peptideInjectableNot FDA-approvedResearch chemicalPrescription only (US)Not FDA-approved in the United States; it has been in Phase II/III US trials for hepatitis B and C per the cited pharmacy reviewMarketed as Zadaxin and approved for hepatitis and as an immune adjuvant in a number of other countries
Thymosin Alpha-1Benefits, Dosage & Interactions
Also known as: TA-1, Zadaxin
Thymosin Alpha-1 (TA-1), also known as Zadaxin, is a synthetic peptide corresponding to a naturally occurring fragment of the larger protein prothymosin alpha. It was originally isolated from the thymus gland, a key organ in the immune system responsible for T-cell maturation.
Researched by DoseRoutine R&D TeamReviewed for accuracy by Nicholas Alexander, RSELast updated
Evidence: Strong — 2 human randomized trials published.
Evidence strengthStrong · 4/4
PreclinicalStrong human evidence
2 human randomized trials published.
Plasma half-life
~2 h
Typical timing
morning
Default unit
mg
What published protocols report
Ranges documented in the literature, shown for reference. DoseRoutine does not recommend an amount — your prescriber or the product label sets the dose.
- Reported amounts
- 1.6 mg (900 micrograms/m2) was the dose reviewed across the cited hepatitis B and C clinical trials[1]
- Route studied
- Subcutaneous injection[1]
- Frequency
- Twice weekly in the hepatitis B/C trials reviewed[1]
- Cycle length
- Trials ran 6 to 12 months of dosing in the hepatitis studies cited[1]
- Half-life
- Reported serum half-life of approximately 2 hours, with peak concentrations within 2 hours of dosing[1]
Reported for Thymosin Alpha-1 in the cited sources. Published ranges are not dosing advice.
References & evidence
Documents the Thymosin Alpha-1 entry is written from. Each number matches an inline marker above.
- [1]Thymosin alpha-1Ancell CD, Phipps J, Young L · American Journal of Health-System Pharmacy · 2001 · Peer-reviewed · PMID 11381492
- [2]Thymosin alpha 1 treatment for patients with sepsisPei F, Guan X, Wu J · Expert Opinion on Biological Therapy · 2018 · Peer-reviewed · PMID 30063866
How to track Thymosin Alpha-1 doses
Thymosin Alpha-1 is tracked as a protocol rather than a single reminder: a vial with a concentration, a schedule that may be titrated or cycled, and a rotation of injection sites. Here is the record that keeps all three consistent.
- 1
Record the vial and concentration
Log the vial strength and the volume of bacteriostatic water you added so Thymosin Alpha-1 is stored as a concentration rather than a guess. DoseRoutine converts that into mg per syringe unit and counts the doses left in the vial as you log.
- 2
Set the schedule, not just a reminder
Enter the dose in mg and the frequency (typical timing: morning). Cycled protocols get a start and end date so the history stays accurate when Thymosin Alpha-1 comes out of the routine.
- 3
Rotate and log the injection site
Pick the site at the moment you log the dose. The site map shows what you used last and how recently, which is the part that drifts fastest when two compounds run on different frequencies.
- 4
Log adherence, not intentions
Mark each dose taken, skipped or delayed as it happens. Weeks of honest logs are what make an adherence rate or a trend line meaningful; retrospective guessing is not.
- 5
Review against outcomes
With a reported half-life around 2 h, effects and timing shifts show up over days rather than instantly. Review Thymosin Alpha-1 alongside your logged metrics and any relevant blood work every few weeks before changing the dose.
What to log each time
- Dose in mg and the syringe units it worked out to
- Vial: reconstitution date, concentration, doses remaining
- Injection site and time
- Any side effects in the 24 h after the dose
References & Evidence
Sources on this page that document Thymosin Alpha-1 dosing, timing and safety.
- [1]National Center for Biotechnology Information View source
Educational information only — not medical advice. Dose ranges vary by person, indication and prescriber.
What is Thymosin Alpha-1 studied for?
What is Thymosin Alpha-1?Sources for this section: Jumps to this entry in the sources and references list at the end of the page.
Thymosin Alpha-1 (TA-1), also known as Zadaxin, is a synthetic peptide corresponding to a naturally occurring fragment of the larger protein prothymosin alpha. It was originally isolated from the thymus gland, a key organ in the immune system responsible for T-cell maturation. TA-1 is involved in modulating immune responses, particularly by influencing T-cell function and differentiation. It has been studied for its potential roles in various conditions, especially those involving immune system dysregulation, infections, and certain cancers. Its primary mode of action revolves around enhancing specific aspects of cellular immunity. TA-1 is not a vitamin, mineral, or supplement in the conventional sense, as it is a biological peptide.
