Thymosin Alpha-1
Thymosin Alpha-1 (Tα1) is a 28-amino-acid peptide hormone produced by the thymus with immunomodulatory, anti-inflammatory, and antioxidant properties that stimulate T-cell differentiation and enhance thymic output [1]. It has been studied across a range of conditions including severe infections, cancer, sepsis, chronic obstructive pulmonary disease, and acute pancreatitis, with its strongest clinical evidence coming from systematic reviews and meta-analyses in infectious and inflammatory disease contexts [3] [4]. Most mechanistic and dose-related data derive from animal and in vitro models; human pharmacokinetic data and regulatory approval status are not documented in the current research packet.
44/52 claims verified by independent fact-checker.
2 claims pending coverage
- Evidence tier below threshold(1 claim)
- Same issue as above — cf9750cc is a breast cancer/zerumbone paper. This citation is used at least three times in the draft (summary, mechanism section, FAQ) and fails each time. The source does not match the claim. FAILED.(1 claim)
Pepteligence regenerates entries quarterly and when new high-tier evidence appears.
Quick facts
Suggested labs for this peptide class — educational reference only; not medical advice.
TL;DR
- Half-life: — — dosed —.
- Administered via subcutaneous.
- Evidence base: observational data.
- Primary goals: immune, inflammation.
Observational studies
How it works
Tα1 is a 28-amino-acid peptide hormone endogenously produced by the thymus with immunomodulatory, anti-inflammatory, and antioxidant properties that stimulate T-cell differentiation and enhance thymic output [1]. Mechanistic data indicate that Tα1 acts through Toll-like receptors in myeloid and plasmacytoid dendritic cells, leading to activation of downstream signaling pathways and production of immune-related cytokines [8]. In vitro evidence further indicates that Tα1 modulates the immune synapse in dendritic cells by upregulating co-stimulatory markers CD40 and CD80 while reducing inhibitory markers TIM-3 and PD-L1, and suppressing TNF-α production, during cytomegalovirus infection [9]. Animal and in vitro studies suggest Tα1 activates the tolerogenic tryptophan catabolism pathway via indoleamine 2,3-dioxygenase (IDO), which may potentiate immune tolerance and help break cycles of chronic inflammation [10]. In vitro PBMC model data point to Tα1 acting as a master regulator of immune homeostasis with mitigating effects on cytokine storm and T-cell exhaustion in SARS-CoV-2 infection [15]. Animal studies indicate that when combined with IL-15 in aged mice with hepatocellular carcinoma, Tα1 reduces senescent hepatic CD8+ T cells via suppression of the PI3K/AKT signaling pathway [16]. Mechanistic data also suggest Tα1 reverses oncolytic adenovirus-induced M2 macrophage polarization toward an antitumor phenotype in cell cultures and mouse models [17]. Endogenous Tα1 is present in the rat central nervous system, particularly in the hippocampus, spinal cord, and glial cells [2], and serum Tα1 levels are significantly reduced in patients with chronic inflammatory autoimmune diseases including psoriatic arthritis, rheumatoid arthritis, and systemic lupus erythematosus compared to healthy controls [14].
What the research says
Research summary content coming soon. Check the references section for indexed studies.
Protocol lifecycle
Before — Pre-cycle readiness
Readiness checklist
Medical history
Baseline labs
- Complete blood count with differential
- Lymphocyte subset panel (CD4, CD8, NK cells) — relevant to Tα1's primary mechanism of T-cell differentiation [8]
- Liver function tests — hepatic immune cell activity is a focus of mechanistic data [16]
- Inflammatory markers (CRP, ESR) — serum Tα1 levels correlate inversely with inflammatory autoimmune disease states [14]
Sourcing and formulation
- Obtain from a verified compounding pharmacy or research-grade supplier with documented peptide purity and sterility testing
- Confirm subcutaneous administration preparation (sterile reconstitution); novel liquid crystal depot formulations are under investigation but not clinically validated in humans [22]
Regulatory and legal
- Regulatory approval status by jurisdiction (FDA, EMA, Health Canada) is not documented in the current research packet; verify local legal status before use
- Informed consent regarding research-only status and absence of validated human dosing protocols
- Baseline immune panel (lymphocyte subsets, CD4/CD8 ratio) recommended given Tα1's primary mechanism of T-cell modulation [8].
