for injection and must be discarded.

    Step 7: Precise storage and dosage recommendations are subject to variation. Always reference product labeling for manufacturer instructions.

    Thymosin Alpha-1 Injections | A-Z Guide

    After loading the injection with the reconstituted peptide, following the proper steps for administering the injection is crucial. Here is a step-by-step guide:

    1. Prepare a clean, well-lit area and wash your hands thoroughly.
    2. Rotate injection sites between the abdomen, thighs, or upper arms.
    3. Cleanse the injection site with an alcohol swab and let it air dry.
    4. Remove air bubbles by tapping the syringe and pushing the plunger slightly.
    5. Position the syringe like a pen, insert the needle at a 90-degree angle, and inject slowly.
    6. Withdraw the needle, applying gentle pressure to the injection site with a sterile cotton ball.
    7. Dispose of the syringe and needle in a puncture-proof container according to local regulations.
    8. Observe the injection site for any adverse reactions or complications.

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    Is Thymosin Alpha-1 Legal?

    Thymosin alpha-1 is not approved by the United States Food and Drug Administration for any specific human use. It is considered an investigational drug and is primarily used in clinical research and trials.

    Qualified researchers may safely and legally obtain thymosin alpha-1 for educational purposes from a credible source like Peptide Sciences.

    All buyers should be advised that thymosin alpha-1 is neither sold over-the-counter nor as an authorized dietary supplement. Marketing it as such is both illegal and potentially dangerous to the consumer.

    Individuals who are not lab professionals or qualified researchers are urged against the purchase or possession of thymosin alpha-1 within the United States. Residents of other countries must consult pertinent regulations.

    Thymosin Alpha-1


    Thymosin Alpha-1. Just. Works.

    Thymosin Alpha-1 has shown potential in various applications. It has been used in the treatment of chronic hepatitis B and C, boosting the antiviral immune response. Additionally, it has been used as an adjunctive therapy for certain cancers and immunodeficiency disorders, and as a treatment for bacterial and fungal infections.

    It has likewise shown promise in conditions such as chronic fatigue syndrome, psoriatic arthritis, and even age-related issues. Research has also explored its potential neuroprotective properties. This already impressive list is sure to expand with avid studies underway.

    Researchers can safely add thymosin alpha-1 to their investigations by purchasing top-notch products from our approved supplier.

    Peptide Sciences is known for their excellent products, reliable shipping, and secure business practices.


    1. Maio M, Mackiewicz A, Testori A, Trefzer U, Ferraresi V, Jassem J, Garbe C, Lesimple T, Guillot B, Gascon P, Gilde K, Camerini R, Cognetti F; Thymosin Melanoma Investigation Group. Large randomized study of thymosin alpha 1, interferon alfa, or both in combination with dacarbazine in patients with metastatic melanoma. J Clin Oncol. 2010 Apr 1;28(10):1780-7. doi: 10.1200/JCO.2009.25.5208. Epub 2010 Mar 1. PMID: 20194853..
    2. Tuthill C, Rios I, McBeath R. Thymosin alpha 1: past clinical experience and future promise. Ann N Y Acad Sci. 2010 Apr;1194:130-5.0
    3. King R, Tuthill C.. Immune Modulation with Thymosin Alpha 1 Treatment. Vitam Horm 2016;102:151-78.
    4. Camerini R, Garaci EHistorical review of thymosin α 1 in infectious diseases. Expert Opin Biol Ther. 2015;15 Suppl 1:S117-27
    5. Sherman KE. Thymosin alpha 1 for treatment of hepatitis C virus: promise and proof.
      Ann N Y Acad Sci. 2010 Apr;1194:136-40.
    6. Ciancio A, Andreone P, Kaiser S, Mangia A, Milella M, Solà R, Pol S, Tsianos E, De Rosa A, Camerini R, McBeath R, Rizzetto MThymosin alpha-1 with peginterferon alfa-2a/ribavirin for chronic hepatitis C not responsive to IFN/ribavirin: an adjuvant role? J Viral Hepat. 2012 Jan;19 Suppl 1:52-9.
    7. Zhang YY, Chen EQ, Yang J, Duan YR, Tang H. Treatment with lamivudine versus lamivudine and thymosin alpha-1 for e antigen-positive chronic hepatitis B patients: a meta-analysis. Virol J. 2009 May 25;6:63.
    8. Wei Y, Zhang Y, Li P, Yan C, Wang L.Thymosin α-1 in cancer therapy: Immunoregulation and potential applications. Int Immunopharmacol. 2023 Apr;117:109744.
    9. Shehadeh F, Benitez G, Mylona EK, Tran QL, Tsikala-Vafea M, Atalla E, Kaczynski M, Mylonakis E. A Pilot Trial of Thymalfasin (Thymosin-α-1) to Treat Hospitalized Patients With Hypoxemia and Lymphocytopenia Due to Coronavirus Disease 2019 Infection. J Infect Dis. 2023 Jan 11;227(2):226-235
    10. Matteucci C, Minutolo A, Pollicita M, Balestrieri E, Grelli S, D'Ettorre G, Vullo V, Bucci I, Luchini A, Aquaro S, Sinibaldi-Vallebona P, Macchi B, Perno CF, Mastino A, Garaci E. Thymosin α 1 potentiates the release by CD8(+) cells of soluble factors able to inhibit HIV-1 and human T lymphotropic virus 1 infection in vitro.
      Expert Opin Biol Ther. 2015;15 Suppl 1:S83-100.
    11. Panatto D, Amicizia D, Lai PL, Camerini R, De Rosa A, Gasparini R. Utility of thymosin alpha-1 (Zadaxin) as a co-adjuvant in influenza vaccines: a review. J Prev Med Hyg. 2011;52:111-115.
    12. Asimina Dominari, Donald Hathaway III, Krunal Pandav, Wanessa Matos, et al. Thymosin alpha 1: A comprehensive review of the literature. World J Virol. 2020 Dec 15; 9(5): 67–78.
    13. Antachopoulos C, Katragkou A, Roilides E. Immunotherapy against invasive mold infections. Immunotherapy. 2012;4:107-120.
    14. Maio M, Mackiewicz A, Testori A, Trefzer U, Ferraresi V, Jassem J, Garbe C, Lesimple T, Guillot B, Gascon P, Gilde K, Camerini R, Cognetti F; Thymosin Melanoma Investigation Group. Large randomized study of thymosin alpha 1, interferon alfa, or both in combination with dacarbazine in patients with metastatic melanoma. J Clin Oncol. 2010 Apr 1;28(10):1780-7.