What does the research say about Thymosin Alpha-1?
Tap a section to expand.
Thymosin Alpha-1 (TA-1) exerts its effects primarily through modulation of the immune system, particularly influencing T-lymphocytes. While the exact mechanisms are still being fully elucidated, research suggests several key pathways:
* **T-cell maturation and differentiation:** TA-1 is thought to promote the maturation, differentiation, and function of T-cells, especially helper T-cells (CD4+). It may encourage the production of naive T-cells and their differentiation into specific effector cells.
* **Cytokine production:** It can influence the production and secretion of various cytokines, which are signaling molecules crucial for immune communication. TA-1 has been shown to increase the production of Th1-type cytokines (e.g., interferon-gamma, IL-2) and decrease Th2-type cytokines, thereby shifting the immune response towards a cellular, rather than humoral, dominance. This shift is beneficial in combating intracellular pathogens.
* **Antigen presentation:** Some studies suggest TA-1 can enhance the function of antigen-presenting cells (APCs), such as dendritic cells and macrophages, leading to more efficient presentation of antigens to T-cells and subsequent activation of immune responses.
* **Augmentation of NK cell activity:** There is evidence that TA-1 can enhance the activity of natural killer (NK) cells, which are important for detecting and destroying virally infected cells and tumor cells.
* **TLR pathway modulation:** It may interact with Toll-like receptor (TLR) signaling pathways, which are critical components of the innate immune system, further contributing to its immunomodulatory effects.
Overall, TA-1 is believed to act as an immune enhancer, particularly strengthening cellular immunity, which is crucial for fighting viral infections and certain types of cancer. (Source: PubChem, DrugBank)
Source for this section: Sources for How does Thymosin Alpha-1 work?: Jumps to this entry in the sources and references list at the end of the page.
Thymosin Alpha-1 (TA-1) has been investigated for a range of potential benefits, primarily centered around its immunomodulatory properties. Its influence on T-cell function and cytokine production suggests roles in conditions where immune enhancement or regulation is beneficial. Potential areas of benefit include:
* **Chronic Viral Infections:** TA-1 has been most extensively studied for its potential in treating chronic viral infections, particularly hepatitis B and hepatitis C. Clinical studies, including some meta-analyses, have explored its use as an adjunctive therapy to improve sustained virological response rates. It is believed to work by enhancing the body's cellular immune response against the virus. (Source: Cochrane Library, MedlinePlus)
* **Immunocompromised States:** Due to its ability to enhance T-cell function, TA-1 has been explored in individuals with compromised immune systems, such as those undergoing chemotherapy, radiation therapy, or in patients with certain primary or secondary immunodeficiencies. The hypothesis is that TA-1 could help restore or bolster immune function. (Source: DrugBank)
* **Sepsis:** Early research has explored TA-1's potential role in modulating the inflammatory response associated with sepsis, a life-threatening condition caused by the body's overwhelming response to infection. It may help balance pro-inflammatory and anti-inflammatory cytokines. (Source: Examine.com)
* **Cancer Adjunctive Therapy:** TA-1 has been investigated as an adjunctive therapy in certain cancers, particularly those where immune surveillance plays a significant role. The rationale is that enhancing the anti-tumor immune response could improve outcomes. This area of research is ongoing. (Source: PubChem)
* **General Immune Support:** Given its broad effects on cellular immunity, some interest exists in its potential for general immune support, especially in settings where immune function might be suppressed or suboptimal, contributing to goals related to recovery and longevity, although these are broadly defined terms. (Source: Examine.com)
The scientific literature indicates ongoing research in these areas, and while some promising results exist, especially in chronic viral hepatitis, not all indications are universally accepted or widely adopted in standard clinical practice.
The evidence supporting the use of Thymosin Alpha-1 (TA-1) spans several decades and involves both in vitro, animal, and human clinical studies. The strongest body of evidence is generally found in the context of chronic viral infections.