- Screen for concurrent use of immune checkpoint inhibitors (PD-1, CTLA-4 inhibitors); a case report documents serious multisystem immune-related adverse events with sintilimab combination [6].
- Assess baseline inflammatory autoimmune disease status; serum Tα1 is significantly reduced in patients with psoriatic arthritis, rheumatoid arthritis, and SLE compared to healthy controls, which may inform clinical context [14].
During — Active protocol
- Monitor for signs of immune dysregulation, including fever, rash, and respiratory symptoms, particularly when co-administered with checkpoint inhibitors [6].
- In pancreatitis settings, systematic review and meta-analysis evidence supports immune monitoring as a marker of treatment response [3].
- In COPD exacerbation settings, systematic review data indicate that Tα1 added to routine treatment may alleviate acute exacerbations; clinical response monitoring is appropriate [4].
After — Post-cycle
- Optimal cycle length and off-period duration are not established by human clinical trial data in the current research packet; cycling guidance cannot be evidence-based at this time.
- Repeat immune profiling (lymphocyte subsets) after a treatment course may help assess immunological response, consistent with the mechanistic literature on T-cell modulation [8].
Stacks it appears in
Related peptides
Other compounds indexed on Pepteligence that share research tags with Thymosin Alpha-1. Educational context only.
Safety
Common side effects
- ·Injection site reactions (implied by subcutaneous route; not systematically characterized in sources within the current research packet)
Rare side effects
- ·Fever, rash — reported in a case report of Tα1 combined with the PD-1 inhibitor sintilimab [6]
- Multisystem immune-related adverse events including interstitial pulmonary edema and multiple organ failure when combined with sintilimab (PD-1 inhibitor) — documented in a case report [6]
- Immune overstimulation risk when combined with immune checkpoint inhibitors; risk stratification data limited to case-level evidence [6]
Contraindications
- ·Concurrent use of PD-1 or CTLA-4 immune checkpoint inhibitors without specialist monitoring — a case report documents life-threatening multisystem immune-related adverse events with the sintilimab combination [6]
- ·No absolute contraindications are explicitly stated in the current research packet; however, immunocompromised patients and those with active autoimmune disease require careful clinical assessment before use given Tα1's potent immunomodulatory mechanism [8]
Community experiences
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Thymosin Alpha-1 — at a glance
| Property | Thymosin Alpha-1 | — |
|---|---|---|
| Half-life | — | — |
| Route | subcutaneous | — |
| Typical dose | See research context | — |
| Mechanism | Tα1 is a 28-amino-acid peptide hormone endogenously produced by the thymus with immunomodulatory, anti-inflammatory, and antioxidant properties that stimulate T-cell differentiation and enhance thymic output. Mechanistic data indicate that Tα1 acts through Toll-like receptors in myeloid and plasmacytoid dendritic cells, leading to activation of downstream signaling pathways and production of immune-related cytokines. In vitro evidence further indicates that Tα1 modulates the immune synapse in dendritic cells by upregulating co-stimulatory markers CD40 and CD80 while reducing inhibitory markers TIM-3 and PD-L1, and suppressing TNF-α production, during cytomegalovirus infection. Animal and in vitro studies suggest Tα1 activates the tolerogenic tryptophan catabolism pathway via indoleamine 2,3-dioxygenase (IDO), which may potentiate immune tolerance and help break cycles of chronic inflammation. In vitro PBMC model data point to Tα1 acting as a master regulator of immune homeostasis with mitigating effects on cytokine storm and T-cell exhaustion in SARS-CoV-2 infection. Animal studies indicate that when combined with IL-15 in aged mice with hepatocellular carcinoma, Tα1 reduces senescent hepatic CD8+ T cells via suppression of the PI3K/AKT signaling pathway. Mechanistic data also suggest Tα1 reverses oncolytic adenovirus-induced M2 macrophage polarization toward an antitumor phenotype in cell cultures and mouse models. Endogenous Tα1 is present in the rat central nervous system, particularly in the hippocampus, spinal cord, and glial cells, and serum Tα1 levels are significantly reduced in patients with chronic inflammatory autoimmune diseases including psoriatic arthritis, rheumatoid arthritis, and systemic lupus erythematosus compared to healthy controls. | — |
| Evidence strength | observational | anecdotal |
| Primary goal | immune | — |
Frequently asked questions
What is Thymosin Alpha-1?