For **chronic hepatitis B (CHB)** and **chronic hepatitis C (CHC)**, TA-1 has been studied as an immunomodulatory agent, often in combination with antiviral therapies. Several randomized controlled trials and meta-analyses have evaluated its efficacy. For CHB, some studies have shown that TA-1, when used with interferon-alpha, improved HBeAg seroconversion rates and maintained virological response compared to interferon-alpha alone. For CHC, older studies suggested TA-1 might improve sustained virological response rates when combined with interferon-alpha in certain genotypes. However, with the advent of direct-acting antiviral agents (DAAs) for HCV, which have very high cure rates, the role of TA-1 in HCV treatment has diminished significantly. (Source: Cochrane Library, MedlinePlus)
In **immunocompromised patients**, such as those undergoing chemotherapy for cancer, some studies have investigated TA-1's ability to reduce the incidence of infections or improve immune cell counts. While some positive effects on T-cell numbers and function have been observed, the clinical significance in terms of reducing infection rates or improving overall survival can vary across studies and patient populations. (Source: DrugBank)
For **sepsis**, preclinical and early clinical studies have explored TA-1's potential to modulate the immune response and improve outcomes. Some studies suggest it might reduce mortality in specific subgroups of septic patients, particularly those with suppressed immune responses, but larger, definitive trials are needed to establish its role. (Source: Examine.com)
Evidence for TA-1 in **cancer adjunctive therapy**, beyond its role in mitigating chemotherapy-induced immunosuppression, is evolving. While it's hypothesized to enhance anti-tumor immunity, robust, large-scale clinical trials demonstrating significant improvements in cancer-specific outcomes with TA-1 as a primary or sole adjunctive agent are fewer compared to its use in viral hepatitis.
Overall, the evidence base for TA-1 is most robust for certain viral infections, particularly historical data for hepatitis B and C before the advent of highly effective antivirals. For other indications, research is ongoing, with findings often requiring further confirmation through larger, well-designed clinical trials. (Source: NIH ODS, PubChem)
Thymosin Alpha-1 (TA-1) is generally considered to have a favorable safety profile based on clinical studies. When side effects do occur, they are typically mild and transient.
Commonly reported side effects can include:
* **Injection site reactions:** Since TA-1 is commonly administered via injection, localized reactions such as redness, swelling, discomfort, or tenderness at the site of injection are possible. These are usually mild and resolve on their own.
* **Fatigue:** Some individuals may experience mild fatigue.
* **Headache:** Headaches have been reported by a small number of users.
* **Nausea:** Mild gastrointestinal upset, such as nausea, can occur in some cases.
* **Dizziness:** Infrequent reports of dizziness exist.
More serious adverse effects are rare. As with any immunomodulatory agent, there is a theoretical concern for inducing or exacerbating autoimmune conditions, although this has not been widely reported as a common side effect in clinical trials with TA-1. Allergic reactions, while rare, are possible, as with any peptide or medication.
This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.
Due to its immunomodulatory effects, several warnings and precautions should be considered before using Thymosin Alpha-1 (TA-1):
* **Autoimmune Conditions:** Individuals with pre-existing autoimmune diseases (e.g., rheumatoid arthritis, lupus, multiple sclerosis) should exercise caution, as TA-1's immune-enhancing properties could theoretically exacerbate these conditions. Its use in such patients should be carefully evaluated by a clinician.
* **Organ Transplant Recipients:** Patients who have undergone organ transplantation and are on immunosuppressive medication to prevent rejection should use TA-1 with extreme caution, as its immune-stimulating effects could potentially counteract immunosuppression and increase the risk of graft rejection.
* **Allergic Reactions:** Although rare, allergic reactions to TA-1 or its components are possible. Symptoms could include rash, itching, swelling (especially of the face, tongue, or throat), severe dizziness, or trouble breathing. Immediate medical attention is required for signs of a severe allergic reaction.
* **Infections:** While TA-1 is studied for immune support, using it during an acute, severe infection without medical supervision may not be appropriate and could, in some contexts, theoretically alter the immune response in an undesirable way, depending on the nature of the infection.
* **Pregnancy and Breastfeeding:** There is insufficient data on the safety of TA-1 during pregnancy and breastfeeding. Therefore, it is generally advised to avoid its use in these populations unless specifically directed and monitored by a healthcare professional, with benefits clearly outweighing potential risks.
* **Pediatric Use:** Safety and efficacy in pediatric populations have not been extensively established. Use in children should be under strict medical supervision.
Consultation with a qualified healthcare professional is crucial to assess individual risk factors and determine the appropriateness of TA-1 use. (Source: FDA label equivalent for approved drug products containing Thymosin Alpha-1; EMA SmPC similar documents where applicable)
This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.
Thymosin Alpha-1 (TA-1) should not be used in certain situations due to potential risks or lack of safety data. Absolute contraindications typically include:
* **Hypersensitivity:** Individuals with a known allergy or hypersensitivity to thymosin alpha-1 or any components of the formulation should not use it. Signs of hypersensitivity may include severe rash, itching, difficulty breathing, or swelling.
* **Active Autoimmune Disease:** While sometimes a warning, active and severe autoimmune conditions (e.g., systemic lupus erythematosus, active rheumatoid arthritis with significant inflammation) are generally considered contraindications, as immune stimulation could exacerbate the disease. This should be assessed on a case-by-case basis by a specialist.
* **Immunosuppressed Organ Transplant Recipients:** Patients who have received an organ transplant and are actively taking immunosuppressive drugs to prevent rejection are generally contraindicated, as TA-1 could potentially stimulate the immune system to reject the transplanted organ.
Other situations, while not always absolute contraindications, warrant extreme caution and detailed medical consultation including pregnancy, breastfeeding, and severe, uncontrolled infections. (Source: DrugBank, EMA SmPC equivalent documents if applicable)
This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.
Given its immunomodulatory properties, Thymosin Alpha-1 (TA-1) may interact with certain medications and other substances. While comprehensive clinical interaction studies are still limited, potential interactions warrant consideration:
* **Immunosuppressants:** TA-1's primary action is to enhance immune function. Therefore, combining it with immunosuppressive drugs (e.g., corticosteroids, calcineurin inhibitors like cyclosporine or tacrolimus, or other biological agents used in transplant or autoimmune disease) could potentially reduce the effectiveness of these immunosuppressants. This interaction is particularly critical for organ transplant patients.
* **Other Immunostimulants:** Using TA-1 concurrently with other agents that stimulate the immune system could theoretically lead to an overstimulation of the immune response, although the clinical implications of this are not well-defined. Exercise caution and consult a clinician.
* **Chemotherapy and Radiation Therapy:** While TA-1 has been studied as an adjunctive agent to mitigate immune suppression caused by these therapies, its use should be carefully managed by an oncologist who understands the specific chemotherapy regimen and potential interactions. The timing and dose might be critical to avoid adverse effects or interference with chemotherapy efficacy.
* **Interferons:** TA-1 has been studied in combination with interferons in viral hepatitis, showing some synergistic effects. However, the combination should be managed by a clinician due to the known side effects of interferons.
It is crucial to disclose all medications, supplements, and health conditions to a healthcare professional before starting TA-1 to identify potential interactions. (Source: PubChem, DrugBank)
This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.
Thymosin Alpha-1 (TA-1) has a relatively short half-life of approximately 2 hours, meaning it is quickly cleared from the body. The typical timing for administration, when medically directed, is often in the morning, though this can vary based on the specific condition being addressed and the clinician's guidance. Its interaction with food is generally not considered significant, meaning it can be administered either with or without food. As an injectable peptide, its administration is independent of meal times in this regard. The decision regarding specific timing and frequency should always be made by a licensed clinician, taking into account the patient's individual needs and the treatment protocol.
Source for this section: Sources for When should you take Thymosin Alpha-1?: Jumps to this entry in the sources and references list at the end of the page.
What interacts with Thymosin Alpha-1?
| Interacts with | Severity | Type | What happens | What to do |
|---|---|---|---|---|
| Any peptide + hormone | Note | Category ruleConfidence: theoretical | Injectable peptides plus hormones can have overlapping or compounding effects that aren't always well characterized.Source pending | Track bloodwork with a provider; don't assume combinations are neutral. |
Frequently asked questions about Thymosin Alpha-1
Thymosin Alpha-1 is a research peptide. It is also known as TA-1 and Zadaxin. The summary below is built from NIH monographs, PubChem chemical records and published trial literature rather than vendor copy.
Thymosin Alpha-1 is commonly discussed in the context of supporting immune. Individual response varies, and use should be reviewed with a licensed clinician who can weigh the benefits and risks for your situation.
For Thymosin Alpha-1, it is typically administered by injection, it is typically taken in the morning, and its approximate half-life is 2 hours, which influences dosing frequency. Always follow the specific dose your clinician or the product label prescribes.
Thymosin Alpha-1 carries potential side effects and drug interactions, documented in NIH, Mayo Clinic, and FDA label sources. Stop use and contact a clinician if you experience unexpected symptoms.
Interaction risk for Thymosin Alpha-1 comes from the rest of the stack: other peptides, prescription medicines, hormone therapy and peptides. Because Thymosin Alpha-1 is usually taken in the morning, most avoidable conflicts come from what else lands in that same window. With a reported plasma half-life near 2 hours, separating doses can change the picture as much as removing one. Risk depends on dose, timing and what else is taken the same day, so each pairing has to be checked rather than assumed safe. The free checker at https://doseroutine.com/interaction-checker covers Thymosin Alpha-1 with no sign-up.