How does Thymosin Alpha-1 work?
What is Thymosin Alpha-1 used for?
Is Thymosin Alpha-1 FDA-approved?
Is Thymosin Alpha-1 naturally occurring?
What are common dosages of Thymosin Alpha-1?
How is Thymosin Alpha-1 administered?
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Who should not take Thymosin Alpha-1?
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References
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Zerumbone mediated CD1d inhibition suppresses epithelial to mesenchymal transition in triple negative breast cancer.
Shyanti Ritis Kumar, Sharma Sudhanshu, Haque Mazharul et al.
Discover Oncology · 2026 · PMID 41511636
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Evidence that endogenous thymosin alpha-1 is present in the rat central nervous system.
Turrini P, Aloe L
Neurochemistry International · 1999 · PMID 10524714
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Thymosin alpha 1 alleviates inflammation and prevents infection in patients with severe acute pancreatitis through immune regulation: a systematic review and meta-analysis.
Tian Yong, Yao Jiaqi, Ma Yihan et al.
Frontiers in Immunology · 2025 · PMID 40599771
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Thymosin Alpha 1 Plus Routine Treatment for the Acute Exacerbation of Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis.
Cao Ailing, Feng Fanchao, Zhou Xianmei
Journal of the College of Physicians and Surgeons — Pakistan · 2024 · PMID 39648386
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Comprehensive Review of the Safety and Efficacy of Thymosin Alpha 1 in Human Clinical Trials.
Dinetz Elliot, Lee Edwin
Alternative Therapies in Health and Medicine · 2024 · PMID 38308608
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A Case Report of a Multisystemic Immune-Related Adverse Event Caused by Sintilimab in Combination With Thymosin Alpha-1.
Li Ting, Wu Bao-Liang, Yu Cai-Long et al.
Clinical Case Reports · 2026 · PMID 41669704
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The efficacy and safety of thymosin alpha-1 combined with lenvatinib plus sintilimab in unresectable hepatocellular carcinoma: a retrospective study.
Yao Siyang, Huang Qiangsong, Zou Yan et al.
Scientific Reports · 2025 · PMID 40263352
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Immune Modulation with Thymosin Alpha 1 Treatment.
King R, Tuthill C
Vitamins and Hormones · 2016 · PMID 27450734
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Immune modulation via dendritic cells by the effect of Thymosin-alpha-1 on immune synapse in HCMV infection.
Espinar-Buitrago M S, Vazquez-Alejo E, Magro-Lopez E et al.
International Immunopharmacology · 2023 · PMID 38149577
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Cellular proteostasis: a new twist in the action of thymosin α1.
Stincardini Claudia, Renga Giorgia, Villella Valeria et al.
Expert Opinion on Biological Therapy · 2018 · PMID 30063867
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Immunopotentiator thymosin alpha-1 attenuates inflammatory pain by modulating the Wnt3a/β-catenin pathway in spinal cord.
Huang Jiahua, Jiang Huaqing, Pan Meijun et al.
Neuroreport · 2020 · PMID 31764244
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Thymosin Alpha-1 Inhibits Complete Freund's Adjuvant-Induced Pain and Production of Microglia-Mediated Pro-inflammatory Cytokines in Spinal Cord.
Xu Yunlong, Jiang Yanjun, Wang Lin et al.
Neuroscience Bulletin · 2019 · PMID 30790216
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Psychological disturbance alters thymic and adrenal hormone secretion in a parallel but independent manner.
Coe C L, Hall N R
Psychoneuroendocrinology · 1996 · PMID 8774065
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Serum thymosin α 1 levels in patients with chronic inflammatory autoimmune diseases.
Pica F, Chimenti M S, Gaziano R et al.
Clinical and Experimental Immunology · 2016 · PMID 27350088
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Novel evidence of Thymosin α1 immunomodulatory properties in SARS-CoV-2 infection: Effect on innate inflammatory response in a peripheral blood mononuclear cell-based in vitro model.
Ricci Daniela, Etna Marilena Paola, Severa Martina et al.
International Immunopharmacology · 2023 · PMID 36933449
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IL-15 Plus Thymosin α1 Reduces Senescent Hepatic CD8+ T Cells in Hepatocellular Carcinoma via PI3K/AKT Suppression.
Wu Fengtian, Guo Zixuan, Guan Jun et al.
Journal of Gastroenterology and Hepatology · 2026 · PMID 41883056
View on PubMed → - [17]
Thymosin α1 reverses oncolytic adenovirus-induced M2 polarization of macrophages to improve antitumor immunity and therapeutic efficacy.
Liu Kua, Kong Lingkai, Cui Huawei et al.
Cell Reports Medicine · 2024 · PMID 39357524
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Safety and Efficacy of Nucleic Acid Polymers in Monotherapy and Combined with Immunotherapy in Treatment-Naive Bangladeshi Patients with HBeAg+ Chronic Hepatitis B Infection.
Al-Mahtab Mamun, Bazinet Michel, Vaillant Andrew
PLoS One · 2016 · PMID 27257978
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Anti-tumor effect of combined treatment with thymosin alpha 1 and interleukin-2 after 5-fluorouracil in liver metastases from colorectal cancer in rats.
Rasi G, Silecchia G, Sinibaldi-Vallebona P et al.
International Journal of Cancer · 1994 · PMID 8194879
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High doses of thymosin alpha 1 enhance the anti-tumor efficacy of combination chemo-immunotherapy for murine B16 melanoma.
Pica F, Fraschetti M, Matteucci C et al.
Anticancer Research · 1998 · PMID 9858941
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Combined effect of fluconazole and thymosin alpha 1 on systemic candidiasis in mice immunosuppressed by morphine treatments.
di Francesco P, Gaziano R, Casalinuovo I A et al.
Clinical and Experimental Immunology · 1994 · PMID 8082290
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Exploiting the potential of in situ forming liquid crystals: development and in vitro performance of long-acting depots for peptide drug thymosin alpha 1 subcutaneous administration.
Vitek Mercedes, Zvonar Pobirk Alenka, Roškar Robert et al.
Drug Delivery · 2025 · PMID 40066714
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Effect of thymosin α1 on Immune response and organ function in acute aortic dissection surgery: PANDA II trial protocol.
Liu Hong, Qian Si-Chong, Zhang Ying-Yuan et al.
Future Cardiology · 2025 · PMID 40367062
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Enhanced Immunomodulatory Effects of Thymosin-Alpha-1 in Combination with Polyanionic Carbosilane Dendrimers against HCMV Infection.
Espinar-Buitrago María de la Sierra, Magro-López Esmeralda, Vázquez-Alejo Elena et al.
International Journal of Molecular Sciences · 2024 · PMID 38396631
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Immune-Enhancing Treatment among Acute Necrotizing Pancreatitis Patients with Metabolic Abnormalities: A Post Hoc Analysis of a Randomized Clinical Trial.
Huang Xiaofei, Mao Wenjian, Hu Xingxing et al.
Gut and Liver · 2024 · PMID 38356344
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Impact of the immunomodulating peptide thymosin alpha 1 on multiple myeloma and immune recovery after hematopoietic stem cell transplantation.
Binsfeld Marilène, Hannon Muriel, Otjacques Eléonore et al.
Cancer Immunology, Immunotherapy · 2015 · PMID 25971542
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Thymosin Alpha1-Fc Modulates the Immune System and Down-regulates the Progression of Melanoma and Breast Cancer with a Prolonged Half-life.
Wang Fanwen, Yu Tingting, Zheng Heng et al.
Scientific Reports · 2018 · PMID 30120362
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Thymosin α1 represents a potential potent single-molecule-based therapy for cystic fibrosis.
Romani Luigina, Oikonomou Vasilis, Moretti Silvia et al.
Nature Medicine · 2017 · PMID 28394330
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[Thymosin alpha-1 and hybrid proteins consisting of tumor necrosis factor-alpha and thymosin alpha-1 enhance the efficacy of vaccination against the causative agent of plague].
Shmelev V A, Grigor'ev B V, Mozharova T I et al.
Zhurnal Mikrobiologii, Epidemiologii i Immunobiologii · 1994 · PMID 7992547
View on PubMed →