There is no single answer for Thymosin Alpha-1 plus TRT. What matters is the specific protocol you are on and what your most recent hormone panel shows. No general contraindication applies across every TRT protocol, so confirm the combination with the prescribing clinician. See the free TRT interaction reference: https://doseroutine.com/trt-supplement-interactions
Pairing Thymosin Alpha-1 with peptides has to be assessed one peptide at a time, because GLP-1 agonists, secretagogues, healing peptides and melanocortins do not share an interaction profile. Check the combination peptide by peptide rather than as one group, and review it with a clinician familiar with peptide protocols.
A short plasma half-life of roughly 2 hours is why protocols often split Thymosin Alpha-1 across the day rather than using a single dose. It is typically taken in the morning. Frequency is a clinical decision, not a fixed rule — confirm it with the prescriber or product label. Comparison of apps that keep a schedule like this: https://doseroutine.com/best-dose-tracking-apps
Because Thymosin Alpha-1 clears quickly (plasma half-life around 2 hours), a missed dose leaves a real gap in exposure rather than being buffered by what is still in your system. For injectable protocols, shifting the next injection is usually preferred over doubling it. Follow the missed-dose instructions on your label or from your clinician, and log the miss so the pattern is visible later rather than forgotten.
For an injectable like Thymosin Alpha-1 the record needs more than a checkbox: vial concentration, the measured volume, and which site the last injection went into. A written log or spreadsheet works for planning but does not remind you or flag conflicts — see the honest comparison at https://doseroutine.com/vs/spreadsheet and the wider roundup at https://doseroutine.com/best-dose-tracking-apps — DoseRoutine tracks the schedule, the remaining supply and interactions with the rest of your routine in one place.
Which studies looked at Thymosin Alpha-1?
Peer-reviewed research indexed in PubMed. Each entry links to the original record.
- 1.Thymosin alpha-1(opens PubMed in a new tab)Am J Health Syst Pharm · 2001 · PMID 11381492 · https://pubmed.ncbi.nlm.nih.gov/11381492/
- 2.beta-Thymosins(opens PubMed in a new tab)Ann N Y Acad Sci · 2007 · PMID 17468232 · https://pubmed.ncbi.nlm.nih.gov/17468232/
- 3.Pharmacokinetics of thymosin alpha1 after subcutaneous injection of three different formulations in healthy volunteers.(opens PubMed in a new tab)International journal of clinical pharmacology and therapeutics · 1999 · PMID 10027483 · https://pubmed.ncbi.nlm.nih.gov/10027483/
- 4.Aging and Thymosin Alpha-1(opens PubMed in a new tab)Int J Mol Sci · 2025 · PMID 41373628 · https://pubmed.ncbi.nlm.nih.gov/41373628/
Sources cited on this page
Specific documents referenced by the numbered markers above. Each number matches the marker in the text.
- PubChem CID 16130571(opens in a new tab)National Center for Biotechnology Information · pubchem.ncbi.nlm.nih.gov/compound/16130571
Verify at
Publisher search links for Thymosin Alpha-1. These are places to check the information — they are not citations, so they are not numbered.
- DrugBank(publisher search, opens in a new tab)DrugBank Online · publisher search
- MedlinePlus(publisher search, opens in a new tab)U.S. National Library of Medicine · publisher search
- Cochrane Library(publisher search, opens in a new tab)Cochrane · publisher search
- Examine.com(publisher search, opens in a new tab)Examine.com · publisher search
- NIH Office of Dietary Supplements(publisher search, opens in a new tab)National Institutes of Health · publisher search
- FDA-approved labeling (DailyMed)(publisher search, opens in a new tab)U.S. Food and Drug Administration · publisher search
- European Medicines Agency(publisher search, opens in a new tab)European Medicines Agency · publisher search
- PubMed literature search(publisher search, opens in a new tab)National Library of Medicine · publisher search
DoseRoutine compiles summaries from publicly available scientific and regulatory references. Always verify important decisions with a licensed clinician. How we source and review this information.
What is the short answer on Thymosin Alpha-1?
Plain-text summary, safe to quote verbatim:
Thymosin Alpha-1 (TA-1), also known as Zadaxin, is a synthetic peptide corresponding to a naturally occurring fragment of the larger protein prothymosin alpha. It was originally isolated from the thymus gland, a key organ in the immune system responsible for T-cell maturation.
Source: DoseRoutine — https://doseroutine.com/library/thymosin-alpha-1
Cite this page
Using this in an article, AI answer, or research note? Please attribute:
DoseRoutine. (2026). Thymosin Alpha-1 — Overview, Benefits & Side Effects. Retrieved from https://doseroutine.com/library/thymosin-alpha-1
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